Inflammatory Bowel Disease
Core concepts
Separate ulcerative colitis (mucosal, continuous, rectal involvement, curative proctocolectomy) from Crohn disease (transmural, skip lesions, fistulizing, recurrence after surgery). Understand the role of medical therapy escalation, biologic agents, and when surgery becomes indicated: medically refractory disease, dysplasia/cancer, stricture, toxic megacolon, hemorrhage. Know pouch surgery (IPAA) indications, complications (pouchitis, cuffitis, fistula), and the importance of excluding Crohn disease before pouching. Recognize extraintestinal manifestations and their correlation with disease activity.
Traps
Questions test whether you avoid operating on active perianal Crohn fistula with aggressive seton and diversion rather than proctectomy. Another trap: attributing bloody diarrhea with rectal sparing to UC. Also watch for the misconception that surgery cures Crohn disease. Dysplasia surveillance in long-standing colitis (chromoendoscopy, random biopsies) is frequently probed.
Worked example
A patient with 12 years of pancolitis and a flat high-grade dysplasia on surveillance: recommend colectomy, not continued surveillance, because multifocal or flat high-grade dysplasia carries high cancer risk. Rule of thumb: in colitis, flat dysplasia equals field defect; visible polypoid lesions may be resected if completely excised with negative margins in selected cases.