How to manage a patient, likely an older adult with a possible history of abdominal surgery, presenting with both small bowel obstruction and diverticulitis?

Management of Small Bowel Obstruction with Concurrent Diverticulitis

Initial Diagnostic Approach

In an older adult presenting with both small bowel obstruction and diverticulitis, prioritize CT imaging with IV contrast to simultaneously assess both conditions, determine the anatomic relationship between them, and guide immediate management decisions. 1

• Obtain CT scan of abdomen and pelvis with IV contrast as the gold standard diagnostic test, which has 98-99% sensitivity and 99-100% specificity for acute diverticulitis and can simultaneously identify the cause and location of bowel obstruction 1
• In elderly patients with suspected diverticulitis who cannot undergo CT with IV contrast due to severe kidney disease or contrast allergy, use ultrasound, MRI, or CT without contrast as alternative approaches 1
• Assess for adhesive small bowel obstruction (most common cause at 55-75% of cases), which has 85% sensitivity and 78% specificity when there is a history of previous abdominal surgery 1
• Evaluate CT findings for: intestinal wall thickening, pericolonic inflammation, extraluminal gas, intra-abdominal fluid, abscess formation, and the transition point of bowel obstruction 1

Critical Decision Point: Are These Two Separate Processes or Related?

Determine whether the diverticulitis is causing the obstruction or if these are concurrent but unrelated conditions, as this fundamentally changes management.

If Diverticulitis is Causing the Obstruction:

• Colonic diverticulitis with stenosis can cause large bowel obstruction (accounts for 10% of large bowel obstructions) 1
• Small bowel diverticulitis (jejunal or ileal) can directly cause small bowel obstruction through inflammation, enterolith formation, or perforation 2, 3, 4, 5, 6
• Proceed to management algorithm below based on severity

If These are Concurrent Conditions:

• Adhesive small bowel obstruction with incidental colonic diverticulitis requires managing both conditions simultaneously
• The diverticulitis severity determines whether conservative management of the obstruction is safe

Management Algorithm Based on Clinical Presentation

For Uncomplicated Diverticulitis + Partial Small Bowel Obstruction

Initial Conservative Management:

• Place nasogastric tube for decompression (note this is an aerosol-generating procedure requiring appropriate PPE) 1
• Initiate IV fluid resuscitation 1
• Maintain NPO status initially, then advance to clear liquids as tolerated 7
• Attempt conservative management of adhesive small bowel obstruction as usual practice 1

Antibiotic Decision for Diverticulitis Component:

• Do NOT routinely prescribe antibiotics for uncomplicated diverticulitis in immunocompetent elderly patients without systemic inflammation 1, 7
• Reserve antibiotics for elderly patients with: immunocompromised status, temperature >100.4°F, CRP >140 mg/L, WBC >15 × 10^9 cells/L, vomiting, or CT findings of pericolic air bubbles or fluid collection 1, 7
• If antibiotics indicated: Amoxicillin-clavulanate 875/125 mg orally twice daily OR Ciprofloxacin 500 mg twice daily plus Metronidazole 500 mg three times daily for 4-7 days 1, 7

Re-evaluation Timeline:

• Re-evaluate within 7 days, or earlier if clinical condition deteriorates 1
• If no improvement in obstruction after 3-5 days of conservative management, proceed to surgical consultation 1

For Complicated Diverticulitis (Abscess, Perforation) + Small Bowel Obstruction

This requires immediate escalation of care:

• Initiate IV antibiotics immediately with broad-spectrum coverage: Ceftriaxone plus Metronidazole OR Piperacillin-tazobactam 1, 7
• For abscess <4-5 cm: IV antibiotics alone may suffice 1
• For abscess ≥4-5 cm: Percutaneous CT-guided drainage plus IV antibiotics 1
• Continue antibiotics for 3-5 days after adequate source control in immunocompetent patients, or up to 7 days in immunocompromised/critically ill patients 1

Surgical Consultation Criteria:

• Generalized peritonitis or sepsis requires prompt and effective source control surgery 1
• Failed conservative management of bowel obstruction after 3-5 days 1
• Inability to drain abscess percutaneously 1
• CT findings of distant intraperitoneal free air without free fluid (WSES stage 2b) 1
• Diffuse peritonitis (WSES stage 3-4) is an absolute contraindication to non-operative management 1

For Small Bowel Diverticulitis Causing Obstruction

This rare condition (jejunal/ileal diverticulitis) requires different management:

• Small bowel diverticulosis occurs in only 0.02-7.1% of the general population but causes complications requiring surgery in 10% of affected patients 5
• Complications include: diverticulitis, bleeding, perforation, enterolith formation causing obstruction, abscess, and bacterial overgrowth 3, 4, 5
• Surgical options should be discussed early given the possibility of recurrence and serious complications 2
• Surgical treatment options: enterotomy with stone extraction, manual crushing and milking distally, or small bowel resection with primary anastomosis 5
• Small bowel resection is indicated for diverticulitis, bowel perforation, or multiple diverticula 5

Surgical Decision-Making for Elderly Patients

In elderly patients with perforated diverticulitis and generalized peritonitis:

• Hartmann procedure and resection with primary anastomosis are both reasonable options 1
• Hartmann procedure should be preferred in critically ill patients with physiological derangement 1
• In stable elderly patients, primary resection with anastomosis can be performed by experienced surgeons 1
• Damage Control Surgery (emergency laparotomy, source control, open abdomen with vacuum-assisted closure) may be viable in elderly patients with generalized peritonitis and physiological derangement 1
• Avoid laparoscopic lavage in elderly patients with acute peritonitis due to higher risk of failure to control the source of sepsis 1
• Colorectal anastomosis should be avoided in suspected or confirmed COVID-19 patients due to high risk of complications 1

Critical Pitfalls to Avoid

• Do not delay surgery while waiting for COVID-19 swab results if surgery is deemed necessary; use appropriate PPE and proceed 1
• Do not assume all elderly patients with diverticulitis require antibiotics—most with uncomplicated disease do not 1, 7
• Do not extend antibiotics beyond 4 days post-operatively in complicated cases with adequate source control unless the patient is immunocompromised or critically ill 1
• Do not overlook small bowel diverticulitis in elderly patients with mechanical small bowel obstruction without obvious cause 5, 6
• Do not perform elective sigmoid resection based solely on number of previous diverticulitis episodes; base decision on patient-related factors, quality of life impact, and immunocompromised status 1

Special Considerations During Pandemic Conditions

• All acute patients should be considered COVID-19 suspected until proven otherwise 1
• Maximize conservative approach for complicated diverticulitis: IV antibiotics and percutaneous drainage for Hinchey class 1 and 2 1
• Restrict surgery to purulent or fecal peritonitis 1
• Prefer Hartmann procedure over anastomosis in COVID-19 patients 1
• Senior clinician with expertise should conduct initial assessment to promptly recognize whether surgery is required 1