Diverticulitis is a common condition. More than 100,000 adults are hospitalized each year with acute diverticulitis. A far greater number have mild (uncomplicated) diverticulitis and are treated without hospitalization. The cornerstone of outpatient treatment is antibiotics, typically given for 7-10 days.

However, recent guidelines published by the American Gastroenterology Association question the need for antibiotics in all cases of uncomplicated diverticulitis, and urge selective use. This recommendation, which is a major shift from long established practice, is based largely on a single randomized trial from Sweden and Iceland. In this study*, 669 patients with uncomplicated diverticulitis were randomized to treatment with or without antibiotics. The use of antibiotics did not affect outcomes, including time to symptom resolution, complications, or recurrence. This is surprising, considering that diverticulitis is traditionally viewed as an infection. But in all likelihood, it’s more an inflammatory, rather than infectious process.

The AGA recommendations cite “low quality” evidence in support of their recommendation, so we need to be cautious in interpreting it. Further studies are certainly needed. And we need to acknowledge the limitations of the existing study, which may not be reflective of real life – all patients had CT scans to confirm the diagnosis and every patient was hospitalized for observation, which is not typical for mild disease.

Still, this study, and the AGA recommendations, likely have a degree of underlying validity. We certainly overuse antibiotics. And antibiotics are not without risk. And if diverticulitis is primarily inflammatory, than maybe antibiotics aren’t essential in mild cases. The truth is, there are many unanswered questions about diverticulitis. Remarkably, we still don’t really understand what leads to diverticulosis (the presence sac-like projections from the colon wall). We don’t fully understand the role of diet, or fiber, though the nut and seed myth has been largely disproven. And it’s not clear what causes a diverticulum to become inflamed.

Overall, there is still a lot to learn about diverticular disease, and the latest guidelines lead us to further question current practice. Should we stop using antibiotics? No. But exercising antibiotic stewardship is reasonable goal, in select cases.

-Christopher McGowan, MD

*Chabok A, Pahlman L, Hjern F, et al. Randomized clinical trial of antibiotics in acute uncomplicated

diverticulitis. Br J Surg 2012;99:532-39.