GI Nutrition

• Audio chapter
  Attending-narrated, listen on the commute.
• ABIM-format MCQs
  5-option vignettes with full wrong-answer teaching.
• Study guide
  Tables, decision trees, primary sources.
• AI tutor
  Chapter-grounded, answers the question you're stuck on.

What this chapter covers

• Section 32.1: Refeeding syndrome

  Refeeding syndrome is the predictable metabolic crisis that follows resumption of carbohydrate after a period of starvation, and it is the highest-yield single decision point in inpatient nutrition.

• Section 32.2: Hospital malnutrition and the albumin trap

  Inpatient nutrition decisions hinge on distinguishing the catabolic state of acute illness from a true nutritional deficit that responds to caloric or protein support.

• Section 32.3: Enteral access and tube-feed complications

  Enteral nutrition requires safe, durable access that matches the planned feeding duration and the patient's anatomy.

• Section 32.4: Parenteral nutrition formulation and complications

  Parenteral nutrition (commonly abbreviated CPN for central parenteral nutrition or TPN when complete) delivers macronutrients (dextrose, amino acids, lipid emulsion), electrolytes, vitamins, and trace minerals through a central venous catheter when the gut is non-functional, inaccessible, or insufficient.

• Section 32.5: Short bowel syndrome and teduglutide

  Short bowel syndrome (SBS) follows extensive small-bowel resection (less than 200 cm of remaining small bowel) and is functionally classified by the anatomy of the residual gut, because the prognosis for enteral autonomy and the trajectory of complications differ sharply by phenotype.

• Section 32.6: Fat-soluble vitamins (A, D, E, K) and EFAs

  Fat-soluble vitamins (A, D, E, K) require bile salts and intact ileal bile-acid recirculation for absorption, so any state that disrupts the enterohepatic bile acid cycle (cholestyramine therapy, ileal disease or resection, severe cholestasis from PBC or PSC, alpha-1 antitrypsin liver disease, cystic fibrosis, prolonged parenteral nutrition without supplementation) creates fat-soluble vitamin deficiency.

• Section 32.7: Water-soluble vitamins

  Water-soluble vitamins are not stored in large quantities, so deficiencies emerge within weeks to months of inadequate intake or absorption.

• Section 32.8: Minerals and trace elements

  Mineral and trace element disorders produce stereotyped phenotypes that the boards test as recognition stems.

Podcast episodes

1. 01

   Refeeding Malnutrition Enteral

   This episode covers the nutrition framework and the enteral access decisions: refeeding syndrome with the NICE high-risk criteria and the cautious calorie reintroduction with prior thiamine, hospital malnutrition diagnosed by GLIM phenotypic plus etiologic criteria with albumin called out as not a nutrition marker, and enteral access selection with its...

2. 02

   Parenteral and Short Bowel

   This episode covers the patient whose gut cannot do the work: parenteral nutrition formulation with its chemistry-driven composition rules, the long-term complications from PNALD and IFALD to catheter infection, and short bowel syndrome with teduglutide and its surveillance requirements.

3. 03

   Vitamins

   This episode covers the fat-soluble and water-soluble vitamin deficiencies: vitamin A night blindness and Bitot spots, D and K, E neuro and hemolysis, thiamine Wernicke encephalopathy preventable with thiamine before glucose, B12 versus folate distinguished by neurology and food sources, and the niacin, pyridoxine, and vitamin C syndromes.

4. 04

   Minerals and Trace Elements

   This episode covers the mineral and trace-element deficiencies: iron, PPI-induced hypomagnesemia, zinc acrodermatitis with altered taste, copper myeloneuropathy especially from zinc excess, selenium cardiomyopathy, and the manganese and chromium problems of long-term parenteral nutrition.