What is the management plan for a patient with a perforated diverticulum, abscess formation, and multiple other abdominal and systemic findings?

Management of Perforated Sigmoid Diverticulum with Pneumoperitoneum and Abscess

This patient requires urgent surgical intervention with Hartmann's procedure given the presence of pneumoperitoneum from perforated sigmoid diverticulitis with abscess formation, combined with immediate broad-spectrum antibiotics and aggressive resuscitation. 1

Immediate Surgical Decision-Making

The presence of pneumoperitoneum (free intraperitoneal gas) from perforated sigmoid diverticulitis mandates surgical intervention in most cases. 1 While highly selected hemodynamically stable patients with small amounts of distant free gas and no diffuse peritonitis may be candidates for non-operative management with close monitoring, this patient has a 4.14 cm abscess with surrounding fat stranding and pneumoperitoneum, indicating ongoing septic source requiring control. 1

Surgical Approach Selection

For this patient, Hartmann's procedure (sigmoid resection with end colostomy and rectal stump closure) is the recommended surgical approach if the patient is critically ill or has significant comorbidities. 1 The CT findings reveal:

• Pneumoperitoneum with perforated sigmoid diverticulum
• 4.14 cm abscess in right lower quadrant
• Pericolic fat stranding around sigmoid colon
• Minimal ascites suggesting contained but active perforation

If the patient is hemodynamically stable with no major comorbidities, primary resection with anastomosis (with or without diverting loop ileostomy) may be considered. 1 However, given the pneumoperitoneum and abscess formation, Hartmann's procedure remains safer in most real-world scenarios. 1

Alternative: Damage Control Surgery

If the patient is hemodynamically unstable or in physiological extremis, damage control surgery should be performed. 1, 2 This involves:

• Initial limited resection or closure of perforation
• Peritoneal lavage and drainage
• Temporary abdominal closure
• ICU resuscitation for 24-48 hours
• Second-look operation for bowel reconstruction 1, 2

This approach achieves bowel continuity restoration in 76-84% of patients while reducing mortality in unstable patients. 2

Laparoscopic Lavage: NOT Recommended

Laparoscopic peritoneal lavage is NOT recommended as first-line treatment for this patient with perforated diverticulitis and pneumoperitoneum. 1 The SCANDIV, LADIES, and DILALA trials demonstrated that laparoscopic lavage resulted in higher reoperation rates and worse outcomes compared to resection, with no mortality benefit. 1 It may only be considered in very selected patients with purulent (not fecal) peritonitis, which is not clearly established in this case. 1

Antibiotic Therapy

Initiate broad-spectrum intravenous antibiotics immediately covering anaerobes and gram-negative organisms. 1

Antibiotic Regimen Options:

For critically ill or septic patients (which this patient likely is given pneumoperitoneum and abscess):

• Meropenem 1 g IV q6h by extended infusion or continuous infusion 1
• OR Doripenem 500 mg IV q8h by extended infusion 1
• OR Imipenem/cilastatin 500 mg IV q6h by extended infusion 1
• OR Eravacycline 1 mg/kg IV q12h 1

Duration of Antibiotics:

• 4 days if source control is adequate and patient is immunocompetent and not critically ill 1
• Up to 7 days if immunocompromised or critically ill, based on clinical response and inflammatory markers 1, 2
• Patients with ongoing signs of infection beyond 7 days require diagnostic re-evaluation 1

Abscess Management

The 4.14 cm abscess in the right lower quadrant requires source control. 1 Given the pneumoperitoneum indicating active perforation, surgical intervention (as discussed above) will address both the perforation and abscess simultaneously. 1

If percutaneous drainage were considered (which is NOT appropriate here given the perforation), it would only be combined with antibiotics for large abscesses in stable patients without perforation. 1

Critical Pitfalls to Avoid

• Do not attempt non-operative management in patients with large amounts of distant free gas or clinical peritonitis - failure rates approach 57-60%. 1
• Do not perform primary anastomosis in unstable patients or those with fecal peritonitis - this significantly increases mortality. 1
• Do not rely on laparoscopic lavage as definitive treatment - reoperation rates are unacceptably high. 1
• Do not delay surgery for prolonged antibiotic trials - pneumoperitoneum with abscess requires source control. 1, 2

Additional Considerations from CT Findings

Incidental Findings Requiring Follow-up (NOT Urgent):

• Non-calcified pulmonary nodule (0.66 cm) in left lower lobe requires follow-up CT in 6-12 months per Fleischner Society guidelines (general medical knowledge)
• Complex renal cysts (Bosniak IIF) bilaterally require surveillance imaging (general medical knowledge)
• Hepatic cyst in segment 8 is benign and requires no intervention (general medical knowledge)

These findings should be documented for outpatient follow-up after resolution of the acute surgical emergency but do not alter immediate management priorities.

Resuscitation Protocol

Aggressive fluid resuscitation, correction of electrolyte abnormalities, and hemodynamic monitoring are essential prior to and during surgical intervention. 1 The patient should be optimized in the emergency department or ICU with:

• Crystalloid resuscitation
• Correction of any coagulopathy
• Blood product availability
• ICU bed arranged for postoperative care 1, 2