Gastroenterology
11 high-yield topics. Open a topic to review its pearls.
Dysphagia
Oropharyngeal vs esophageal
Key Points
- Oropharyngeal: neuromuscular (stroke, myasthenia, ALS)
- Esophageal: mechanical (stricture, ring, cancer) vs motility (achalasia, spasm)
- Solids only progressing: mechanical obstruction
- Solids and liquids from start: motility disorder
- Achalasia: birds beak on barium, LES fails to relax
GERD
Pathophysiology and treatment
Pathophysiology
- LES incompetence, impaired esophageal clearance
- Delayed gastric emptying, increased intra-gastric pressure
Management
- Lifestyle: weight loss, elevate head of bed
- PPI: gold standard
- Surgery: Nissen fundoplication
Complications
- Erosive esophagitis, Barrett esophagus
- Strictures, esophageal adenocarcinoma risk
Peptic Ulcer Disease
H. pylori and NSAID
H. pylori
- Diagnosis: urea breath test, stool antigen, serology
- Triple therapy: PPI + amoxicillin + clarithromycin
- Bismuth quadruple: PPI + bismuth + metronidazole + tetracycline
- Retest at 4+ weeks post-treatment
NSAID-Related
- Risk: age >65, prior GI bleed, concurrent steroids
- PPI prophylaxis for high-risk patients on chronic NSAIDs
GI Bleeding
Upper and lower
Upper GI Bleed
- Causes: PUD, varices, Mallory-Weiss, gastritis
- Melena or hematemesis
- BUN:Cr ratio elevated
- Endoscopy for diagnosis and treatment
Dyspepsia & Dumping
- Dyspepsia: consider H. pylori, cardiac if risk factors
- Dumping syndrome: post gastric bypass, early (osmotic) vs late (hypoglycemia)
Diarrhea
Acute and chronic
Classification
- Osmotic: stops with fasting (lactose intolerance)
- Secretory: continues with fasting (VIPoma, carcinoid)
- Inflammatory: blood, WBCs (IBD, invasive infection)
- Malabsorptive: fat (steatorrhea, celiac)
Infectious
- C. difficile: antibiotics, toxin assay → oral vancomycin/fidaxomicin
- Traveler diarrhea: E. coli, fluoroquinolones
- Giardia: camping, metronidazole
Irritable Bowel Syndrome
Diagnosis and management
Key Points
- Rome criteria: recurrent abdominal pain with defecation
- No alarm features (weight loss, bleeding, anemia, nocturnal symptoms)
- Diagnosis of exclusion
- Treatment: dietary changes, antispasmodics, fiber
Inflammatory Bowel Disease
Crohn and UC
Crohn Disease
- Any part of GI tract, skip lesions
- Transmural inflammation → fistulas, abscesses, strictures
- Cobblestone appearance
- Increased oxalate stones
Ulcerative Colitis
- Continuous inflammation, colon only
- Mucosal/submucosal, crypt abscesses
- Complications: toxic megacolon, colon cancer risk
- Colonoscopy surveillance after 8 years
Hepatitis
Viral hepatitis A-E
Serology
- Hep A: fecal-oral, self-limited, IgM anti-HAV acute
- Hep B: HBsAg (infection), anti-HBs (immunity), HBeAg (infectivity)
- Hep C: chronic, cirrhosis/HCC risk, treat with direct-acting antivirals
- Hep E: pregnant travelers, high mortality
Chronic Hepatitis
- Hep B and C most common causes
- Monitor for cirrhosis and hepatocellular carcinoma
Cirrhosis
Complications and MELD
Complications
- Ascites: SAAG >1.1 = portal HTN; treat with diuretics, paracentesis
- SBP: PMN >250, treat with cefotaxime; prophylaxis with fluoroquinolone
- Hepatic encephalopathy: lactulose, rifaximin
- Varices: beta blockers, banding
- Hepatorenal syndrome: does not respond to volume, needs transplant
Liver Disease in Pregnancy
- Intrahepatic cholestasis: 3rd trimester, pruritus → cholestyramine
- Acute fatty liver: RUQ pain, elevated bilirubin → deliver baby
- Most common abnormal LFTs in pregnancy: viral hepatitis then gallstones
Pancreatitis
Acute and chronic
Acute Pancreatitis
- Causes: gallstones, alcohol most common
- Elevated lipase/amylase
- Ranson criteria for severity
- Treatment: IV fluids, pain control, NPO
Chronic Pancreatitis
- Calcifications, steatorrhea, DM
- Pancreatic enzyme replacement
Ischemic Bowel Disease
Acute and chronic
Key Points
- Acute mesenteric ischemia: Afib, pain out of proportion to exam → angiogram
- Chronic: post-prandial pain, weight loss, food fear
- Ischemic colitis: watershed areas (splenic flexure)