What is the initial management approach for diverticulitis?

Initial Management Approach for Diverticulitis

For select patients with acute uncomplicated left-sided colonic diverticulitis, initial management should consist of observation with supportive care (bowel rest and hydration) without antibiotics, while complicated diverticulitis requires antibiotics and possibly drainage or surgery. 1

Classification and Assessment

• Diverticulitis is classified as either uncomplicated (localized inflammation) or complicated (associated with abscess, phlegmon, fistula, obstruction, bleeding, or perforation) 1
• CT scan is the recommended diagnostic test with 98-99% sensitivity and 99-100% specificity for confirming the diagnosis and determining severity 2
• Risk factors for progression to complicated disease include symptoms lasting >5 days, initial pain score >7, vomiting, systemic comorbidity, leukocyte count >13.5 × 10^9 cells/L, high C-reactive protein levels (>140 mg/L), and CT findings of pericolic extraluminal air, fluid collection, or longer inflamed colon segment 1

Management Algorithm for Uncomplicated Diverticulitis

Outpatient Management

• Outpatient management is recommended for clinically stable patients with uncomplicated diverticulitis 1
• Low-certainty evidence shows no differences in risk for elective surgery or long-term diverticulitis recurrence between outpatient and inpatient management 1
• Outpatient management reduces risk of nosocomial infections and offers cost savings of 35-83% per episode 1, 3

Antibiotic-Free Approach

• For select immunocompetent patients with uncomplicated left-sided colonic diverticulitis, initial management without antibiotics is recommended 1
• "Select" patients are defined as those with no systemic inflammatory response, no immunosuppression, not medically frail, able to follow up as outpatients, and with adequate social/family support 1
• Low-certainty evidence shows no differences in diverticulitis-related complications (abscess, fistula, stenosis, obstruction), quality of life, need for surgery, or long-term recurrence between those receiving and not receiving antibiotics 1, 4
• Meta-analyses show no significant difference between observational management and antibiotics treatment in terms of emergency surgery (0.7% vs 1.4%) and recurrence (11% vs 12%) 5

When to Use Antibiotics

• Antibiotics should be reserved for patients with:
  • Complicated diverticulitis 1, 2
  • Systemic inflammatory response 1
  • Immunosuppression 1
  • Persistent fever or chills 2
  • Increasing leukocytosis 2
  • Age >80 years 2
  • Pregnancy 2
  • Chronic medical conditions (cirrhosis, chronic kidney disease, heart failure, poorly controlled diabetes) 2
• First-line oral antibiotics: amoxicillin/clavulanic acid or cefalexin with metronidazole 2
• For patients unable to tolerate oral intake: IV antibiotics (cefuroxime or ceftriaxone plus metronidazole or ampicillin/sulbactam) 2

Management of Complicated Diverticulitis

Small Abscesses (<4-5 cm)

• Initial trial of non-operative treatment with antibiotics alone 1
• Pooled failure rate of 20% and mortality rate of 0.6% 1

Large Abscesses (>4-5 cm)

• Percutaneous drainage combined with antibiotic treatment 1
• When percutaneous drainage is not feasible, antibiotic therapy alone can be considered with careful clinical monitoring 1
• Surgical intervention if patient shows worsening inflammatory signs or if abscess does not respond to medical therapy 1

Peritonitis

• Prompt fluid resuscitation, immediate antibiotic administration, and urgent surgical intervention 6
• Postoperative mortality is 0.5% for elective colon resection and 10.6% for emergent colon resection 2

Supportive Care Measures

• Bowel rest with clear liquid diet initially 2
• Pain management with acetaminophen as first-line 2
• Hydration support 1
• Close monitoring for clinical deterioration 1

Common Pitfalls and Caveats

• Antibiotics may slightly decrease treatment failure rates (defined as "ongoing diverticulitis" within 3 months) compared with no antibiotic treatment 1
• Unnecessary use of antibiotics contributes to antibiotic resistance, a major public health threat 1
• Initial management without antibiotics should be coupled with watchful waiting and continued monitoring of patient status 1
• Patients with isolated pericolic gas (<5 cm from affected colon) may be suitable for non-operative treatment, but elevated CRP is a predictor for treatment failure 1