Acute terminal ileitis, yersiniosis, and Crohn's disease: a long-term follow-up study of the relationships.

Background: During the past decade, very little has been published on the relationships between Yersinia enterocolitica, acute terminal ileitis (ATI), and Crohn's disease, possibly due to a decrease in Yersinia infections and, consequently, in ATI. Methods: Fifty-three patients admitted to Herlev University Hospital during the period 1976-1998 were diagnosed as having ATI while undergoing surgery for suspected acute appendicitis. The patients were followed up, and both Yersinia titers and the development of Crohn's disease were registered. Results: Forty-four patients (83%) were tested for Yersinia, 17 of whom (39%; 95% confidence limits, 24-55%) were positive. The incidence of yersiniosis in ATI decreased significantly during the observation period (P<0.05), whereas the incidence of ATI itself was unchanged. Thirteen of the 53 patients (25%; 95% confidence limits, 14-38%) had, in addition to ATI, an inflamed appendix. Three patients developed Crohn's disease during a median observation period of 13 years (cumulative risk 6.1%). None of them had yersiniosis. Conclusions: The incidence of ATI remained stable during the observation period, even though the number of Yersinia infections decreased. This may have been due to an increase in gastrointestinal infections caused by other enteric pathogens. In accordance with previous findings, ATI patients who developed Crohn's disease did not have yersiniosis. Thus, it is still of prognostic value to test patients with ATI for Yersinia and perhaps for other enteric pathogens as well.