Background : There are no management criteria for optimum out-patient care in mild-to-moderate acute colonic diverticulitis.

Aim : To enable such patients to be managed in an out-patient setting, by establishing criteria and treatment protocols.

Methods : We conducted an open trial and follow-up study from 1997 to 2002. On the basis of ultrasonography, we defined and categorized mild-to-moderate acute colonic diverticulitis ranging from limited inflammation within diverticulum to an abscess < 2 cm in diameter. Subjects were treated as out-patients and followed a 10-day treatment protocol consisting of an oral antibiotic and a sports drink for the first 3 days. Physical examination and laboratory testing helped determine whether or not a patient could resume a liquid diet on day 4, and a regular diet on day 7.

Results : Of the 70 patients, 68 were successfully treated. Two patients required hospitalization. Of the 65 patients who were tracked over several months [median (intraquarter range) = 30.8 (11.9–44.2) months], 16 had one or more clinical recurrences. The medical cost per episode was 80% lower than in-patient treatment.

Conclusions : Patients with mild-to-moderate acute colonic diverticulitis can be safely and successfully treated as out-patients using this protocol.