Should a 67‑year‑old woman with a history of breast cancer and diverticulosis, who had a colonoscopy one month ago and now presents with crampy abdominal pain, diarrhea, and bilateral lower‑abdominal rebound tenderness, be sent to the emergency department for urgent evaluation?

Emergency Department Referral is Mandatory

This patient requires immediate emergency department evaluation given the presence of bilateral lower-abdominal rebound tenderness, which indicates peritoneal irritation and possible complicated diverticulitis. 1

Critical Red Flags Present

This 67-year-old woman demonstrates peritoneal signs (rebound tenderness) that mandate urgent evaluation. The 2022 ACP guidelines explicitly state that outpatient management recommendations do not apply to patients with suspected complicated diverticulitis 1. Her presentation includes:

• Bilateral rebound tenderness = peritoneal irritation suggesting perforation or abscess
• Crampy abdominal pain with diarrhea
• Recent colonoscopy (1 month ago) - though post-colonoscopy diverticulitis is rare (0.029%), it can be serious 2

Why This Cannot Be Managed Outpatient

The ACP guidelines are clear that outpatient management only applies to immunocompetent patients with uncomplicated diverticulitis who have no evidence of systemic inflammatory response 1. Rebound tenderness indicates:

• Possible perforation (emerging or frank)
• Possible abscess formation
• Possible peritonitis requiring urgent surgical evaluation

Patients with signs of peritonitis require fluid resuscitation, rapid antibiotic administration, and urgent surgery 3. The presence of rebound tenderness moves this patient into the complicated diverticulitis category, which requires:

• CT imaging with IV contrast to assess for abscess, perforation, or other complications 1, 4
• Surgical consultation 5
• Intravenous antibiotics 1
• Possible interventional drainage or emergency surgery 3

Additional Risk Factors

Her history of breast cancer raises concern for:

• Potential immunosuppression if she received chemotherapy
• Alternative diagnoses including malignancy (though less likely given recent colonoscopy)
• The need to differentiate between diverticulitis and cancer, which can mimic each other 4

Common Pitfall to Avoid

Do not attempt outpatient management in any patient with peritoneal signs. The guidelines' conditional recommendations for outpatient care explicitly exclude patients with signs suggesting complicated disease 1. Rebound tenderness is an absolute indication for hospital-based evaluation, as 15-30% of patients admitted with acute diverticulitis require surgical intervention during that admission 6.

The emergency department will perform urgent CT imaging to determine if she has perforation, abscess (which may require percutaneous drainage if 3-5 cm or larger), or other complications requiring immediate intervention 3, 7.