Nutrition in Gastrointestinal, Hepatic, and Renal Disorders
This domain tests organ-specific nutrition logic: when to feed a diseased gut, how to avoid starving a cirrhotic patient, and how to counsel a dialysis patient without creating unnecessary restriction.
Gastrointestinal
- In acute pancreatitis, early oral or enteral feeding within 24–48 hours shortens ileus and hospital stay; NPO is not therapeutic. Mild cases advance diet as tolerated; severe cases use enteral feeding, and nasogastric is acceptable if nasojejunal access is difficult.
- Short bowel syndrome: after massive resection, parenteral nutrition supports the patient while the remnant adapts. Small frequent meals, a sodium-rich oral rehydration solution (90–120 mmol/L sodium), restriction of concentrated sweets, and monitoring for oxalate nephropathy matter. Teduglutide can reduce parenteral needs in selected patients.
- Pediatric Crohn disease responds to exclusive enteral nutrition for induction; low-FODMAP diets target irritable bowel syndrome, not active inflammatory bowel disease. Check vitamin D, B12, and iron.
Hepatic
- Cirrhosis is a catabolic state: 35–40 kcal/kg and 1.2–1.5 g/kg protein. Protein restriction in encephalopathy is obsolete. Offer a late-evening snack to shorten the overnight fast.
- Salt restriction (about 2 g sodium) is used for ascites; fluid restriction applies mainly when sodium is below about 125 mmol/L.
- Severe encephalopathy may require temporary enteral nutrition; lactulose and rifaximin treat precipitants alongside feeding.
Renal
- Nutrition status and dialysis modality drive protein targets; a plant-forward pattern is acceptable with attention to potassium and phosphorus bioavailability. Animal phosphorus is absorbed more efficiently than plant phosphorus.
- Advise phosphate binders with meals, not between meals. Interdialytic weight gain over roughly 4–5% of dry weight signals fluid excess.
Worked example
A 58-year-old man with alcoholic cirrhosis and ascites has a body mass index of 21 kg/m² and muscle wasting. He eats one large evening meal and skips breakfast. Plan: 35 kcal/kg and 1.3 g/kg protein, a 2 g sodium limit, six small feedings including a late-evening snack, and no protein restriction. Thiamine and zinc are replaced.
Traps
Restricting protein in hepatic encephalopathy; keeping a pancreatitis patient NPO; applying a universal potassium ban to all kidney patients; and forgetting that fluid restriction in cirrhosis is only for significant hyponatremia.