A 24-year-old woman presents to her primary care physician with 6 months of intermittent abdominal pain, non-bloody diarrhea, and a 15-pound weight loss. Her symptoms are associated with fatigue and occasional low-grade fevers. Past medical history is negative, and she takes no medications. Temperature is 37.9°C (100.2°F), blood pressure is 118/74 mm Hg, pulse is 92/min, and respiratory rate is 14/min. Physical examination reveals mild right lower quadrant tenderness to palpation and a small draining perianal lesion. Laboratory studies show a hemoglobin level of 10.8 g/dL and an elevated C-reactive protein level. Colonoscopy demonstrates patchy areas of inflammation separated by normal mucosa. Biopsy reveals transmural inflammation.
Which of the following complications is this patient most likely to develop?
The correct answer is:
B: Fistula formation.
This patient has Crohn disease, as evidenced by chronic diarrhea, weight loss, perianal disease, skip lesions, and transmural inflammation. Because the inflammatory process extends through the full thickness of the bowel wall, Crohn disease predisposes patients to fistulas, abscesses, and strictures. The presence of a draining perianal lesion already suggests fistulizing disease.
Answer choice A: Colorectal adenocarcinoma within 1 year, is incorrect.
Inflammatory bowel disease increases the risk of colorectal cancer, making this answer attractive. However, the risk develops after years of chronic inflammation rather than shortly after diagnosis. Longstanding colonic disease warrants surveillance colonoscopy.
Answer choice C: Toxic megacolon, is incorrect.
Toxic megacolon can occur in Crohn disease but is more strongly associated with severe ulcerative colitis. This answer would be more appropriate in a patient with fulminant colitis, systemic toxicity, and marked colonic dilation.
Answer choice D: Villous atrophy, is incorrect.
Villous atrophy is characteristic of celiac disease rather than Crohn disease. A patient with chronic diarrhea, iron deficiency anemia, and positive tissue transglutaminase antibodies would be more likely to have this finding.
Answer choice E: Watermelon stomach, is incorrect.
Gastric antral vascular ectasia is associated with chronic gastrointestinal blood loss and iron deficiency anemia but is not a complication of Crohn disease.
Key Learning Point
Transmural inflammation is the hallmark of Crohn disease and predisposes patients to fistulas, abscesses, and intestinal strictures.
