Crohn's Disease

A patient with chronic diarrhea, right lower quadrant pain, fistulas, and mouth sores isn't presenting like UC — the transmural inflammation of Crohn's tells a very different story.

Crohn's disease is a chronic transmural inflammatory bowel disease that can affect any part of the GI tract from mouth to anus, though the terminal ileum and right colon are most commonly involved. The hallmark is skip lesions — patches of inflamed bowel alternating with healthy segments — and cobblestone mucosal appearance on endoscopy. Because inflammation extends through all bowel wall layers, Crohn's creates complications ulcerative colitis cannot: fistulas (bowel-to-bowel, bowel-to-bladder, bowel-to-skin), abscesses, strictures, and obstruction. Nutritional deficits are significant because the terminal ileum absorbs vitamin B12 and bile salts; chronic disease or surgical resection here causes B12 deficiency and fat-soluble vitamin malabsorption. Patients present with chronic diarrhea (often non-bloody), right lower quadrant pain mimicking appendicitis, weight loss, and fatigue. Extraintestinal manifestations include oral aphthous ulcers, erythema nodosum, uveitis, and arthritis. CRP and ESR are elevated during flares. Stool studies rule out infection. Treatment goals center on inducing and maintaining remission using corticosteroids for flares, immunomodulators (azathioprine, methotrexate), and biologics (infliximab, adalimumab). Surgery is not curative — unlike UC — so it is reserved for complications like strictures or fistulas. Nursing priorities include monitoring nutritional status, tracking stool patterns, assessing for fistula drainage, and teaching patients about immunosuppression risks.

Key Distinctions

Don't confuse Crohn's (transmural, skip lesions, any GI segment, fistulas) with UC (mucosal only, continuous from rectum, bloody diarrhea, no fistulas). Students often assume RLQ pain means appendicitis — in a patient with known IBD history, terminal ileum inflammation is far more likely. Surgery cures UC but NOT Crohn's; disease recurs at anastomosis sites after resection.

Clinical Pearl

Think of Crohn's as a "wall-to-wall" problem — transmural inflammation explains every major complication: fistulas bore through, strictures narrow through, abscesses form through all layers.