Crohn’s disease

1. Big picture

Crohn’s disease is a chronic relapsing inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal tract from mouth to anus, but most commonly affects the terminal ileum and ileocecal region. The inflammation is transmural, discontinuous, and patchy, producing skip lesions, strictures, fistulas, abscesses, and malabsorption.

Classic exam pattern:

Young patient + chronic diarrhea + right lower quadrant pain + weight loss ± fever ± perianal disease.

The most important contrast is with ulcerative colitis:

| Feature | Crohn’s disease | Ulcerative colitis | | -------------------