The clinical characteristics and outcome of intraabdominal abscess in Crohn's disease

Background: We aimed to elucidate the incidence and natural course of abdominal abscess complicating Crohn's disease (CD).

Methods: Of 352 patients with CD who were observed at our hospital between 1985 and October 2001, we studied 35 patients (9.9%) with abscesses in the mid-abdominal region (the abdominal wall, peritoneal cavity, retroperitoneum, and subphrenic region).

Results: The cumulative incidence of complication with an abscess was 9% and 25%, respectively, 10 and 20 years after CD onset. Of the 35 CD patients with abscess, 60% had had surgery by the time of the present study. The age when the abscess developed was 30.1 +/- 8.1 years, and the duration of illness from the onset of CD until development of an abscess was 10.8 +/- 6.3 years (range, 0-29 years). The location of involvement was: abdominal wall, n = 14 (40%); peritoneal cavity, n = 10 (29%); retroperitoneum or iliopsoas, n = 9 (26%); and subphrenic region, n = 2 (6%). In terms of location of abscess, it occurred most often on the right side (65.7%). Almost all abscesses occurred near the site of an anastomosis. Diseased segments of the bowel responsible for abscess formation were categorized radiographically as showing mild stenosis (6.5%), intermediate stenosis and/or simple fistula (41.9%), and severe stenosis and/or multiple fistulas (51.6%). Conservative treatment (including drainage of abscess) alone was effective in 7 patients (20%) and surgery was needed in 28 patients (80%). During the 5.3-year follow-up after treatment for the abdominal abscess, 9 of the 35 patients (26%) had recurrence of an abscess, mostly within 3 years.

Conclusions: Abscess formation was noted in about 10% of patients with CD, with 46% of abscesses occurring in a diseased bowel segment near an anastomotic site. Of the diseased bowel segments responsible for abscess formation, half had neither severe stenosis nor multiple fistulas. Almost all patients underwent surgery for the abscess, and, in more than a quarter of the patients, there was recurrence within a few years after surgery.