What’s it all about?Gastroenterology is a subspecialty of internal medicine. It deals with conditions and diseases ofthe organs of the digestive tract and associated solid organs such as the pancreas, liver, andgallbladder. The most frequent complaints seen in the clinic and the hospital include abdominalpain, nausea, vomiting, diarrhea and GI bleeding.Management of gastrointestinal problems can be both medical and surgical. A key aspect of GI islearning to differentiate benign processes from those that are more serious and possibly needinga procedure or surgical intervention.Conditions you may be asked about in the first weekThe conditions you will usually be asked about in your first week are the more commoncomplaints and diagnoses. The most important things you will be asked involve differentialdiagnoses, and how to work up the problem. The most common problems in gastroenterologyinclude: • abdominal pain, • differentiating and working up a GI bleed, • diarrhea, and • gastroesophageal reflux disease.You may also come across other common conditions as you progress, such as: peptic ulcerdisease, appendicitis, diverticulitis, colon cancer, hepatitis, cirrhosis, cholecystitis, pancreatitis,irritable bowel syndrome and inflammatory bowel syndrome.Abdominal painPQRST • Presentation: ‘How?’ and ‘Where?’ • Quality: ‘Is the pain sharp, dull, burning, colicky?’ • Radiation: ‘Does the pain radiate anywhere (e.g. groin, back, shoulder)?’ • Severity: ‘How bad is the pain on a scale of 1 to 10?’, ‘What makes it better or worse?’ • Timing: ‘When does it occur?’, ‘How long?’, ‘Associations?’The chronological sequence of events in the patients history is often more important thanemphasis on the location of pain.Careful attention should be paid to the extra-abdominal regions that may be responsible forabdominal pain. An accurate menstrual history in a female patient is essential.Abdominal examinations are mandatory in every patient with abdominal pain.Pelvic and rectal examinations are recommended in patients with lower abdominal painespecially if the pain is acute.Differential diagnosisSome causes of abdominal pain are obvious, some less so. It’s best to associate pain withquadrants. The following guidelines are meant to be general, because all disorders have beenknown to present atypically. • Right upper quadrant: Biliary colic, cholangitis, cholecystitis, pyelonephritis, renal colic, renal infarct, pneumonia, hepatic abscess, hepatitis, retrocecal appendicitis, pelvic inflammatory disease (PID).
• Left upper quadrant: Splenic infarct, pancreatitis, pyelonephritis, renal colic, renal infarct, pneumonia, PID. • Epigastric: Gastritis, gastric ulcer, duodenal ulcer, pancreatitis, carcinoma, pancreatic cancer, reflux esophagitis (sub-sternal pain). • Right lower quadrant: Appendicitis, ovarian cyst/torsion, ectopic pregnancy, salpingitis, urinary tract infection (UTI), renal colic, Crohn’s disease, colitis, cancer, PID. • Left lower quadrant: Diverticulitis, colitis, sigmoid volvulus, ovarian cyst/torsion, ectopic pregnancy, renal colic, UTI, PID. • Suprapubic: Appendicitis, diverticulitis, salpingitis, uterine fibroid, ovarian cyst, cystitis, PID.GI bleedThe first step in working up a GI bleed is to assess your patient’s age: • patients under the age of 60 have a mortality of <1%; • patients over 80 have a mortality of >20%Check also for shock, renal disease, liver disease and cardiovascular disease (includinghypertension) – these all increase the chances that your patient may die.Check your patient’s vital signs and make sure they are stable. Initial resuscitation requiresrestoration of intravascular volume, correction of coagulopathy and airway protection.Once it has been determined that the patient is stable, initial work-up includes nasogastric (NG)aspiration, rectal exam and Hemoccult, endoscopy and colonoscopy, barium studies, radionuclideimaging (this can detect a bleeding rate as low as 0.1 mL/min, but is only positive about 45% ofthe time) and angiography (a bleed must exceed 0.5 mL/min to be detected). Weigh up thesignificant pros and cons of each of the above.Upper GI bleeding • Hematemesis, melena > hematochezia, tachycardia, hypotension. • Evaluation: endoscopy if stable (this is urgent in patients with an active bleed and/or liver disease), NG tube and NG lavage. • Common causes: peptic ulcer disease, gastritis, esophageal varices, vascular abnormalities, Mallory-Weiss tear, neoplasm, esophagitis, stress ulcer. • Initial management: protect airway, stabilize with IV fluids, blood products. • Further management: endoscopy followed by therapy directed at underlying cause.Lower GI bleeding • Hematochezia > melena, but can be either. • Rule out upper GI bleed with NG tube and NG lavage, colonoscopy if stable. • Common causes: diverticulosis, arteriovenous malformations, colon cancer, inflammatory bowel disease, anorectal disease, mesenteric ischemia. • Initial management: stabilize patient with IV fluids, blood products if necessary. • Further management: rule out upper GI bleed; colonoscopy and management directed at underlying cause (eg. surgical resection of cancer, diverticula).
DiarrheaHx should include duration, frequency, estimated volume and consistency of each bowelmovement, relation to meals, associated fever, pain, nausea, vomiting, blood in stool, history oftravel, medication use.Major types of diarrhea are secretory, osmotic, exudative. • Secretory: Enterotoxins (Cholera, E. coli, S. aureus), gastric hypersecretion, laxative abuse. • Osmotic: Malabsorption. • Exudative: Shigella, Salmonella, C. difficile.Infection is the most common cause of diarrhea, and is usually caused by food poisoning.Initial workup includes CBC with differential, chemistry panel with BUN and creatinine. WBCs instool indicate CHESS organisms: • Campylobacter. • Hemorrhagic E. coli. • Entamoeba histolytica. • Salmonella. • Shigella.Treatment consists of correction of fluid and electrolyte abnormalities and reduction of symptoms.Avoid antibiotics in enteric salmonella infection because a prolonged carrier state may beinduced. Antimotility agents should be used cautiously with inflammatory diarrhea.Gastroesophageal reflux diseaseGastroesophageal reflux disease is symptomatic reflux of gastric contents into the esophagus. Itis one of the most common conditions you will see . Symptoms include heartburn, chest pain,regurgitation, belching, dysphagia, and halitosis. Additional pulmonary symptoms includingchronic cough, hoarseness, wheezing and asthma. If you see a patient who complains of chronictickle in the back of the throat with associated cough, consider gastroesophageal reflux diseaseafter ruling out other possibilities. Ask your patient whether pain wakes them up at night—thisgenerally is NOT reflux and more likely associated with ulcer disease.Risk factors include smoking, drinking alcohol, eating chocolate or mints, hiatal hernia, obesity,increased intra-abdominal pressure, and increased plasma progesterone levels.Diagnosis is usually based on history. • Barium swallow: least sensitive test. • 24hr pH monitoring: gold-standard for measuring GERD (pH <4). • Manometry: may detect transient lower esophageal sphincter (LES) relaxation, hiatal hernia. • Esophagogastroduodenoscopy (EGD) with biopsies, if patient has long-standing symptoms – to rule out Barrett’s esophagus and adenocarcinoma. • Acid-perfusion test (Bernstein test) can be done but is becoming less common.
Treatment includes lifestyle changes, drug management and surgery. • Lifestyle: weight loss, elevate head of bed, avoid certain foods. • Drugs: antacids, H2-receptor antagonists or proton pump inhibitors (PPIs). • Surgery: nissen fundoplication if refractory or severe disease.Complications include ulceration, strictures, upper GI bleeding, aspiration and risk of pneumonia,Barrett’s esophagus (which may lead to adenocarcinoma of the esophagus).Do’s and Don’ts • ALWAYS remember to ask women about their menstrual cycle and sexual activity since many gynecological and obstetrical conditions can mimic GI complaints. • Do perform a rectal exam in association with Hemoccult. No-one likes having a rectal exam, but it is almost always pertinent, especially when ruling out GI bleeding.History and physical examinationAsk about bowel habits and any changes in them, flatus, nausea, vomiting, dark or tarry stools,and association of symptoms with eating or types of food. Ask the patient to point to the locationof the pain before initiating the exam. • Inspect the abdomen, particularly noting the contour, any scars and locations, and noticeable masses or bulges. • Listen for bowel sounds as well as abdominal aortic and renal bruits. • Percuss the abdomen; tympanic abdomen suggests obstruction. • Always start palpation away from areas of pain. • Do light palpation followed by deeper palpation; note any masses or muscle rigidity (“guarding”).Percussion is also a good way to test for “rebound” tenderness or acute abdomen. Somephysicians may try to bump the bed or exam table to assess for peritoneal inflammation, as wellas asking their patient to cough or just percuss the abdomen; these will usually elicit “rebound” aswell. BUT always consider your patient’s comfort – testing for rebound causes additional pain andyou should make sure that it is absolutely necessary.AuthorBy Matthew Reinersman, Southern Illinois University School of Medicine.