ACG Clinical Guideline: Colonic Diverticulitis.

Colonic diverticulitis is a common and costly disease, with a lifetime risk of 3%-5%, that drives substantial healthcare use. This guideline provides practical, evidence-based recommendations for the management of diverticulitis in the outpatient gastroenterology setting. Consultations should address diagnosis, typical clinical course, risk factors, the role of antibiotics, and prevention. Computed tomography imaging is essential to confirm the diagnosis of diverticulitis, particularly at the first presentation and in severe cases. After recovery, colonoscopy is recommended for patients with complicated diverticulitis and suggested for those with uncomplicated disease who have alarm symptoms or are not up to date with colorectal cancer screening to rule out an underlying malignancy. Patients treated nonoperatively remain at substantial risk for recurrence, which increases with each episode, whereas complicated diverticulitis most often occurs at the initial presentation. For patients with a history of diverticulitis, lifestyle measures-including a healthy diet (without avoiding nuts, seeds, corn, or popcorn), regular physical activity, achieving or maintaining a healthy weight, avoidance of smoking and heavy alcohol use, and limiting nonsteroidal anti-inflammatory drugs use when possible-may help reduce the recurrence risk. Because randomized trials show little or no benefit, we suggest against routine antibiotics for low-risk patients with acute uncomplicated diverticulitis. Antibiotic use is appropriate for patients with high-risk features, immunocompromise, frailty, or inability to ensure safe outpatient management. Patients with recurrent, uncomplicated diverticulitis that significantly affects quality of life should be referred for surgical consultation to discuss the risks and benefits of elective colon resection.