Gastrointestinal and Nutrition
What you must know
Organize GI around location and acuity. Esophagus: GERD is clinical; alarm features (dysphagia, odynophagia, weight loss, anemia, vomiting, age over 60 with new symptoms) trigger endoscopy. Stomach: peptic ulcer disease is usually NSAID- or H. pylori-related; test for H. pylori and treat, confirming eradication when indicated. Small bowel: celiac disease is screened with tissue transglutaminase IgA plus a total IgA (IgA deficiency causes false negatives), and testing is meaningless on a gluten-free diet. Colon: ulcerative colitis is continuous from the rectum; Crohn disease is transmural with skip lesions, fistulas, and perianal involvement.
Liver and pancreas: know hepatitis serologies well enough to distinguish acute, chronic, resolved, and vaccinated patterns. Cirrhosis complications drive questions - ascites, spontaneous bacterial peritonitis (ascitic neutrophils 250 or more), variceal bleeding, hepatic encephalopathy (lactulose, rifaximin), and HCC surveillance with ultrasound plus AFP every six months. Acute pancreatitis: two of three criteria (typical pain, lipase over three times normal, imaging), early balanced fluid resuscitation, and early oral feeding rather than prolonged nothing-by-mouth. Nutrition: BMI and unintentional weight loss are better markers than albumin, which reflects inflammation. Watch for refeeding syndrome in severely malnourished patients - replete thiamine, phosphorus, magnesium, and potassium before aggressive calories.
Traps
- Labeling dyspepsia as GERD without triaging alarm features.
- Ordering celiac serology in a patient already avoiding gluten.
- Assuming a normal lipase excludes pancreatitis.
- Using albumin as a nutritional marker.
Rule of thumb
Right upper quadrant pain plus fever plus jaundice (Charcot triad) means ascending cholangitis - antibiotics and urgent biliary drainage, not outpatient imaging.