Introduction: Most anal fistulas are crypto-glandular. Nevertheless, anal fistulas can reveal Crohn's disease (CD). The aim of our study was to evaluate the risk of developing CD in patients undergoing surgery for anal fistula.
Patients and methods: All patients undergoing surgery for anal fistula in our center between January 1, 2008 and January 31, 2017 were identified through a prospective administrative database. Demographic, clinical, and laboratory data were retrospectively collected.
Results: Ninety-three patients underwent anal exploration under general anesthesia. The median age at diagnosis of fistula was 43 years (IQR, 34-56) and 27% (n=29) were women. Twenty-seven percent (n=16) had had at least one previous fistula episode. After a median follow-up of 16.8 months (IQR, 7.2-42.0), seven (7.4%) patients were diagnosed with CD. The median time between the diagnosis of fistula and that of CD was 7.6 months (IQR, 2.7, 26.1). Chronic diarrhea (P=0.0003), weight loss (P=0.001), and chronic abdominal pain (P=0.002) were associated with the diagnosis of CD. Characteristics of the fistulas (number, simple/complex, abscess), smoking, extra-digestive manifestations of CD, or a family history of IBD were not associated with the diagnosis of CD.
Conclusion: A medical history of anal fistula surgery resulted in the diagnosis of CD in 7% of cases. Weight loss and the presence of digestive symptoms were associated with the diagnosis of CD. These elements could be used to select patients requiring endoscopic exploration after anal fistula.
Keywords: Abscess; Crohn's disease; Perianal fistula.
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