Acute diverticulitis in the young adult is not "virulent.".

Acute diverticulitis historically has been considered rare before the age of 40 but "virulent" when it does occur and frequently requiring emergency operation. Recent experience suggests that the demographics and management of this disease are changing. Outcomes at Kaiser Permanente Los Angeles Medical Center were reviewed. Between January 1997 and July 2001 261 patients were discharged with the diagnosis of acute diverticulitis; 46 or 18 per cent of these were aged < or = 40. Patients' mean age was 35, 76 per cent were men, 65 per cent were Latino, and 72 per cent were obese (body mass index > or = 30 kg/m2). An operation at initial presentation was performed on 35 per cent (16/46) patients. Only 19 per cent of these (3/16) had a correct preoperative diagnosis. The 30 patients who were treated nonoperatively all were managed successfully; one required a percutaneous drain. Given the apparent increasing frequency of acute diverticulitis in young adults and the high success rate of initial nonoperative management surgeons should consider this diagnosis in selected patients who present with abdominal symptoms. Knowledge of typical clinical features and judicious use of computed tomography may decrease the number of unnecessary emergency operations in young adults with acute diverticulitis. Our data do not support a "virulent" label for this disease in the young.