The procedure of colonoscopy gained national attention in the  United States  in 1985 when  President   Ronald Reagan  underwent a life-saving colonoscopy. [ 76 ] [ 77 ] [ 78 ]


A survey on colonoscopy shows a poor understanding of its protective value and widespread misconceptions. The public has perceptual gaps around the purpose of colonoscopies, the subjective experience of the colonoscopy procedure, and the quantity of bowel preparation needed. [ 79 ]


Actors  Ryan Reynolds  and  Rob McElhenney  have used their social media platform to raise awareness about the importance of colonoscopy as a procedure for  colon cancer screening . They filmed their own colonoscopies as part of a campaign called "Lead From Behind", [ 80 ] [ 81 ]  demonstrating that the procedure can be both easy and lifesaving. [ 82 ] [ 83 ]


Courvoisier's principle  (known as  Courvoisier's sign  or  Courvoisier–Terrier's sign , or  Courvoisier syndrome ) states that a painless palpably enlarged  gallbladder   accompanied with mild  jaundice  is unlikely to be caused by  gallstones . Usually, the term is used to describe the physical examination finding of the  right-upper quadrant of the abdomen . This sign implicates possible  malignancy of the gallbladder  or  pancreas  and the swelling is unlikely due to  gallstones . [ 1 ] [ 2 ]


This observation is best explained as a matter of the gradual increase in gallbladder distention that occurs secondary to chronic processes versus the abrupt increase in gallbladder pressure observed in acute processes. Courvoisier's sign occurs due to the gradual (chronic) nature of the obstruction caused by cancer (e.g. pancreatic, often located in pancreatic head, cholangiocarcinoma, etc.), which gradually causes biliary back-pressure and gradually distends the gallbladder over time, without causing acute damage, thus without causing pain. Conversely, gallstones cause obstruction of the biliary tree in a more abrupt (acute) nature when the gallstone becomes suddenly lodged somewhere along the biliary tree, blocking the passage of bile. This process causes the gallbladder to distend as it contracts against an abruptly blocked/higher pressure biliary tree, resulting in acute inflammation of the gallbladder (acute cholecystitis) and right upper quadrant abdominal pain (i.e., not Courvoisier's sign). Fibrosis of the gallbladder is another chronic process that occurs due to repeated acute inflammation (i.e., chronic cholecystitis), resulting in a shrunken, fibrotic (therefore hard), and calcified gallbladder ("porcelain gallbladder"), which typically will not present with Courvoisier's sign and is diagnosed with imaging.


Ludwig Georg Courvoisier 's [ 3 ]  original observations, published in Germany in 1890, were not originally cited as a 'law', and no mention of malignancy or pain (tenderness) was made. These points are commonly misquoted or confused in the medical literature. [ 4 ]


Exceptions to Courvoisier's law imply that a stone is responsible for jaundice and a non-tender, palpable gall bladder. Typically gall bladder stones form slowly which allow time for the gall bladder to become tender. The exceptions to the law are stones that dislodge and acutely block the duct distally to the hepatic/cystic duct junction:


Cholangiocarcinoma ,  Klatskin tumors , ascariasis, or recurrent pyogenic cholangitis are not exceptions to the law because they all fall under it. For example, in the case of  recurrent pyogenic cholangitis  complicated by calcium bilirubinate stone dislodging to the common bile duct causing a distended gallbladder by back pressure. (Where formation of stones are not strictly in gallbladder, hence not fibrotic, but in the  intrahepatic bile ducts ). To reiterate, the law simply says that jaundice and non-tender, palpable gall bladders are caused by other things than chronic bile gallstone formation. [ citation needed ]


The law does not say that these symptoms automatically mean pancreatic cancer. It just happens that pancreatic cancer is the most common cause that falls under Courvoisier's law. [ 4 ]  Other cause includes malignancy of the  CBD  (i.e.  cholangiocarcinoma ), head of  pancreas  and  ampulla of Vater .


A palpable  tender  gallbladder (hence the law cannot be applied) may be seen in acute acalculous  cholecystitis , which commonly follows trauma or  ischemia  and causes acute inflammation of the gallbladder in the absence of gallstones. [ citation needed ]


A palpable gallbladder without mild jaundice (hence the law cannot be applied) can also be seen in  Mirizzi's syndrome .


The following case is an illustration of using the rationale underlying the Courvoisier Law clinically. In a patient with a history of lung cancer presenting with jaundice and a non-palpable gallbladder it is likely that it is caused by a double cancer affected the common hepatic ducts and not from metastasis to the lymph node causing obstructive jaundice. This is because in the latter case, location of the lymph node has got to be in the CBD (simply by anatomical location) and one would expect a palpable gallbladder. All these speculations assume that the patient did not have gallstone disease previously (where the gallbladder would be fibrotic and not palpable) and that the patient does not have a history of other liver diseases (such as recurrent pyogenic cholangitis).


Double-balloon enteroscopy , also known as  push-and-pull  enteroscopy , is an  endoscopic  technique for visualization of the  small bowel .  It was developed by  Hironori Yamamoto  in 2001. [ 1 ]   It is novel in the field of diagnostic  gastroenterology  as it is the first endoscopic technique that allows for the entire  gastrointestinal tract  to be visualized in real time. [ 2 ]


The technique involves the use of a  balloon  at the end of a special  enteroscope  camera and an overtube, which is a tube that fits over the endoscope, and which is also fitted with a balloon. [ 2 ]   The procedure is usually done under general  anesthesia , but may be done with the use of  conscious sedation . [ 3 ]   The enteroscope and overtube are inserted through the  mouth  and passed in conventional fashion (that is, as with  gastroscopy ) into the  small bowel . [ 1 ]


Following this, the endoscope is advanced a small distance in front of the overtube and the balloon at the end is inflated.  Using the assistance of friction at the interface of the enteroscope and intestinal wall, the small bowel is accordioned back to the overtube.  The overtube balloon is then deployed, and the enteroscope balloon is deflated.  The process is then continued until the entire small bowel is visualized. [ 4 ]


The double-balloon enteroscope can also be passed in retrograde fashion, through the  colon  and into the  ileum  to visualize the end of the small bowel. [ 1 ]


Double-balloon enteroscopy has found a niche application in the following settings:


Double-balloon enteroscopy offers a number of advantages to other small bowel image techniques, including  barium  imaging,  wireless capsule endoscopy  and push enteroscopy:


The key disadvantage of double-balloon enteroscopy is the time required to visualize the small bowel; this can exceed three hours, and may require that patients be admitted to hospital for the procedure. [ 11 ]   There have also been case reports of  acute pancreatitis  (at a rate of 0.3%–0.4%, when the oral route is used) [ 12 ] [ 13 ]  and intestinal necrosis [ 14 ]  associated with the technique.


A 2015 study in the  World Journal of Gastrointestinal Endoscopy  reported that: "Due to prolonged procedure and air  insufflation ,  abdominal pain  can be observed in up to 20% patients." [ 12 ]  Depending on whether the oral or rectal approach was used, a patient may experience a sore throat (following use of the oral route), upset stomach, vomiting, and painful  bloating , cramping, or abdominal discomfort in reaction to the gas in the intestines. [ 15 ] [ 16 ]


An  electrogastrogram  ( EGG ) is a computer generated graphic produced by  electrogastrography , which detects, analyzes and records the myoelectrical signal generated by the movement of the smooth muscle of the stomach, intestines and other smooth muscle containing organs.  An  electrogastroenterogram  or electroviscerogram (or  gastroenterogram ) is a similar display of the recording of myoelectrical activity of gastrointestinal or other organs which are able to  generate myoelectrical activity.


These names are made of different parts:  electro , because it is related to electrical activity,  gastro ,  Greek  for stomach,  entero or viscero , Greek for intestines,  gram , a Greek root meaning "to write".


An electrogastrogram (EGG), electroviscerogram (EVG) or a gastroenterogram are similar in principle to an  electrocardiogram  (ECG) in that sensors on the skin detect electrical signals indicative of muscular activity within. Where the electrocardiogram detects muscular activity in various regions of the heart, the electrogastrogram or electroviscerogram  detects the myoelectrical activity of the wave-like contractions of the stomach, intestines or other organs ( peristalsis ).


Walter C. Alvarez  discovered the EGG signal and pioneered early studies of electrogastrography in 1921–22. [ 1 ]


Motility  of  gastrointestinal tract  (GI tract) results from coordinated contractions of  smooth muscle , which in turn derive from two basic patterns of electrical activity across the  membranes  of smooth muscle cells— slow waves  and  action potentials . [ 2 ]  Slow waves are initiated by pacemakers—the  interstitial cells of Cajal  (ICC). Slow wave frequency varies in the different organs of the GI tract and is characteristic for that organ. They set the maximum frequency at which the muscle can contract:


The electrical activity or more properly termed myoelectrical activity of the GI tract can be subdivided into two categories: electrical control activity (ECA) and electrical response activity (ERA). ECA is characterized by regularly recurring electrical potentials, originating in the gastric pacemaker located in the  body of stomach .
The slow waves are not a direct reason of peristalsis of a GI tract, but a correlation between deviations of slow waves from norm and motility abnormalities however is proved. [ 5 ]


Recording of the Electrogastrogram can be made from either the gastrointestinal surface  mucosa ,  serosa , or the external skin surface. The cutaneous electrogastrography provides an indirect representation of the electrical activity, that has been demonstrated in numerous studies to exactly correspond to simultaneous recordings of the mucosa or serosa. Since it is much easier to perform, the cutaneous electrogastrography has been used most frequently. [ citation needed ]


Several EGG signals may be recorded from various standardized positions on the abdominal wall, However, for maximal accuracy and analysis it is important to select the one channel with the highest amplitude. Each channel usually consists of three  Ag-AgCl  electrodes. [ 6 ]   Recordings are made both fasting (usually 10–30 minutes) and after a stimulation meal (usually 30–60 minutes) with the patient lying quietly. The stimulation meal may vary but the most commonly used medium is room temperature water. Deviations from the normal frequency may be referred to as alterations in the gastric myoelectrical activity (GMA) or intestinal myoelectrical activity(IMA), These include: 1) bradygastria GMA, 2) tachygastria GMA, or 3) 3 cycle per minute hypernormal GMA or hyponormal GMA .


In normal individuals the power of the electrical signals increases after the meal. In patients with abnormalities of stomach and/or gastrointestinal motility, the rhythm often is irregular or there is no post-stimulation meal increase in electrical power.


Terms bradygastria and tachygastria are used at the description of deviations of frequency of an electric signal from slow waves are initiated by pacemaker in the stomach from normal frequency of 3 cycles per minute. [ citation needed ]


A  bradygastria  is defined, as decreased rate of myoelectrical activity in the stomach, as less than 2.5 cycles per minute for at least 1 minute.


A  tachygastria  is defined, as increased rate of myoelectrical activity in the stomach, as more than 3.75 cycles per minute for at least 1 minute.


A bradygastria and tachygastria may be associated with  nausea ,  gastroparesis ,  irritable bowel syndrome , and  functional dyspepsia . [ 7 ]


There are following  Current Procedural Terminology  (CPT) and  Healthcare Common Procedure Coding System  (HCPCS) codes (maintained by the  American Medical Association ) for cutaneous electrogastrography: [ 8 ]


An electrogastroenterography (EGEG) is based that different organs of a GI tract give different frequency slow wave.


EGEG electrodes are as much as possible removed from a stomach and an intestines—usually three electrodes are placed on the extremities. It allows to receive stabler and comparable results.


An electrogastroenterography analysis program calculate [ 9 ]


where  S(n)  – spectral components in the rank from st i  to fin i  (defined by received investigated range of this organ of GI tract) by  Discrete Fourier transform  of the electric signal from GI tract.


EGEG parameters for normal patients: [ 9 ]


Psychologists have performed psychophysiological studies to see what happens in the body during affective experiences.  Electrogastrograms have recently been used to test physiological  arousal , which was already determined by measures such as  heart rate ,  electrodermal skin responses , and changes in hormone levels in  saliva . [ 10 ]


Currently, a pattern of interest to psychologists is an increase in bradygastria, which is when electrical activity in the stomach drops to below 2 cpm resulting in a slower stomach rhythm, when exposed to  disgusting  stimuli, which may be a precursor to nausea and vomiting, both physiological responses to disgust. [ 11 ]  In this study, the presence of bradygastria was able to predict trait and state disgust, which no other physiological measure used in the study was able to detect. [ 11 ]  This abnormal myoelectrical activity is usually combined with other precursors to nausea and vomiting, such as increased salivary production, which further supports the idea that these rhythms show early signs of nausea and vomiting. These reactions are viewed as a way in which the body rejects unhealthy foods, [ 11 ]  which is linked with the view that disgust is an  evolutionary  adaptation to help humans avoid consuming toxic substances. [ 11 ] [ 12 ]


During  sham feeding  sessions of both appetizing and unappetizing foods, 3 cycles per minute (cpm) power was measured. During the sham feeding of appetizing foods, 3cpm power increased. This increase was not reported in the sham feeding of unappetizing foods. [ 12 ]  The researchers concluded that the presence of this pattern seems to mark the beginning of the body preparing for  digestion , and the absence of this pattern in the disgust condition could indicate that the body is readying to reject the food. [ 12 ]  The increase of 3cpm power is also linked with increased saliva and digestive juice production, all of which support the idea that this reflex, called the  cephalic-vagal reflex , [ 12 ]  is the precursor of digestion. The differential response to appetizing and unappetizing foods suggest that the body uses disgust as a cue to whether a food is good to eat and responds accordingly.


Another emotion with a bodily effect that can be measured by EGG is that of  stress .  When the body is stressed and engages in the  fight-or-flight response , blood flow is directed to the muscles in the arms and legs and away from the digestive system. This loss of blood flow slows the digestive system, and this slowing can be seen on the EGG. [ 13 ]  However, this response can vary from person to person and situation to situation. [ 13 ]


All of these examples are part of a larger theory of a  brain–gut connection . This theory states that the  vagus nerve  provides a direct link between the brain and the gut so that emotions can affect stomach rhythms and vice versa. [ 12 ] [ 13 ]  This idea originated in the mid-1800s when  Alexis St. Martin , a man with a gunshot-induced  fistula  in his abdomen, experienced lower secretions of digestive juices and a slower stomach emptying when he was upset. [ 13 ]  In this case, the emotions St. Martin was feeling affected his physiological reaction, but the reverse can also be true. In a study with  Crohn's disease  patients where patients and unaffected controls watched happy, frightening, disgusting, and saddening films, patients with active Crohn's disease had more responsive EGG (a greater physiological response) and reported feeling more aroused when feeling the negative emotions of disgust or sadness. [ 14 ]  This leads researchers to believe that increased physiological activation can influence increased experience of emotions. [ 14 ]   Another study published in 1943 that studied the fistulated man Tom discovered that if "Tom was fearful or depressed his gastic activity decreased but when he was angry or hostile his gastric activity increased". [ 13 ]  This finding is contrasted by an EGG study by Ercolani et al. who had subjects perform either difficult or easy mental arithmetic or puzzles. They found that new tasks slowed down the myoelectrical activity of the stomach, suggesting that  stress  tends to impede gastric activity and that this can be picked up on an EGG. [ 15 ]  While there is still much research to be done on the brain-gut connection, research thus far has indeed shown that your stomach does indeed churn differently when you are emotionally aroused, [ 16 ]  and this could be the basis of the gut feeling that many people describe experiencing.


In recent years, some research has been done about  gender differences  in the perception and experience of disgust.  One such study, upon presenting both male and female subjects with video clips designed to trigger disgust and found that although women reported feeling more disgust than men at these stimuli, the physiological responses did not show much difference. [ 10 ]  This could mean that, psychologically, women are more sensitive to disgust than men; however this assertion cannot be supported with physiological data. [ 10 ]  More research has to be done in this area to see if there are gender differences in the psychophysiological experience of disgust.


There are some limitations to the use of electrogastroenterography: [ citation needed ]


Electrogastrography or gastroenterography is used when a patient is suspected of having a motility disorder, which can be indicated by recurrent nausea and vomiting, signs that the stomach is not emptying food normally. The clinical use of electrogastrography has been most widely evaluated in patients with gastroparesis and functional dyspepsia.


An  endoscopy  is a procedure used in  medicine  to look inside the body. [ 1 ]  The endoscopy procedure uses an  endoscope  to examine the interior of a hollow organ or cavity of the body. Unlike many other  medical imaging  techniques, endoscopes are inserted directly into the organ.


There are many types of endoscopies. Depending on the site in the body and type of procedure, an endoscopy may be performed by either a doctor or a  surgeon . A patient may be fully conscious or  anaesthetised  during the procedure. Most often, the term  endoscopy  is used to refer to an examination of the upper part of the  gastrointestinal tract , known as an  esophagogastroduodenoscopy . [ 2 ]


For nonmedical use, similar instruments are called  borescopes .


Adolf Kussmaul  was fascinated by  sword swallowers  who would insert a sword down their throat without gagging. This drew inspiration to insert a hollow tube for observation; the next problem to solve was how to shine light through the tube, as they were still relying on candles and oil lamps as light sources. [ 3 ]


The term  endoscope  was first used on February 7, 1855, by engineer-optician Charles Chevalier, in reference to the  uréthroscope  of  Désormeaux , who himself began using the former term a month later. [ 4 ]  The self-illuminated endoscope was developed at  Glasgow Royal Infirmary  in  Scotland  (one of the first hospitals to have mains electricity) in 1894/5 by  John Macintyre  as part of his specialization in the investigation of the larynx. [ 5 ] [ failed verification ]


Endoscopy may be used to investigate symptoms in the  digestive system  including  nausea ,  vomiting ,  abdominal pain ,  difficulty swallowing , and  gastrointestinal bleeding . [ 6 ]  It is also used in diagnosis, most commonly by performing a biopsy to check for conditions such as  anemia , bleeding,  inflammation , and  cancers of the digestive system . [ 6 ]  The procedure may also be used for treatment such as  cauterization  of a bleeding vessel, widening a narrow esophagus, clipping off a polyp or removing a foreign object. [ 6 ]


Specialty   professional organizations  that specialize in digestive problems advise that many patients with  Barrett's esophagus  receive endoscopies too frequently. [ 7 ]  Such societies recommend that patients with Barrett's esophagus and no cancer symptoms after two biopsies receive biopsies as indicated and no more often than the recommended rate. [ 8 ] [ 9 ]


Health care providers can use endoscopy to review any of the following body parts:


Endoscopy is used for many procedures:


An endoscopy is a simple procedure that allows a doctor to look inside human bodies using an instrument called an endoscope.  A cutting tool can be attached to the end of the endoscope, and the apparatus can then be used to perform minor procedures such as tissue biopsies, banding of oesophageal varices or removal of polyps.


The main risks are infection, over-sedation, perforation, or a tear of the stomach or esophagus lining and bleeding. [ 10 ]  Although perforation generally requires surgery, certain cases may be treated with antibiotics and intravenous fluids. Bleeding may occur at the site of a biopsy or polyp removal. Such typically minor bleeding may simply stop on its own or be controlled by cauterisation. Seldom does surgery become necessary. Perforation and bleeding are rare during gastroscopy. Other minor risks include drug reactions and complications related to other diseases the patient may have. Consequently, patients should inform their doctor of all allergic tendencies and medical problems. Occasionally, the site of the  sedative  injection may become inflamed and tender for a short time. This is usually not serious and warm compresses for a few days are usually helpful. While any of these complications may possibly occur, each of them occurs quite infrequently. A doctor can further discuss risks with the patient with regard to the particular need for gastroscopy.


After the procedure, the patient will be observed and monitored by a qualified individual in the endoscopy room, or a recovery area, until a significant portion of the medication has worn off. Occasionally the patient is left with a mild sore throat, which may respond to saline gargles, or chamomile tea. It may last for weeks or not happen at all. The patient may have a feeling of distention from the insufflated air that was used during the procedure. Both problems are mild and fleeting. When fully recovered, the patient will be instructed when to resume their usual diet (probably within a few hours) and will be allowed to be taken home. Where sedation has been used, most facilities mandate that the patient be taken home by another person and that they not drive or handle machinery for the remainder of the day. Patients who have had an endoscopy without sedation are able to leave unassisted.


An  esophageal motility study  ( EMS ) or  esophageal manometry  is a test to assess  motor function  of the  upper esophageal sphincter  (UES), esophageal body and  lower esophageal sphincter  (LES). [ 1 ]


An EMS is typically done to evaluate suspected disorders of  motility  or  peristalsis  of the  esophagus . These include  achalasia ,  diffuse esophageal spasm ,  nutcracker esophagus  and  hypertensive lower esophageal sphincter . These disorders typically present with  dysphagia , or difficulty swallowing, usually to both solids and liquids even initially. Other patients with  spasm  disorders may have the test done to diagnose  chest pain  thought not to be of  cardiac  cause.


The test is not useful for anatomical disorders of the esophagus (that is, disorders that distort the anatomy of the esophagus), such as  peptic strictures  and  esophageal cancer .


A technician places a  catheter  into the nose and then guides it into the stomach. Once placed in the stomach lining, the catheter is slowly withdrawn, allowing it to detect pressure changes and to record information for later review. The patient will be asked at times to take a deep breath or to take some swallows of water. The degree of discomfort varies among patients. Patients are not  sedated  because sedatives would alter the functioning of the esophageal muscles. Overall the procedure takes about 45 minutes. After the procedure is complete, patients can usually resume their normal daily activities.


Upper gastrointestinal series  and their  fluoroscopic  counterparts use  x-rays  to image the swallowing motions.


Recently, [ when? ]   high resolution manometry  (HRM) has been developed that significantly reduces the procedure time (10 minutes versus 45 minutes with conventional manometry) and provides enhanced patient comfort. Newer catheters incorporate concurrent impedance with HRM.


In  gastroenterology ,  esophageal pH monitoring  is the current  gold standard  for diagnosis of  gastroesophageal reflux disease  (GERD). It provides direct physiologic measurement of acid in the  esophagus  and is the most objective method to document reflux disease, assess the severity of the disease and monitor the response of the disease to medical or surgical treatment. It can also be used in diagnosing  laryngopharyngeal reflux .


The importance of refluxed gastric contents in the  pathogenesis  of  GERD  was emphasized by Winkelstein who introduced the term " peptic   esophagitis " and by Bernstein and Baker who reported the symptom of  heartburn  following instillation of  hydrochloric acid  in the distal  esophagus  in what then became known as the  acid perfusion test . Formal measurement of  acid  in the  esophagus  was first described in 1960 by Tuttle. He used a glass  pH  probe to map the gastroesophageal pH gradient, and demonstrated a sharp gradient in normal subjects and a gradual, sloping gradient in patients with esophagitis. Four years later, Miller used an indwelling esophageal pH electrode to continuously measure esophageal and gastric pH for a period up to 12 hours. This technique required that the patient keep their hands immersed in saline to serve as a reference. Prolonged monitoring became feasible in 1974 when Johnson and  DeMeester  developed a dependable external reference electrode. [ 1 ]  Using this technique to monitor esophageal acid exposure patients for periods up to 24 hours, DeMeester and Johnson were able to identify the most important parameters of esophageal acid exposure, and they developed a composite pH score to quantify gastroesophageal reflux. The initial 24-hour pH studies required hospitalization until the introduction of  microcircuits  in the 1980s that allowed portable esophageal pH monitoring in an outpatient setting. [ citation needed ]


Gastroesophageal reflux disease  (GERD) is a common disease in western countries. In the  United States , 7% of the population experiences  heartburn  daily and 44% at least once a month. [ 2 ]   Heartburn  occurs when esophageal mucosa is exposed to the acidic gastric content, but the complaint of  heartburn  is not always a reliable guide to the presence of acid reflux in the esophagus. [ 3 ]  Further, only half of the patients with increased esophageal acid exposure will have  esophagitis . [ 4 ]   Therefore, the diagnosis of  gastroesophageal reflux disease  (GERD) on the basis of symptoms or endoscopic findings is problematic. [ citation needed ]


Although there remains no gold standard for the diagnosis of GERD, ambulatory esophageal  pH  monitoring can provide data to guide further evaluation and treatment of patients with GERD-associated symptoms. In the past, an indwelling nasoesophageal  catheter  was the only way to measure esophageal acid exposure. Because this method is associated with  nasal  and  pharyngeal  discomfort and  rhinorrhea , patients may have limited their activity and become more sedentary during the monitored period. [ 5 ]  This may have resulted in less acid reflux and a false negative test. A catheter-free radio  telemetric  system allows a longer period of monitoring and may be better tolerated. [ 6 ]


Esophageal pH monitoring is currently performed using one of the following three techniques:


The duration of the test is 24 hours in the first and second techniques and 48 hours for the Bravo capsule or more (96 hours) for OMOM capsule.


In assessment of distal esophageal pH, the sensor is placed 5 cm above the upper border of the  lower esophageal sphincter  (LES) determined by  esophageal manometry . To measure  proximal  esophageal acid exposure, the second sensor is placed 1-5 below the lower border of the  upper esophageal sphincter  (UES). The Bravo pH capsule is placed either transnasally based on manometric measurements, or following  endoscopy . In transnasal placement, the capsule is placed 5 cm above the upper border of the LES, and in endoscopic placement 6 cm above  the gastroesophageal junction . The same applies to OMOM pH monitoring capsule.


A reflux episode is defined as esophageal pH drops below four. Esophageal pH monitoring is performed for 24 or 48 hours and at the end of recording, a patient's tracing is analyzed and the results are expressed using six standard components. Of these 6 parameters, a pH score called  Composite pH Score  or  DeMeester Score  has been calculated, which is a global measure of esophageal acid exposure. A Demeester score > 14.72 indicates reflux. [ 7 ]


The widespread prescription of  proton pump inhibitors  (PPI) by primary care physicians has resulted in a change in pattern of GERD in patients who use these medications. Quite often gastroenterologist and foregut surgeons receive consultations to assess patients with persistent reflux symptoms despite the fact that patients is on acid suppression medications. This is due to the fact that symptoms of these patients are the results of weak acid or non-acid reflux.
In 1991  Silny  was the first investigator who described Multichannel Intraluminal Impedance (MII), a technique which detects intraesophageal bolus transport. This method is based on measuring the resistance to alternating current (i.e., impedance) of the content of the esophageal lumen. MII- pH monitoring was then developed by several clinical investigators. [ 8 ]  The clinical application of this technique is mainly in GERD patients who have persistent symptoms despite medical therapy. [ citation needed ]


Retrograde flow of gastric contents to the upper aerodigestive tract causes a variety of symptoms such as  cough ,  asthma  and  hoarseness . These respiratory manifestations of the reflux disease are commonly called  laryngopharyngeal reflux  (LPR) or extraesophegeal reflux disease (EERD). Distal esophageal pH monitoring has been used as an objective test to establish reflux as the cause of the atypical reflux symptoms, but its role in causally associating patients' symptoms to GERD is controversial. In an effort to improve diagnostic accuracy of testing, a catheter with two pH sensors has been used to measure the degree of esophageal acid exposure in both distal and proximal esophagus. The ideal location for pH measurement to confirm the diagnosis of the laryngopharyngeal reflux is the  pharynx  and new studies have focused on the development of a new pH sensor which can function in the challenging environment of the oropharynx. [ 9 ]


Esophagogastroduodenoscopy  ( EGD ) or  oesophagogastroduodenoscopy  ( OGD ), also called by  various other names , is a  diagnostic   endoscopic  procedure that visualizes the upper part of the  gastrointestinal tract  down to the  duodenum . It is considered a  minimally invasive procedure  since it does not require an  incision  into one of the major body cavities and does not require any significant recovery after the procedure (unless  sedation  or  anesthesia  has been used). However, a  sore throat  is common. [ 1 ] [ 2 ] [ 3 ]


The words  esophagogastroduodenoscopy  (EGD;  American English ) and  oesophagogastroduodenoscopy  (OGD;  British English ; see  spelling differences ) are pronounced  / ɪ ˌ s ɒ f ə ɡ oʊ ˌ ɡ æ s t r oʊ ˌ d ( j ) uː oʊ d ɪ ˈ n ɒ s k ə p i / . It is also called  panendoscopy  (PES) and  upper GI endoscopy . It is also often called just  upper endoscopy ,  upper GI , or even just  endoscopy ; because EGD is the most commonly performed type of endoscopy, the ambiguous term  endoscopy  is sometimes informally used to refer to EGD by default. The term  gastroscopy  literally focuses on the stomach alone, but in practice, the usage overlaps.


The complication rate is about 1 in 1000. [ 4 ]  They include:


When used in  infants , the esophagogastroduodenoscope may compress the  trachealis muscle , which narrows the  trachea . [ 5 ]  This can result in reduced airflow to the  lungs . [ 5 ]  Infants may be  intubated  to make sure that the trachea is fixed open. [ 5 ]


Problems of gastrointestinal  function  are usually not well diagnosed by endoscopy since  motion  or  secretion  of the gastrointestinal tract is not easily inspected by EGD. Nonetheless, findings such as excess fluid or poor motion of the gut during endoscopy can be suggestive of disorders of function.  Irritable bowel syndrome  and  functional dyspepsia  are not diagnosed with EGD, but EGD may be helpful in excluding other diseases that mimic these common disorders. [ citation needed ]


The tip of the endoscope should be lubricated and checked for critical functions including tip angulations, air and water suction, and image quality.


The patient is kept  NPO (nil per os) or NBM (nothing by mouth)  for at least 4 hours before the procedure. Most patients tolerate the procedure with only  topical anesthesia  of the  oropharynx  using  lidocaine  spray. However, some patients may need sedation and the very anxious/agitated patient may even need a general anesthetic.  Informed consent  is obtained before the procedure. The main risks are bleeding and perforation. The risk is increased when a biopsy or other intervention is performed.


The patient lies on their left side with the head resting comfortably on a pillow. A mouth-guard is placed between the teeth to prevent the patient from biting on the endoscope. The endoscope is then passed over the tongue and into the oropharynx. This is the most uncomfortable stage for the patient. Quick and gentle manipulation under vision guides the endoscope into the esophagus. The endoscope is gradually advanced down the esophagus making note of any pathology. Excessive  insufflation  of the stomach is avoided at this stage. The endoscope is quickly passed through the stomach and through the  pylorus  to examine the first and second parts of the  duodenum . Once this has been completed, the endoscope is withdrawn into the stomach and a more thorough examination is performed including a J-maneuver. This involves retroflexing the tip of the scope so it resembles a 'J' shape in order to examine the  fundus  and gastroesophageal junction. Any additional procedures are performed at this stage. The air in the stomach is aspirated before removing the endoscope. Still  photographs  can be made during the procedure and later shown to the patient to help explain any findings.


In its most basic use, the endoscope is used to inspect the internal anatomy of the digestive tract. Often inspection alone is sufficient, but  biopsy  is a valuable adjunct to endoscopy. Small biopsies can be made with a pincer (biopsy  forceps ) which is passed through the scope and allows sampling of 1 to 3 mm pieces of tissue under direct vision. The intestinal mucosa heals quickly from such biopsies.


Clinical practice varies with respect to routine biopsy for histological analysis of the examined upper gastrointestinal system. A rapid urease test is quick, easy, and cost-effective screening for Helicobacter pylori infection.


Faecal calprotectin  ( or   fecal calprotectin ) is a  biochemical measurement  of the protein  calprotectin  in the  stool . Elevated faecal calprotectin indicates the migration of  neutrophils  to the intestinal  mucosa , which occurs during intestinal inflammation, including inflammation caused by  inflammatory bowel disease .  Under a specific clinical scenario, the test may eliminate the need for invasive  colonoscopy  or radio-labelled  white cell  scanning.


Calprotectin is a 24 kDa  dimer  of  calcium  binding proteins  S100A8  and  S100A9 . [ 1 ]   The complex accounts for up to 60% of the soluble protein content of the  neutrophil   cytosol . [ 2 ] [ 3 ]   In vitro  studies show that calprotectin has  bacteriostatic  and  fungistatic  properties, that arise from its ability to sequester  manganese  and  zinc . [ 1 ]   Calprotectin has two  transition metal  binding sites that form at the interface of the S100A8 and S100A9 monomers, and metal sequestration by calprotectin has been shown to be calcium dependent. [ 1 ]  The complex is resistant to  enzymatic  degradation, and can be easily measured in  faeces . [ 4 ]


The main diseases that cause an increased excretion of faecal calprotectin are   inflammatory bowel diseases  (IBD),  coeliac disease ,  infectious colitis ,  necrotizing enterocolitis  in infants, intestinal  cystic fibrosis  and  colorectal cancer . [ 6 ] [ 7 ]


Although a relatively new test, faecal calprotectin is regularly used as indicator for IBD during treatment and as a diagnostic marker. [ 6 ]   IBD are a group of conditions that cause a  pathological   inflammation  of the  bowel  wall.  Crohn's disease  and  ulcerative colitis  are the principal types of inflammatory bowel disease. Inflammatory processes result in an influx of neutrophils into the bowel  lumen . [ 8 ]  Since calprotectin comprises as much as 60% of the soluble protein content of the cytosol of neutrophils, it can serve as a marker for the level of intestinal inflammation. [ 9 ]  Measurement of faecal calprotectin has been shown to be strongly correlated with 111- indium -labelled  leucocytes  – considered the gold standard measurement of  intestinal  inflammation. [ 10 ]


Levels of faecal calprotectin are usually normal in patients with  irritable bowel syndrome  (IBS). [ 11 ] [ better source needed ]  In untreated coeliac disease, concentration levels of faecal calprotectin correlate with the degree of  intestinal mucosal lesion  and normalize with a  gluten-free diet . [ 6 ]
High fecal calprotectin is a common finding among hospitalized coronavirus disease 2019 ( COVID-19 ) patients, especially those with  SARS-CoV-2  fecal shedding. [ 12 ]


Faecal calprotectin is measured using  immunochemical  techniques such as  ELISA  or  immunochromatographic  assays. The  antibodies  used in these assays target specific  epitopes  of the calprotectin molecule. [ 8 ]


Increased faecal calprotectin may be indicative of intestinal tuberculosis or pulmonary tuberculosis. [ 13 ]


Although faecal calprotectin correlates significantly with disease activity in people with confirmed IBD, faecal calprotectin can be false-positive if the laboratory uses low calprotectin cut-off levels. [ 11 ]  Most importantly, intake of  non-steroidal anti-inflammatory drugs  (aspirin included) increases calprotectin values, possibly due to the associated induced  enteropathy . [ 14 ]


Fecal occult blood  ( FOB ) refers to  blood  in the  feces  that is not visibly apparent (unlike other types of  blood in stool  such as  melena  or  hematochezia ). A fecal occult blood test (FOBT) checks for hidden (occult) blood in the stool (feces). [ 1 ]


The American College of Gastroenterology has recommended the abandoning of gFOBT testing as a colorectal cancer screening tool, in favor of the  fecal immunochemical test  (FIT). [ 2 ]   The newer and recommended tests look for  globin ,  DNA , or other blood factors including  transferrin , while conventional  stool guaiac tests  look for  heme .


Fecal occult blood testing (FOBT), as its name implies, aims to detect subtle blood loss in the  gastrointestinal tract , anywhere from the  mouth  to the  colon . Positive tests ("positive stool") may result from either  upper gastrointestinal bleeding  or  lower gastrointestinal bleeding  and warrant further investigation for  peptic ulcers  or a  malignancy  (such as  colorectal cancer  or  gastric cancer ). The test does not directly detect  colon cancer  but is often used in clinical  screening  for that disease. It can also be used to look for active occult blood loss in  anemia [ 3 ]  or when there are gastrointestinal symptoms. [ 4 ]


An estimated 1–5% of large tested populations have a positive fecal occult blood test. [ citation needed ]  Of those, about 2–10% have cancer, while 20–30% have  adenomas .  Screening  methods for colon cancer depend on detecting either precancerous changes such as certain kinds of polyps or on finding early and thus more treatable cancer. The extent to which screening procedures reduce the risk of gastrointestinal cancer or deaths depends on the rate of precancerous and cancerous disease in that population. gFOBT (guaiac fecal occult blood test) and flexible sigmoidoscopy screening have each shown benefit. Other colon cancer screening tools such as iFOBT (immunochemical fecal occult blood test) or colonoscopy are also included in guidelines. [ 5 ]


In 2009, the  American College of Gastroenterology  (ACG) suggested that colon cancer screening modalities that are also directly preventive by removing precursor lesions should be given precedence, and prefer a  colonoscopy  every ten years in average-risk individuals, beginning at age 50. [ 2 ]  The ACG suggests that cancer detection tests such as any type of FOB are an alternative that is less preferred, and if a colonoscopy is declined, the FIT (fecal immunochemical test, or iFOBT) should be offered instead. The 2017 US Multi-Society Task Force (MSTF)'s recommended first-tier tests are a colonoscopy every 10 years or annual FIT test. [ 6 ]  If FIT is utilized, proper steps must be taken to ensure appropriate use and follow-up of abnormal FIT results. [ 7 ]  FIT tests however are not that useful in picking up adenomas, even when advanced. [ 8 ]


The  United States Preventive Services Task Force  (USPSTF)'s 2016 recommendation, instead of emphasizing specific screening approaches, has instead chosen to highlight that there is convincing evidence that colorectal cancer screening substantially reduces deaths from the disease among adults aged 50 to 75 years and that not enough adults are using this effective preventive intervention. [ 9 ]  The ACG and MSTF also included CT colonography every five years, and fecal DNA testing as considerations. All three recommendation panels recommended replacing any older low-sensitivity, guaiac-based fecal occult blood testing (gFOBT) with either newer high-sensitivity guaiac-based fecal occult blood testing (hs gFOBT) or fecal immunochemical testing (FIT). MSTF looked at six studies that compared high-sensitivity gFOBT (Hemoccult SENSA) to FIT, and concluded that there was no clear difference in overall performance between these methods.


The English  National Health Service  (NHS) introduced a Bowel Cancer Screening Program in 2006. [ 10 ]  It is now offered to patients aged 60–74 years. In 2019 FIT was introduced as the primary screening test in England and Wales, replacing gFOBt.  [ 11 ] [ 12 ]  However, research carried out in the UK has suggested that the FIT threshold for further investigation is set at a point that may miss more than half of bowel cancer cases and only identifies one in four high-risk polyps. [ 13 ] [ 14 ]


The American College of Gastroenterology has recommended the abandoning of gFOBT testing as a colorectal cancer screening tool, in favor of the fecal immunochemical test. [ 2 ]  Though the FIT test is preferred, even the guaiac FOB testing of average risk populations may have been sufficient to reduce the mortality associated with  colon cancer  by about 25%. [ 15 ]  With this lower efficacy, it was not always cost-effective to screen a large population with gFOBT. [ 16 ] [ 17 ] [ 18 ] [ 19 ]


If colon cancer is suspected in an individual (such as in someone with an unexplained  anemia ), fecal occult blood tests may not be clinically helpful. If a doctor suspects colon cancer, more rigorous investigation is necessary, whether or not the test is positive. [ citation needed ]


In 2006, the Australian Government introduced the National Bowel Cancer Program which has been updated several times since; targeted screening will be done of all Australians aged from 50 to 74 by 2020. Cancer Council Australia recommended that FOBT should be done every two years. People over 50 not yet eligible for the national program can arrange with their doctor for an FOBT. [ 20 ]
The  Canadian Cancer Society  recommends that men and women aged 50 and over have an FOBT at least every two years. [ 21 ]
In colon cancer screening, using only one sample of feces collected by a doctor performing a  digital rectal examination  is discouraged. [ 22 ]


The use of the  M2-PK Test  is encouraged over gFOBT for routine screening, as it may pick up tumors whether or not they are bleeding. [ 23 ]  It is able to detect 80 percent of colorectal cancers and 44 percent for adenoma > 1 centimeter, while gFOBT picks up 13 to 50 percent of colorectal cancers. [ 23 ]


Gastrointestinal bleeding  has many potential sources, and positive results usually result in further testing for the bleeding site, usually looking for  lower gastrointestinal bleeding  before  upper gastrointestinal bleeding  causes unless there are other clues. [ 24 ]  Colonoscopy is usually preferred to computerized tomographic colonography. [ 25 ]


A positive test can result from  upper gastrointestinal bleeding  or  lower gastrointestinal bleeding . The common causes are:


In the event of a positive fecal occult blood test, the next step in the workup is a form of visualization of the gastrointestinal tract by one of several means:


The use of an FOBT for bleeding from the mouth, nose, esophagus, lungs, stomach and the initial portion of the small intestine, while the same as fecal testing, is discouraged, due to technical considerations including poorly characterized test performance characteristics such as sensitivity, specificity, and analytical interference. [ 29 ]  However, chemical confirmation that coloration is due to blood rather than coffee, beets, medications, or food additives can be of significant clinical assistance.


Gastrointestinal (GI) complaints and low-intensity GI bleeding frequently occur in marathon runners. [ 30 ]  Strenuous exercise, particularly in elite athlete runners and less frequently in other exercise activities, can cause acute incapacitating gastrointestinal symptoms including heartburn, nausea, vomiting, abdominal pain, diarrhea and gastrointestinal bleeding. [ 31 ]  Approximately one third of endurance runners experience transient but exercise-limiting symptoms, and repetitive gastrointestinal bleeding occasionally causes iron deficiency and anaemia. [ 32 ] [ 33 ]  Runners can sometimes experience significant symptoms including  hematemesis . [ 34 ]  Exercise is associated with extensive changes in gastrointestinal (GI) tract physiology, including diversion of blood flow from the GI tract to muscles and lungs, decreased GI absorption and small intestinal motility, increased colonic transit, neuroimmunoendocrine changes in hormones and peptides such as  vasoactive intestinal peptide ,  secretin  and peptide-histidine-methionine. [ 35 ]  Substantial changes occur in stress hormones including cortisol, in circulating concentrations and metabolic behavior of various  leucocytes , and in  immunoglobulin  levels and  major histocompatibility complex  expression. [ 36 ]  Symptoms can be exacerbated by dehydration or by pre-exercise ingestion of certain foods and  hypertonic  liquids, and lessened by adequate training. [ 35 ]


Ingestion of 800   mg of  cimetidine  two hours before running a marathon did not significantly affect the frequency of gastrointestinal symptoms or occult gastrointestinal bleeding. [ 37 ]  Conversely, 800   mg of cimetidine 1 hr before the start and again at 50 miles of a 100-mile running race substantially decreased GI symptoms and post-race guaiac test positivity but did not affect race performance. [ 38 ]


There are four methods in clinical use to test for occult blood in feces. These look at different properties, such as  antibodies ,  heme ,  globin , or  porphyrins  in blood, or at  DNA  from cellular material such as from lesions of the intestinal mucosa.


Additional methods of looking for occult blood are being explored, including  transferrin  dipstick [ 48 ]  and stool  cytology . [ 49 ]


The estimates for test performance characteristics are based on comparison with a variety of  reference methods  including 51-chromium studies, [ citation needed ]  analytical recovery studies in spiked stool samples, analytical recovery after ingestion of autologous blood, rarer studies of carefully quantified blood instilled at bowel surgery  [ citation needed ] , as well as other research approaches. [ citation needed ]  Additionally, clinical studies look at a variety of additional factors.


In healthy people about 0.5 to 1.5   ml of blood escapes blood vessels into the stool each day. [ 50 ] [ 51 ] [ 52 ]  Significant amounts of blood can be lost without producing visible blood in the stool, estimated as 200   ml in the stomach, [ 53 ]  100   ml in the duodenum, and lesser amounts in the lower intestine. Tests for occult blood identify lesser blood loss.


Fecal immunochemical testing (FIT) can identify as little as 0.3   ml of daily blood in the stool; yet this test threshold does not cause undue false positives from normal upper intestinal blood leakage because it does not detect occult blood from the stomach and upper small intestine. Thus, the FIT test is much more specific for bleeding from the colon or lower gastrointestinal tract than alternatives. [ 54 ]  The detection rate of the test decreases if the time from sample collection to laboratory processing is delayed; processing the sample in under five days from collection is recommended. [ 55 ]  It does not appear to be affected by aspirin, anticoagulants, or nonsteroidal anti-inflammatory drugs. [ 56 ]


Stool guaiac test  for fecal occult blood (gFOBT) sensitivity varies depending on the site of bleeding. Moderately sensitive gFOBT can pick up a daily blood loss of about 10   ml (about two teaspoonfuls), and higher sensitivity gFOBT can pick up lesser amounts, requires at least 2   ml to become positive. The sensitivity of a single-stool guaiac test to pick up bleeding has been quoted at 10 to 30%, but if a standard three tests are done as recommended the sensitivity rises to 92%. [ 57 ]  Reduced patient compliance with the collection of three samples hampers the usefulness of this test. Further discussion of sensitivity and specificity issues that relate particularly to the guaiac method is found in the  stool guaiac test  article.


Fecal  porphyrin  quantification by HemoQuant can yield a  false positive  result due to exogenous blood and various porphyrins. HemoQuant is the most sensitive test for upper gastrointestinal bleeding and therefore may be most appropriate fecal occult blood test to use in the evaluation of iron deficiency. [ 58 ]  It is advisable to stop ingesting red meat and aspirin for three days prior to specimen collection. [ 59 ]  False positives can occur with myoglobin, catalase, or protohemes [ 60 ]  and in certain types of porphyria. [ citation needed ]


Fecal DNA tests as of 2008 had not been studied enough to support widespread use. [ 61 ]


Safety regulations from US accreditor  the Joint Commission  may have unintentionally decreased digital rectal examination and FOBT in hospital settings such as Emergency Departments. [ 62 ] [ 63 ]


In  medicine , the  fluid wave test  or  fluid thrill test  is a test for  ascites  (free fluid in the peritoneal cavity). It is performed by having the patient (or a colleague) push their hands down on the midline of the abdomen. The examiner then taps one flank, while feeling on the other flank for the tap. The pressure on the midline prevents vibrations through the abdominal wall while the fluid allows the tap to be felt on the other side.
The result is considered positive if tap can be felt on the other side. However, even with the midline pressure, transmission through the skin must be excluded.
A positive fluid wave test indicates that there is a free fluid (ascites) in the abdomen. When one side of the abdomen is pressed, the other side may also be painful due to the transfer of the fluid in it.


Forrest classification  is a classification of  upper gastrointestinal hemorrhage  used for purposes of comparison and in selecting patients for  endoscopic treatment . [ 1 ]


Acute hemorrhage


Signs of recent hemorrhage


Lesions without active bleeding


Forrest's classification is instrumental when stratifying patients with upper gastrointestinal hemorrhage into high and low risk categories for  mortality . It is also a significant method of prediction of the risk of rebleeding and very often is used for evaluation of the
endoscopic intervention modalities. [ 3 ]  A prospective  controlled study  revealed that "Forrest criteria are essential for proper planning of endoscopic therapy and urgent surgery in bleeding peptic ulcers". [ 4 ]


The classification was first published by J.A. Forrest,  et al.  in the  Lancet  in 1974. [ 5 ]


Functional Lumen Imaging Probe  ( FLIP ) is a test used to evaluate the function of the  esophagus , by measuring the dimensions of the esophageal lumen using  impedance   planimetry . Typically performed with sedation during  upper endoscopy , FLIP is used to evaluate for  esophageal motility disorders , such as  achalasia ,  diffuse esophageal spasm , etc. [ 1 ]


FLIP is most often performed immediately following upper endoscopy (EGD). [ 1 ]  EGD helps to rule out a mechanical obstruction as a cause for symptoms, and also provides an estimation on the distance from the incisors to the EGJ. [ 1 ]


FLIP uses impedance planimetry to measure the cross sectional area of the esophageal lumen. [ 1 ]  The FLIP device consists of a balloon that encases a catheter with multiple pairs of impedance electrodes. Two catheter configurations are available, which are 8 cm and 16 cm in length. The 8 cm catheter includes 16 sensors spaced 0.5 cm apart, and is used to evaluate esophagogastric junction (EGJ) distensibility and CSA. [ 1 ]  Alternatively, the 16 cm catheter has 16 sensors spaced 1 cm apart, and may be used to evaluate contractility via secondary peristalsis patterns, in addition to evaluating the esophagogastric junction (EGJ). [ 1 ]


Following upper endoscopy, the balloon is inserted into the esophagus and the balloon is distended with a fluid with known properties (e.g. conductivity and volume). [ 1 ]  Each electrode then measures impedance, and a single pressure sensor at the end of the device measures pressure within the balloon. [ 1 ]


The distensibility index (DI) is the most studied and most helpful result obtained with FLIP testing. [ 1 ]  The normal DI ranges from 3.1 to 9.0 mm2 per mmHg. [ 1 ]  As the balloon is distended, the results of secondary esophageal secondary contractions may be seen via FLIP panometry. [ 1 ]  Possible results may include: repetitive anterograde contractions (a normal finding), repetitive retrograde contractions (abnormal), absent contractility, and other abnormalities. [ 1 ]


FLIP may be used for several indications to evaluate esophageal symptoms, such as dysphagia, chest pain, or regurgitation, or to assess response to treatment. FLIP is used to evaluate for esophageal motility disorders, such as  achalasia ,  diffuse esophageal spasm , etc. [ 1 ]  FLIP may be used as a complementary or alternative to esophageal manometry for evaluating esophageal outflow obstructive disorders, including achalasia. FLIP may be used as a complementary test for barium esophagram for evaluating esophageal outflow obstructive disorders. FLIP may be used to assess the effect of treatment for achalasia. [ citation needed ]


FLIP is recommended to further evaluate suspected  esophagogastric junction outflow obstruction  (EGJOO) where the manometry is normal or borderline. [ 2 ]  FLIP measurements may be used to guide intraoperative reflux surgery, or to assess the degree of fibrostenotic disease from eosinophilic esophagitis. [ 1 ] [ 3 ]  FLIP may be used to guide endoscopic dilation of esophageal strictures. [ 1 ]


While recommendations exist for its use, the evidence supporting the use of FLIP is of very low quality and further research would be useful in more clearly defining its role. [ 4 ] [ 5 ]


Early development of impedance planimetry for evaluating the gastrointestinal tract began in the 1980s. [ 6 ]  FLIP was first developed with a short balloon catheter, which measures distension across the esophagogastric junction. [ 7 ]  A second generation device was later released, which measures secondary peristalsis proximal to the EGJ. [ 7 ]


Given Imaging Ltd.  ( Hebrew : גיוון אימג'ינג) is an Israeli  medical technology  company that manufactures and markets diagnostic products for the visualization and detection of disorders of the  gastrointestinal tract . Until March 2014, it was  dual-listed  on both the  NASDAQ  and the  Tel Aviv Stock Exchange , where it was a component of the  TA-100 Index  and the  TA BlueTech Index . In March 2014 it was acquired by  Covidien  and became a private company. In 2015  Covidien  was purchased by  Medtronic .


Given Imaging pioneered the  capsule endoscopy  technology and has also developed capsule-based pH monitoring. [ 1 ]  Through Sierra Scientific Instruments, a subsidiary, Given Imaging also provides an array of diagnostic modalities including high-resolution manometry and ambulatory reflux monitoring. Given Imaging's technology is currently marketed in over 60 countries.


Given Imaging was founded in 1998 by Gavriel Meron and  Rafael Development Corporation  (RDC) Ltd. based on the purchase of an early patent from Rafael Advanced Defense Systems Ltd. Initial funding for the company was provided by  Elron Electronic Industries , Israel's leading technology holding company, in cooperation with Rafael. Today,  Elron  still holds 28% Given Imaging's shares. [ 2 ]  The idea for the solution was developed by Dr. Iddan, while working in the missile division of Rafael, where he envisioned that missile technology could be miniaturized to create a medical product. [ 3 ]


The company's first  capsule endoscopy  products was named M2A capsule and received it  CE marking  in May 2001 and in August 2001 was cleared
by the  US Food and Drug Administration  (FDA) for visualization of abnormalities of the small intestine [ 4 ]  The capsule uses a radio developed for Given by Zarlink Semiconductor's medical team in San Diego and Jarfalla, Sweden.


In October 2001, Given Imaging had an  Initial public offering  on  NASDAQ  under ticker GIVN.) [ 5 ]  In September 2004, M2A capsule re-branded PillCam SB(R).


In March 2004, Given Imaging became a member of the  Tel Aviv Stock Exchange [ 6 ]


In November 2004, US FDA clears PillCam(R) ESO for the esophagus


In May 2006, US FDA clears Agile Patency System [ 7 ]


In October 2006, PillCam COLON was cleared for marketing in the European Union (CE Mark) [ 8 ]


In December 2008, Given Imaging acquired Bravo pH Monitoring System(R)


In May 2009, 1 millionth PillCam capsule was sold [ 9 ]


In September 2009, PillCam COLON 2 receives CE Mark [ 10 ]


In July 2012, Given Imaging's  capsule endoscopy  featured in a live broadcast on the  BBC , when the reporter Michael Mosley spent the day as an exhibit at  the Science Museum  in London, after swallowing a PillCam which transmitted live pictures to a public screen. [ 11 ]


In February 2014, 100% of Given Imaging's shares were purchased by  Covidien , making it a  Private Company  fully owned by Covidien. As a result, its shares are no longer traded neither in NASDAQ nor in TASE [ 12 ]


In 2015  Covidien  was purchased by  Medtronic


PillCam SB is a tool for visualization of the entire small bowel and detection of small bowel abnormalities.  No sedation is needed, however bowel prep is needed. A liquid bowel prep is consumed before the procedure emptying the bowel completely, this allows clear photos to be taken. [ 13 ]


PillCam ESO provides a method for visualization of the esophagus. [ 14 ]


PillCam COLON 2 is complementary to traditional colonoscopy and is used for patients who have received incomplete colonoscopy, are contraindicated for colonoscopy or are unwilling to undergo traditional colonoscopy. [ citation needed ]


The PillCam CROHN’S system offers direct visualization of the entire small bowel and colonic mucosa with a noninvasive procedure.


In May 2010, Given Imaging released a new manually guided GI scope based on PillCam swallowable devices. In cases where patient anatomy does not allow for natural passage of large tablets the size of traditional PillCams, the PillCam Express can be delivered through the stomach and into the small intestine with help of an endoscope and a proprietary balloon deployment mechanism. [ 15 ]


The Bravo pH Monitoring System is a catheter-free ambulatory pH test. [ 16 ]   Ambulatory pH testing is considered the gold standard for pH measurement and monitoring of gastric reflux, helping clinicians manage gastroesophageal reflux disease (GERD).  Featuring data collection for up to 96 hours, Bravo allows patients to maintain their regular diets and activities, accurately reflecting normal physiologic conditions. [ citation needed ]


In April 2010, Given Imaging acquired Sierra Scientific Instruments. [ 17 ]


The company's corporate headquarters, research and development laboratories, and manufacturing facilities are located in  Yokneam , Israel. [ 18 ] [ 19 ]  It maintains offices in  Duluth, Georgia  and  Heerlen ,  Netherlands . Additional sales and marketing offices are located in  France ,  Japan ,  Australia , and  Singapore . The company also has a plant in  Ireland . [ citation needed ]


Given Imaging's wholly owned subsidiary, Sierra Scientific Instruments, is located in  Los Angeles , California, with manufacturing operations in Vietnam. [ citation needed ]


The  Glasgow-Blatchford bleeding score  ( GBS ) is a  screening tool  to assess the likelihood that a person with an acute  upper gastrointestinal bleeding  (UGIB) will need to have medical intervention such as a  blood transfusion  or  endoscopic  intervention. [ 1 ]  The tool may be able to identify people who do not need to be admitted to hospital after a UGIB. Advantages of the GBS over the  Rockall score , which assesses the risk of death in UGIB, include a lack of  subjective  variables such as the severity of systemic diseases and the lack of a need for  oesophagogastroduodenoscopy  (OGD) to complete the score, a feature unique to the GBS.


It was developed in 2000 by Oliver Blatchford (born 24 August 1954) at the  Glasgow Royal Infirmary .


In a controlled study, 16% of people presenting with UGIB had a GBS score of "0", considered low. Among this group there were no deaths or interventions needed and people were able to be effectively treated in an outpatient setting. [ 2 ]


The score is calculated using the table below:


In the validation group, scores of 6 or more were associated
with a greater than 50% risk of needing an intervention.


Score is equal to "0" if the following are all present: [ citation needed ]


Klemm's sign , also known as  air cushion sign , [ 1 ]  is a sign of chronic appendicitis.


A  lower gastrointestinal series  is a medical procedure used to examine and diagnose problems with the human  colon  of the  large intestine .  Radiographs  ( X-ray  pictures) are taken while  barium sulfate , a  radiocontrast agent , fills the colon via an  enema  through the  rectum .


The term  barium enema  usually refers to a lower gastrointestinal series, although enteroclysis (an  upper gastrointestinal series ) is often called a small bowel barium enema.


For any suspected large bowel disease,  colonoscopy  is the investigation of choice because tissue sample can be taken for investigation.  Virtual colonoscopy  (also known as CT colonography) is another preferred investigation, provided that facilities and expertise are available. Virtual colonoscopy also avoids the risk of total blockage of any stricture in the large bowel due to barium impaction. [ 1 ]  Some conditions are absolutely contraindicated for barium enema namely:  toxic megacolon ,  pseudomembranous colitis , and recent history rigid endoscopy of the large bowel in the past five days and recent history of flexible endoscopy in the past 24 hours. This is because, rigid endoscopy tends to use larger biopsy forceps to take tissue samples from the bowel wall while flexible endoscopy uses small biopsy forceps to take superficial samples. [ 1 ]  For those with incomplete bowel preparation, the subject can return the next day or the day after next to repeat the procedure. If barium meal was performed recently, then it is advised to wait for another seven to ten days before repeating the procedure. Some frail subject may not be suitable for barium meal. [ 1 ]


Barium enemas are most commonly used to check bowel health; they can help diagnose and evaluate the extent of inflammatory bowel diseases such as  ulcerative colitis  and  Crohn's disease .   Polyps  can be seen, though not removed during the exam like with a  colonoscopy —they may be cancerous. Other problems such as  diverticulosis  (small pouches formed on the colon wall that can become inflamed) and  intussusception  can be found (and in certain cases the test itself can treat intussusception).  An acute  appendicitis  or twisted loop of the bowel may also be seen. If the picture is normal a functional cause such as  irritable bowel syndrome  (IBS) may be considered.


In a healthy colon, barium should fill the colon uniformly and show normal bowel contour, patency (should be freely open), and position.


Additional conditions under which the test may be performed:


Barium enema can be done in two ways, namely  double contrast  and single contrast methods. Double contrast (where air is inflated into the bowel after excess barium are drained through anus) is useful in visualising mucosal pattern. For single contrast study (whole bowel is filled up with barium without inflating any air), it is used to visualise any obstruction in the large bowel, and it is used in children where visualisation of mucosal pattern is not needed. Barium enema is also used to reduce an  intussusception  where this disorder is more commonly found in children. [ 1 ]  500 ml of Polibar 150% ( barium sulfate suspension ) is used to perform this study. Subject should be fasted and Picolax ( sodium picosulfate ) is taken orally to empty the bowels before barium enema procedure. [ 1 ]


This test may be done in a hospital or clinic. The individual lies on the X-ray table and a preliminary X-ray is taken. The individual is then asked to lie on their side while a well lubricated  enema  tube is inserted into the  rectum . As the enema enters the body, the individual might have the sensation that they need to have a bowel movement. The barium sulfate, a  radiodense  (shows as white on X-ray)  contrast medium , flows through the rectum into the  colon . A large balloon at the tip of the enema tube may be inflated to help keep the barium sulfate inside. The flow of the barium sulfate is monitored by the health care provider on an X-ray  fluoroscope  screen (like a TV monitor). Air may be puffed into the colon to distend it and provide better images (often called a "double-contrast" exam). If air is used, the enema tube will be reinserted if it had been removed and a small amount of air will be introduced into the colon, and more X-ray pictures are taken.


The individual is usually asked to move to different positions and the table is slightly tipped to get different views.


If there is a suspected  bowel perforation , a water-soluble  contrast agent  (such as  diatrizoate ) is used instead of barium.  The procedure is otherwise very similar, although the images will be of poorer quality. If a perforation exists, the contrast will leak from the bowel to the  peritoneal cavity ; water-soluble material is less obscuring compared to barium should  an abdominal incision  to remove the contrast be necessary.


Assume that the x-ray tube is moving above the table and the x-ray film is moving below the table (overcouch): [ 1 ]
The subject lying supine to give AP (anteroposterior) view of all the bowels. [ 1 ]
Left lateral view of rectum is to view the rectum from lateral position. [ 1 ]
Right anterior oblique (RAO) position is to view the caecum, ascending colon, right hepatic flexure and sigmoid colon without overlapping of other bowels. [ 1 ]
Left anterior oblique (LAO) position is to view the splenic flexure without overlapping of other bowels. [ 1 ]
Left posterior oblique (LPO) position is to view the sigmoid colon without overlapping of other bowels. [ 1 ]
Hampton's view (prone caudal view) of rectosigmoid colon is taken when the subject is in prone position with the X-ray tube tilted towards the feet at 30 degrees. This is to separate out the loops of sigmoid colon. [ 2 ]


Other views include right and left decubitus views [ 1 ]


X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits. Pregnant women and children are more sensitive to the risks of ionizing radiation.


A more serious risk is a bowel perforation.


CT scans  and  ultrasounds  are now the tests of choice for the initial evaluation of abdominal masses, and colonoscopies are becoming the standard for routine colon screening for those over age 50 or with a familial history of polyps or colon cancer, although it is not uncommon for a barium enema to be done after a colonoscopy for further evaluation.


Narrow-band imaging  is an imaging technique for  endoscopic  diagnostic medical tests, where light of specific blue and green  wavelengths  is used to enhance the detail of certain aspects of the surface of the  mucosa . A special filter is electronically activated by a switch in the  endoscope  leading to the use of ambient light of wavelengths of 415 nm (blue) and 540 nm (green). [ 1 ] [ 2 ]  Because the peak light absorption of hemoglobin occurs at these wavelengths, blood vessels will appear very dark, allowing for their improved visibility and in the improved identification of other surface structures. [ 3 ]


In  gastrointestinal  endoscopy, narrow-band imaging has found use in the identification of  Barrett's esophagus , [ 3 ]  in the identification of pit patterns to classify colorectal  polyps  and  tumours , [ 4 ]  and in the identification of atypical  dysplastic  cells in the colon of patients with  ulcerative colitis . [ 5 ]  Also, in  cystoscopy , which is the examination of the  urinary bladder  with an  endoscope , narrow-band imaging is useful in differentiating between benign and malignant cells. [ 6 ]


Alternative methods to improve visualization of the mucosa in endoscopy include  chromoendoscopy ,  confocal microscopy  and  optical coherence tomography . [ citation needed ]


The  non-lifting sign  is a finding on  endoscopic  examination that provides information on the suitability of large flat or sessile colorectal polyps for  polypectomy  by  endoscopic mucosal resection  (EMR). When fluid is injected under a polyp in preparation for endoscopic mucosal resection, some polyps do not "lift", indicating that the polyp is not separating from the  submucosa . This makes polypectomy more technically difficult, and increases the risk of  intestinal perforation  if polypectomy is then attempted. It is also thought to be indicative of an early colorectal cancer that has invaded the submucosa significantly (sm3 – invasion down to the lower one-third of the submucosa), which would make surgical removal of the tumour preferable to allow complete removal of the cancer. Consequently, the non-lifting sign is generally considered to be a  contraindication  to performing endoscopic mucosal resection. [ 1 ]


The non-lifting sign was first described in 1994 by Yoshiharu Uno and Akihiro Munakata of the Hirosaki University School of Medicine, Japan. [ 2 ]


In 1999 the same team showed that the presence of a non-lifting sign correlated with the depth of invasion of the submucosa by early colorectal cancers that were being considered for endoscopic resection. [ 3 ]  The tumours which did lift when fluid was injected were found to be less invasive than those that did not (sm1 or sm2 - invasion confined to the upper two-thirds of the submucosa, with at least 1mm of uninvolved submucosa underneath). It is thought that the non-lifting sign is due to fibrosis around the tumour causing tethering of the tumour to the  muscularis mucosae .


Subsequent research suggested that the non-lifting sign is less accurate in determining depth of tumour invasion than the assessment of tumours by the endoscopist, but still suggests that the presence of the sign makes endoscopic resection technically difficult. [ 4 ]  However, more recently it has been found that fibrosis may be caused when a tumour is biopsied before endoscopic mucosal resection is attempted, which leads to a false positive non-lifting sign and therefore reduces the apparent accuracy of the sign. [ 1 ]  The authors, therefore, recommended avoidance of biopsy of the lesions if EMR is to be attempted, and if biopsies have been taken the time before EMR is attempted should be minimised.


The Ottawa Bowel Preparation Scale  is used to assess a patient's bowel preparation for  colonoscopies . [ 1 ]


The scale assesses three components of the large intestine: (1) the  rectosigmoid colon , (2) the mid colon and (3) the right colon. A maximum score of 4 is used for each section of the  large intestine . A score of 0 is given if the bowel preparation is excellent, meaning the mucosal detail is visible, there is no fluid and almost no stool. A score of 1 is given if the bowel preparation is good, meaning there is turbid fluid/stool but the  mucosa  is visible and wash/suction is not needed. A score of 2 is given if the bowel preparation is fair, meaning there is fluid/stool obscuring the mucosa, suction is needed but wash is not needed. A score of 3 is given if the bowel preparation is poor, meaning that stool obscures the mucosa and suctioning/washing only provides an OK mucosa view. A score of 4 is given if the bowel preparation is inadequate, meaning that stool obscures the mucosa despite major washing/suctioning. The total score is calculated by adding up all 3 scores. The scale has a range from 0 (perfect) to 14 (solid stool in each section and lots of fluid, i.e., a completely unprepared colon). [ 2 ]


Other validated preparation scales are the Aronchick Scale and the Boston Bowel Preparation Scale. [ 3 ]


In medicine, the  poppy seed test  is a  diagnostic test  used before surgery to predict if surgery will find a  vesicointestinal fistula  or  colovesical fistula  (an abnormal direct pathway between the  colon  and  urinary bladder ) or other type of  vesicointestinal fistula .


The test is very simple. The patient is fed 1.25 ounces of  poppy seeds  with 12 ounces of fluid or 6 ounces of yogurt. The patient's  urine  is then collected for the next 48 hours and examined for poppy seeds. If a poppy seed is found in the urine, the patient has a colovesical or related fistula. [ 1 ]


The test is very accurate.  In a series of 49 patients who underwent surgery for colovesical fistula due to  sigmoid diverticulitis , the poppy seed test gave a correct diagnosis more often than abdominopelvic computerized tomography, magnetic resonance tomography of the abdomen, cystogram, retrograde colonic enema, urethrocystoscopy, and colonoscopy. [ 2 ]   In a series of 20 patients in the  United States , the poppy seed test was significantly more accurate than  computed tomography . [ 3 ]   In these two series, respectively,  sensitivity  of the test was 94.6% and 100%.  Because of the physical nature of the test,   specificity  of the test is necessarily 100%. [ citation needed ]


The test is very inexpensive.  In the United States it has been reported to cost under 6 dollars and two  orders of magnitude  less than computed tomography. [ 3 ]


The test was first described in the  English  medical literature in 2001, by a group of  urologists  in  Germany .  From 1994 to 1999, they gave 250 grams (8.8 oz) of poppy seeds to a series of 17 patients, then examined the patients' urine for two days.  The test results were correct for all patients:  11 patients with fistulas did pass poppy seeds in their urine and 6 patients without fistulas did not pass poppy seeds. [ 4 ]


Pouchoscopy  is a minimally invasive  endoscopic  procedure to examine an  ileo-anal pouch , a replacement for the  colon  /  rectum  which is surgically created from the  small intestine  (ileum) as treatment for  ulcerative colitis , a preventive measure in certain genetic illnesses such as  FAP  or  HNPCC  or as a procedure in the treatment of  colon cancer . Typically, a  fiber optic camera  on a flexible tube is passed through the  anus . Pouchoscopy is the first line test to evaluate pouch dysfunction, and is used for surveillance in individuals with genetic cancer syndromes (FAP). [ 1 ]  While pouchoscopy may help assess the integrity of the  J-pouch  (hence the name pouchoscopy), this evaluation is more commonly completed using a pouchogram (a necessary step in preparing for reversal of the temporary  ileostomy , or takedown surgery). A pouchoscopy is normally part of a routine follow up and is used to confirm the diagnosis of  pouchitis  and  cuffitis . [ citation needed ]


The  Ranson criteria  form a  clinical prediction rule  for predicting the prognosis and mortality risk of  acute pancreatitis . They were introduced in 1974 by the  English - American   pancreatic  expert and  surgeon  Dr. John Ranson (1938–1995). [ 1 ]


A score of 3 or more indicates severe acute pancreatitis. This can cause  organ failure ,  necrosis , infected necrosis,  pseudocyst , and  abscess . If diagnosed with severe acute pancreatitis, people will need to be admitted to a  high-dependency unit  or  intensive care unit .


At admission:


Within 48 hours:


Alternatively, pancreatitis severity can be assessed by any of the following: [ 2 ]


Or


Digital rectal examination  (DRE), also known as a  prostate exam  ( Latin :  palpatio per anum (PPA) ,  lit.   'palpation through the anus'), is an internal examination of the  rectum  performed by a  healthcare provider .


Prior to a 2018 report from the  United States Preventive Services Task Force , a digital exam was a common component of  annual exams  for older men, as it was thought to be a reliable  screening test  for  prostate cancer . [ 1 ] [ 2 ]


This examination may be used:


The digital rectal examination is a relatively simple medical procedure. The patient undresses and is then placed in a position where the  anus  is accessible (lying on the side,  squatting  on the examination table, bent over it, or lying down with feet in stirrups). If the patient is lying on their side, the physician will usually have them bring one or both legs up to their chest. If the patient bends over the examination table or the back of a chair, the physician will have them place their elbows on the table and squat down slightly. If the patient uses the supine position, the physician will ask the patient to slide down to the end of the examination table until their buttocks are positioned just beyond the end and then place their feet in the stirrups. The physician spreads the buttocks apart and will usually examine the external area (anus and perineum) for any abnormalities such as  hemorrhoids , lumps, or rashes. Then, as the patient relaxes and bears down (as if having a bowel movement), the physician slips a lubricated finger into the rectum through the anus and palpates the insides for a short time. [ medical citation needed ]


Due to the taboos surrounding the anus and the potential for discomfort and embarrassment, the rectal exam is a common  comedic device , including in episodes of  Saturday Night Live , [ 30 ]   Impractical Jokers ,  Futurama ,  Family Guy ,  South Park ,  Letterkenny , and the movie  Fletch , with  M. Emmet Walsh  as the general practitioner and  Chevy Chase  as the patient being examined. Similar activities to the rectal exam are attributed to extraterrestrials in video games such as  Saints Row IV ,  Gaia Online  and  Destroy All Humans! . [ 31 ]  The practice of rectal exams without prior consent by medical students has been an area of concern. [ 32 ]  In 2024, the US  Department of Health and Human Services  banned  rectal examination (and pelvic and breast exams) without written informed consent, when such exams are done by medical students, nurse practitioners, or physician assistants for  “educational and training purposes”. [ 33 ]


In  veterinary medicine  rectal examination is useful in  dogs  for analysis of the  prostate  (as in men), pelvic  urethra , sublumbar  lymph nodes , and  anal glands . In  horses  it is a vital component of the clinical examination for  colic , to determine the presence or absence of bowel torsion,  impaction , or displacement. When horses undergo a rectal examination there is a small risk of a  rectal  tear occurring, which can be a life-threatening event, rapidly leading to  peritonitis  and  septic shock . It is also a common procedure in cattle, and is one method of diagnosing pregnancy in both the horse and the cow. [ citation needed ]


The procedure in dogs and cats is similar to humans. For the horse, the patient stands in a  stock  and may be sedated. The examiner puts on a  long glove  that extends to the shoulder. The examiner inserts the hand and arm into the rectum as far as necessary. [ citation needed ]


Reynolds' pentad  is a collection of signs and symptoms consistent with obstructive  ascending cholangitis , a serious infection of the  biliary tract . It is a combination of  Charcot's triad  ( right upper quadrant  pain,  jaundice , and  fever ) with  shock  ( low blood pressure ,  tachycardia ) and an  altered mental status . [ 1 ]  Sometimes the two additional signs are listed simply as  low blood pressure  and  confusion . [ 2 ]


It was named after surgeon  Benedict Reynolds , who described it (along with Everett Dargan) in 1959. [ 1 ]


Rockall risk scoring system   attempts to identify patients at risk of adverse outcome following acute  upper gastrointestinal bleeding . Rockall  et al.  identified independent risk factors [ 1 ]  in 1996 which were later shown to predict mortality accurately. The scoring system uses clinical criteria (increasing age, co-morbidity, shock) as well as endoscopic finding (diagnosis, stigmata of acute bleeding). It is named for Professor Tim Rockall, who was the main investigator and first author of the studies that led to its formulation. A convenient mnemonic is ABCDE - i.e. Age, Blood pressure fall (shock), Co-morbidity, Diagnosis and Evidence of bleeding. [ citation needed ]


Total score is calculated by simple addition. A score less than 3 carries good prognosis but total score more than 8 carries high risk of mortality. [ 3 ]


The  Schilling test  was a medical investigation used for patients with  vitamin B 12  (cobalamin) deficiency. [ 1 ]  The purpose of the test was to determine how well a patient is able to absorb B12 from their intestinal tract.  The test is now considered obsolete and is rarely performed, and is no longer available at many medical centers.  It is named for  Robert F. Schilling . [ 2 ]


The Schilling test has multiple stages. [ 3 ]  As noted below, it can be done at any time after vitamin B 12  supplementation and body store replacement, and some clinicians recommend that in severe deficiency cases, at least several weeks of vitamin repletion be done before the test (more than one B 12  shot, and also oral folic acid), in order to ensure that impaired absorption of B 12  (with or without intrinsic factor) is not occurring due to damage to the intestinal mucosa from the B 12  and folate deficiency themselves.


In the first part of the test, the patient is given  radiolabeled  vitamin B 12  to drink or eat. The most commonly used radiolabels are  57 Co and  58 Co . An  intramuscular  injection of unlabeled vitamin B 12  is given an hour later. This is not enough to replete [ clarification needed ]  or saturate body stores of B 12 . The purpose of the single injection is to temporarily saturate B 12  receptors in the liver with enough normal vitamin B 12  to prevent radioactive vitamin B 12  binding in body tissues (especially in the liver), so that if absorbed from the G.I. tract, it will pass into the urine. The patient's urine is then collected over the next 24 hours to assess the absorption.


Normally, the ingested radiolabeled vitamin B 12  will be absorbed into the body. Since the body already has liver receptors for  transcobalamin /vitamin B 12  saturated by the injection, much of the ingested vitamin B 12  will be  excreted  in the urine.


The normal test will result in a higher amount of the radiolabeled cobalamin in the urine because it would have been absorbed by the intestinal epithelium, but passed into the urine because all hepatic B12 receptors were occupied. An abnormal result is caused by less of the labeled cobalamin to appear in the urine because it will remain in the intestine and be passed into the feces.


If an abnormality is found, i.e. the B12 in the urine is only present in low levels, the test is repeated, this time with additional oral  intrinsic factor .


This stage is useful for identifying patients with  bacterial overgrowth syndrome . The physician will provide a course of 2 weeks of antibiotics to eliminate any possible bacterial overgrowth and repeat the test to check whether radio-labeled Vitamin B12 would be found in urine or not.


This stage, in which  pancreatic enzymes  are administered, can be useful in identifying patients with  pancreatic insufficiency . The physician will give 3 days of pancreatic enzymes followed by repeating the test to check if radio-labeled Vitamin B12 would be detected in urine.


In some versions of the Schilling test, B 12  can be given both with and without intrinsic factor at the same time, using different cobalt radioisotopes  57 Co and  58 Co, which have different radiation signatures, in order to differentiate the two forms of B 12 . This is performed with the 'Dicopac' kitset. This allows for only a single radioactive urine collection. [ 4 ]


Note that the B 12  shot which begins the Schilling test is enough to go a considerable way toward treating B 12  deficiency, so the test is also a partial  treatment  for B 12  deficiency. Also, the classic Schilling test can be performed at any time, even after full B 12  repletion and correction of the anemia, and it will still show if the cause of the B 12  deficiency was intrinsic-factor related. In fact, some clinicians have suggested that folate and B 12  replacement for several weeks be normally performed  before  a Schilling test is done, since folate and B 12  deficiencies are both known to interfere with intestinal cell function, and thus cause malabsorption of B 12  on their own, even if intrinsic factor is being made. This state would then tend to cause a false-positive test for both simple B 12  and intrinsic factor-related B 12  malabsorption. Several weeks of vitamin replacement are necessary, before epithelial damage to the G.I. tract from B 12  deficiency is corrected.


Many labs have stopped performing the Schilling test, [ 5 ]  due to lack of production of the cobalt radioisotopes and labeled-B 12  test substances. Also, injection replacement of B 12  has become relatively inexpensive, and can be self-administered by patients, as well as megadose oral B 12 . Since these are the same treatments which would be administered for most causes of B 12  malabsorption even if the exact cause were identified, the diagnostic test may be omitted without damage to the patient (so long as follow-up treatment and occasional serum B 12  testing is not allowed to lapse).


It is possible for use of other radiopharmaceuticals to interfere with interpretation of the test. [ 6 ]


Sigmoidoscopy  ("sigma", the Greek term for letter " s/ς " + "eidos" + "scopy": namely, to look inside an "s"/"ς"-like object) is the  minimally invasive   medical  examination of the large  intestine  from the  rectum  through to the nearest part of the  colon , the  sigmoid colon . There are two types of sigmoidoscopy:  flexible sigmoidoscopy , which uses a flexible  endoscope , and  rigid sigmoidoscopy , which uses a rigid device. Flexible sigmoidoscopy is generally the preferred procedure. A sigmoidoscopy is similar to, but not the same as, a  colonoscopy . A sigmoidoscopy only examines up to the  sigmoid , the most distal part of the colon, while colonoscopy examines the whole large bowel.


Flexible sigmoidoscopy enables the  physician  to look at the inside of the large intestine from the rectum to the left side of the colon, called the sigmoid. Physicians may use the procedure to find the cause of  diarrhea ,  abdominal pain , or  constipation . They also use it to look for benign and malignant  polyps , as well as early signs of  cancer  in the descending colon and rectum. [ 1 ]  With flexible sigmoidoscopy, the physician can see  intestinal bleeding ,  inflammation , abnormal growths, and  ulcers  in the descending colon and rectum. Flexible sigmoidoscopy is not sufficient to detect polyps or cancer in the ascending or transverse colon (two-thirds of the colon). However, although in absolute terms only a relatively small section of the large intestine can be examined using sigmoidoscopy, the sites which can be observed represent areas which are most frequently affected by diseases such as  colorectal cancer , for example the  rectum .


For the procedure, the patient must lie on their side on the examining table. The physician inserts a short, flexible, lit tube into the rectum and slowly guides it into the colon. The tube is called a sigmoidoscope. The scope transmits an image of the inside of the rectum and colon, so the physician can carefully examine the lining of these organs. The scope also blows air into these organs, which inflates them in order to help the physician see better.


If anything unusual is in the rectum or colon, like a polyp or inflamed tissue, the physician can remove a piece of it using instruments inserted into the scope. The physician will send that piece of tissue ( biopsy ) to the lab for testing.


Bleeding and puncture of the colon are possible complications of sigmoidoscopy. However, such complications are uncommon.


Flexible sigmoidoscopy takes 10 to 20 minutes. During the procedure, the patient might feel pressure and slight cramping in the lower abdomen, but the patient will feel better afterward when the air leaves the colon.


The colon and rectum must be completely empty for flexible sigmoidoscopy to be thorough and safe, thus the patient must drink only clear liquids for 12 to 24 hours beforehand. This includes bouillon or  broth ,  gelatin , strained fruit  juice , water, plain  coffee , plain  tea , or diet  soft drinks .


The night before or right before the procedure, the patient receives a  laxative  (e.g.  macrogol ,  lactulose  etc.) and/or an  enema , which is a liquid solution that washes out the intestines.
No sedation is required during this procedure as long as the examination does not exceed the level of the  splenic flexure .


Rigid sigmoidoscopy may be useful in ano-rectal diseases such as bleeding per rectum or inflammatory rectal disease, particularly in the general practice and pediatrics.


For performing the examination, the patient must lie on the left side, in the so-called  Sims' position . The bowels are previously emptied with a  suppository , and a  digital rectal examination  is first performed. The sigmoidoscope is lubricated and inserted with  obturator  in general direction of the  navel . The direction is then changed and the obturator is removed so that the physician may penetrate further with direct vision. A  bellows  is used to insufflate air to distend the rectum. Lateral movements of the sigmoidoscope's tip negotiate the  Houston valve  and the  recto-sigmoid junction .


Several studies have shown the potential benefits of sigmoidoscopy in detecting colorectal cancer.


In a 2009 Norwegian study, results were somewhat inconclusive at seven years. [ 2 ]


We found a trend towards reduced mortality from colorectal cancer for both total colorectal cancer mortality (27% reduction) and rectosigmoidal cancer mortality (37%), but this was not statistically significant in intention to screen analysis. Corresponding reductions in mortality among attenders (that is, the people actually screened, instead of just the ones in the group to be screened—this data set may include selection bias) were 59% and 76%, both statistically significant compared with the control group[.] [ 2 ]


The study saw no detectable difference in all-cause mortality.


A 2010 British study [ 3 ]  showed sigmoidoscopy reduced "overall colorectal cancer incidence and mortality by 31 percent", and "incidence of cancer in just the lower part of the colon (or distal colon) was reduced by approximately 50 percent for those who underwent screening compared with those in the control group." [ 4 ]
Overall colon-cancer mortality was reduced by 43% (thus preventing one cancer per 200 screenings, and one cancer death per 500 screenings).  The study also showed that the effect was persistent—a single sigmoidoscopy reduced cancer rates for the length of the 11-year study.


Although generally considered quite safe, sigmoidoscopy does carry the very rare possibility of tearing of the intestinal wall by the instrument, which could require immediate surgery to repair the tear; in addition, removal of a polyp may sometimes lead to localized bleeding which is resistant to cauterization by the instrument and must be stopped by surgical intervention. [ 5 ]


The  Sims position , or left lateral Sims position, named after the gynaecologist  J. Marion Sims , is usually used for  rectal examination , treatments,  enemas , and examining patients for  vaginal wall prolapse . [ 1 ] [ 2 ]


The Sims Position is described as in the person lying on the left side, left hip and lower extremity straight, and right hip and knee bent. It is also called lateral recumbent position. [ 3 ]  Sims' position is also described as the person lying on the left side with both legs bent. [ 4 ]


The position is described as follows:


Common uses:


Steatocrit  or acid steatocrit is a simple, rapid  gravimetric  method to determine  steatorrhea . The test is simple, rapid, inexpensive, and reliable. It is a  qualitative test that can be used when other methods are impractical.


An elevated steatocrit is indicative of fat malabsorption resulting in  steatorrhea . This generally results from pancreatic exocrine insufficiency but can also occur with severe small bowel disease i.e.  celiac disease , liver diseases such as  Primary Biliary Cirrhosis  or medications that inhibit fat absorption such as  orlistat .


The  stool guaiac test  or  guaiac fecal occult blood test  ( gFOBT ) is one of several methods that detects the presence of  fecal occult blood [ 1 ]  ( blood  invisible in the  feces ). [ 2 ]  The test involves placing a fecal sample on  guaiac  paper (containing a phenolic compound, alpha-guaiaconic acid, extracted from the wood  resin  of  Guaiacum  trees) and applying hydrogen peroxide which, in the presence of blood, yields a blue reaction product within seconds.


The American College of Gastroenterology has recommended the abandoning of gFOBT testing as a colorectal cancer screening tool, in favor of the fecal immunochemical test (FIT). [ 3 ]   Though the FIT is preferred, even the guaiac FOB testing of average risk populations may have been sufficient to reduce the mortality associated with  colon cancer  by about 25%. [ 4 ]   With this lower efficacy, it was not always cost effective to screen a large population with gFOBT. [ 5 ] [ 6 ] [ 7 ] [ 8 ]


The stool guaiac test involves fasting from iron supplements, red meat (the blood it contains can turn the test positive), certain vegetables (which contain a chemical with peroxidase properties that can turn the test positive), and vitamin C and citrus fruits (which can turn the test falsely negative) for a period of time before the test. It has been suggested that cucumber, cauliflower and horseradish, and often other vegetables, should be avoided for three days before the test. [ 9 ]


In testing,  feces  are applied to a thick piece of paper attached to a thin film coated with guaiac.  Either the patient or medical professional smears a small fecal sample on to the film.  The fecal sample is obtained by catching the stool and transferring a sample with an applicator.  Digital rectal examination specimens are also used but this method is discouraged for colorectal cancer screening due to very poor performance characteristics. [ 10 ]


Both sides of the test card can be peeled open, to access the inner guaiac paper.  One side of the card is marked for application of the stool and the other is for the developer fluid. [ citation needed ]


After applying the feces, one or two drops of  hydrogen peroxide  are then dripped on to the other side of the film, and it is observed for a rapid blue color change. [ citation needed ]