Gastroenterology and Hepatology
GI bleeding
Upper GI bleeding with cirrhosis requires vasoactive therapy (octreotide) plus prophylactic ceftriaxone and pre-endoscopic PPI. Use restrictive transfusion thresholds (about 7 g/dL; 8 g/dL with cardiovascular disease).
Ascites and cirrhosis
Always send ascitic fluid for cell count and albumin with a paired serum albumin. A serum-ascites albumin gradient ≥1.1 g/dL indicates portal hypertension; below that consider tuberculosis, malignancy, or pancreatic ascites. Spontaneous bacterial peritonitis is diagnosed at ≥250 polymorphonuclear cells/mm³ - treat and start secondary prophylaxis. Screen for varices, offer lactulose and rifaximin for hepatic encephalopathy, and avoid NSAIDs, aminoglycosides, and benzodiazepines.
Liver enzymes
Hepatocellular patterns (AST/ALT predominant) suggest viral, drug, alcohol, autoimmune, or metabolic injury; cholestatic patterns (ALP, bilirubin) suggest obstruction or infiltration. An AST:ALT ratio >2 with elevated GGT points to alcohol. Interpret hepatitis B serologies systematically: HBsAg indicates infection, IgM anti-HBc acute infection, and isolated anti-HBs immunity.
Pancreatitis, IBD, and celiac
Acute pancreatitis is diagnosed by two of three: characteristic pain, lipase >3 times normal, or imaging. Give early moderate fluids and feed early. Celiac testing requires tissue transglutaminase IgA plus total IgA to exclude deficiency.
Worked example
A patient with cirrhosis has ascites with a SAAG of 1.6 g/dL - portal hypertension, most likely cirrhotic. If the PMN count is 400, treat SBP and start prophylaxis.