From the Guidelines
Antibiotics should not be prescribed routinely for immunocompetent patients with uncomplicated acute diverticulitis, but rather reserved for those with comorbidities, refractory symptoms, or signs of systemic inflammation, such as a CRP >140 mg/L or baseline white blood cell count > 15 × 10^9 cells per liter. According to the most recent guidelines, including the 2021 AGA clinical practice update on medical management of colonic diverticulitis 1, antibiotics are not necessary for the treatment of uncomplicated disease in immunocompetent patients.
Treatment Approach
The treatment approach for acute diverticulitis depends on the severity of the disease. For mild cases, treatment can be managed at home with rest, a liquid diet transitioning to low-fiber foods, and symptomatic relief. Patients should take acetaminophen for pain rather than NSAIDs, which may increase complications. Clear liquids should be consumed for 2-3 days, gradually adding low-fiber foods like white rice, pasta, and lean meats before returning to a normal diet.
Antibiotic Use
When antibiotic treatment is necessary, the regimen usually includes broad-spectrum agents with gram-negative and anaerobic coverage. In the outpatient setting, treatment of mild uncomplicated diverticulitis most commonly includes either a combination of an oral fluoroquinolone and metronidazole or monotherapy with oral amoxicillin-clavulanate, typically for 4-7 days 1. The 2020 update of the WSES guidelines for the management of acute colonic diverticulitis in the emergency setting also supports the selective use of antibiotics, recommending against routine antibiotic therapy in immunocompetent patients with uncomplicated diverticulitis 1.
High-Risk Patients
Patients who are immunocompromised, have signs of systemic inflammation, or present with complicated diverticulitis (such as abscess, perforation, or obstruction) should be treated with antibiotics. Additionally, patients with risk factors for progression to complicated diverticulitis, including baseline ASA score III or IV, duration of symptoms longer than 5 days, presence of vomiting, CRP >140 mg/L, and baseline white blood cell count > 15 × 10^9 cells per liter, should also receive antibiotic treatment 1.
Prevention of Recurrence
After recovery, a high-fiber diet (25-30g daily) with adequate hydration helps prevent recurrence by reducing pressure in the colon. Patients should seek immediate medical attention if they experience severe abdominal pain, persistent fever, inability to keep fluids down, or rectal bleeding, as these may indicate complications requiring urgent intervention.
From the Research
Definition and Classification of Acute Diverticulitis
- Acute diverticulitis is a complication of diverticulosis, which is a common condition affecting the large bowel in western countries 2.
- It is classified as uncomplicated or complicated based on the presence of abscesses, perforation, or peritonitis 3, 4.
Treatment of Uncomplicated Acute Diverticulitis
- Outpatient treatment is recommended for afebrile, clinically stable patients with uncomplicated diverticulitis 3.
- Antibiotics have no proven benefit in reducing the duration of the disease or preventing recurrence, and should only be used selectively 5, 3.
- Bowel rest and observation are often sufficient for uncomplicated cases 4.
Treatment of Complicated Acute Diverticulitis
- Non-operative management, including bowel rest and intravenous antibiotics, is indicated for small abscesses 3, 4.
- Larger abscesses should be drained percutaneously, and patients with peritonitis and sepsis should receive urgent surgery 3, 4.
- Surgical intervention, such as Hartmann procedure or primary anastomosis, may be necessary for peritonitis or failure of non-operative management 3, 4.
Role of Antibiotics in Acute Diverticulitis
- The use of antibiotics in uncomplicated acute diverticulitis is uncertain, with low-certainty evidence suggesting little or no difference in complications or emergency surgery 5.
- Antibiotics are recommended for complicated diverticulitis, particularly for patients with abscesses or peritonitis 2, 3.
Follow-up and Prevention
- Colonoscopy is recommended for all patients with complicated diverticulitis 6 weeks after CT diagnosis of inflammation, and for patients with uncomplicated diverticulitis who have suspicious features on CT scan or who otherwise meet national bowel cancer screening criteria 3.
- Elective surgery may be indicated for patients with ongoing symptoms, pelvic abscesses, or complications such as fistulating disease or recurrent diverticular bleeding 4.