Diverticulitis, specifically colonic diverticulitis, is a gastrointestinal disease characterized by inflammation of abnormal pouches—diverticula—which can develop in the wall of the large intestine. Symptoms typically include lower abdominal pain of sudden onset, but the onset may also occur over a few days. There may also be nausea; and diarrhea or constipation. Fever or blood in the stool suggests a complication. Repeated attacks may occur.
The causes of diverticulitis are uncertain. Risk factors may include obesity, lack of exercise, smoking, a family history of the disease, and use of nonsteroidal anti-inflammatory drugs (NSAIDs). The role of a low fiber diet as a risk factor is unclear. Having pouches in the large intestine that are not inflamed is known as diverticulosis. Inflammation occurs in between 10% and 25% at some point in time, and is due to a bacterial infection. Diagnosis is typically by CT scan, though blood tests, colonoscopy, or a lower gastrointestinal series may also be supportive. The differential diagnoses include irritable bowel syndrome.
Preventive measures include altering risk factors such as obesity, inactivity, and smoking. Mesalazine and rifaximin appear useful for preventing attacks in those with diverticulosis. Avoiding nuts and seeds as a preventive measure is no longer recommended since there is no evidence these play a role in initiating inflammation in diverticula. For mild diverticulitis, antibiotics by mouth and a liquid diet are recommended. For severe cases, intravenous antibiotics, hospital admission, and complete bowel rest may be recommended. Probiotics are of unclear value. Complications such as abscess formation, fistula formation, and perforation of the colon may require surgery.