What is the most appropriate immediate management for a 64-year-old man with severe left lower abdominal pain, bloody diarrhea, guarding, and a 2 cm × 2 cm pericolic sigmoid collection on CT?

Management of Complicated Sigmoid Diverticulitis with Small Pericolic Collection

This patient requires immediate laparotomy with sigmoidectomy (Option A) given the presence of peritonitis with guarding, severe clinical presentation, and hemodynamic instability implied by the acute surgical abdomen. 1, 2

Clinical Severity Assessment

This 64-year-old man presents with critical features indicating complicated diverticulitis with peritonitis:

• Severe abdominal pain with bloody diarrhea suggests mucosal ischemia or perforation 1, 2
• Significant abdominal tenderness with guarding indicates peritoneal irritation and likely perforation 1
• Anorexia and systemic symptoms suggest sepsis or impending septic shock 2
• 2×2 cm sigmoid collection represents a localized abscess, but the clinical picture dominates management decisions 1

The presence of guarding is the decisive factor—this physical finding indicates peritonitis and mandates surgical intervention regardless of abscess size. 1

Why Emergency Surgery is Required

Peritonitis Overrides Conservative Management

The World Journal of Emergency Surgery strongly recommends against non-operative management in elderly patients with acute left colonic diverticulitis and diffuse peritonitis, stating that prompt and effective source control surgery is mandatory. 1

Guarding on examination indicates peritoneal contamination, which carries mortality rates of 12% with Hartmann's procedure and significantly higher with delayed intervention. 1, 2

Small Abscess Size Does Not Change Surgical Indication

While a 2×2 cm (20 mL) collection would typically be managed with antibiotics alone if the patient were stable without peritonitis 1, the presence of peritoneal signs (guarding) indicates this is not isolated abscess but rather perforation with contamination. 1

The American College of Radiology notes that clinical examination alone misdiagnoses 34-68% of cases, but when peritoneal signs are present, they reliably indicate surgical pathology. 2, 3

Surgical Approach: Sigmoidectomy vs Hartmann's

Laparotomy with sigmoidectomy (resection with primary anastomosis or Hartmann's procedure) is the appropriate intervention, with the specific technique determined intraoperatively based on: 1

• Degree of fecal contamination present in the peritoneal cavity 1
• Patient's hemodynamic stability during surgery 1
• Presence of major comorbidities affecting anastomotic healing 1

Primary Anastomosis Considerations

Resection with primary anastomosis (with or without diverting stoma) is preferred in:

• Clinically stable patients without major comorbidities 1
• Minimal fecal contamination 1
• Adequate tissue perfusion and viable bowel ends 1

Hartmann's Procedure Indications

Hartmann's procedure (resection with end colostomy, no anastomosis) is indicated in:

• Critically ill patients or septic shock 1
• Multiple major comorbidities 1
• Significant fecal peritonitis 1
• Hemodynamic instability despite resuscitation 2

Why Other Options Are Incorrect

Option C (Observation and IV Antibiotics) - Contraindicated

Non-operative management is explicitly contraindicated when peritoneal signs are present. 1

The World Journal of Emergency Surgery provides a conditional recommendation against non-operative management even in cases with distant free air without diffuse fluid, stating failure rates of 10-43%. 1 With guarding present, conservative management would result in progression to septic shock and death. 1, 2

Antibiotics alone fail in 18.7% of abscesses with median size 4 cm in stable patients without peritonitis 1—this patient has peritonitis, making failure virtually certain.

Option D (Laparotomy with Washout Only) - Inadequate Source Control

Washout without resection fails to remove the diseased sigmoid colon, which is the ongoing source of contamination and sepsis. 1

The World Journal of Emergency Surgery emphasizes that "prompt and effective source control surgery" requires resection of the perforated segment. 1 Laparoscopic lavage alone has been studied and shows higher failure rates and mortality compared to resection. 1

Damage control surgery (washout with temporary abdominal closure) is reserved only for patients in extremis who cannot tolerate definitive resection, with planned return for sigmoidectomy once stabilized. 1 This is not the primary surgical approach.

Critical Pitfalls to Avoid

• Do not delay surgery for further imaging or medical optimization when peritoneal signs are present—mortality increases significantly with delayed intervention in septic patients 2
• Do not rely on abscess size alone to guide management; clinical examination findings (guarding) indicate the severity of disease 1, 2
• Do not assume elderly patients can tolerate prolonged conservative management—in-hospital mortality for acute left colonic diverticulitis is 9.7% in patients 65-79 years and 17.8% above 80 years 2
• Do not perform percutaneous drainage when peritonitis is present, as this addresses only the abscess but not the perforated bowel 1

Preoperative Resuscitation

While surgery is urgent, brief preoperative optimization should include: 2

• Aggressive IV crystalloid resuscitation to restore blood pressure >90 mmHg systolic 2
• Broad-spectrum IV antibiotics immediately (carbapenem therapy given severity) 2
• Laboratory studies: CBC, CRP, lactate, blood cultures 2
• Surgical consultation immediately upon diagnosis 2

The goal is resuscitation concurrent with surgical preparation, not delayed definitive treatment. 2