Patient presentation
A 55-year-old man presents with acute onset of left lower quadrant abdominal pain, fever, and changes in bowel habits including constipation. He reports a history of chronic constipation and occasional prior episodes of abdominal pain.
On examination he has localized tenderness and guarding in the left lower quadrant. You must evaluate him for evidence of complicated disease—abscess, fistula, or free perforation—and decide between medical management, percutaneous drainage, and urgent operation.
What you'll be asked — and what a strong resident discusses
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What is your differential diagnosis for this presentation, and what features point toward diverticulitis?
Expected answer
Acute sigmoid diverticulitis is most likely given the LLQ pain, fever, altered bowel habits, and localized tenderness/guarding. Differential includes colon cancer, inflammatory bowel disease (Crohn's), ischemic or infectious colitis, ureteral colic, and in a complicated picture, perforation with abscess. The age (55), chronic constipation, and prior similar episodes support recurrent diverticular disease, but cancer must always be excluded later with colonoscopy.
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What initial workup do you order and what specifically are you looking for on imaging?
Expected answer
CBC with differential, basic metabolic panel, lactate, and urinalysis. CT of the abdomen and pelvis with IV (and oral if available) contrast is the study of choice. I am looking for pericolic fat stranding, bowel wall thickening, abscess formation, extraluminal air/free air (pneumoperitoneum), and free fluid—features that distinguish uncomplicated from complicated disease and that drive management.
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The CT shows pericolic fat stranding and sigmoid wall thickening but no abscess or free air, and he is hemodynamically stable. How do you manage him?
Expected answer
This is uncomplicated diverticulitis. Manage with antibiotics covering gram-negative and anaerobic organisms. If he is hemodynamically stable, immunocompetent, socially reliable, and can tolerate a diet, outpatient oral antibiotics are reasonable; otherwise admit for IV antibiotics and bowel rest. Arrange colonoscopy in 6–8 weeks (no sooner than 6 weeks) to exclude cancer or Crohn's, since he has not had recent endoscopic evaluation.
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Suppose CT instead shows a 5 cm pericolic abscess. What is your management?
Expected answer
For an abscess 3 cm or larger, image-guided percutaneous drainage plus broad-spectrum antibiotics is recommended. This controls the source, often avoids urgent operation, and allows for an elective single-stage resection later. Smaller abscesses (<3 cm) can often be managed with antibiotics alone. Follow-up colonoscopy and consideration of elective resection are planned after recovery.
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Now the patient develops diffuse peritonitis and CT shows free intraperitoneal air. What do you do?
Expected answer
Generalized peritonitis from free perforation is a surgical emergency. After rapid resuscitation—IV fluids, broad-spectrum antibiotics, foley, NGT as needed—he needs urgent operative intervention, not further temporizing. I would proceed to the OR for sigmoid colectomy. Resuscitation and operation happen in parallel; you do not delay the operation for an unstable, peritonitic patient.
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You're in the OR with diffuse feculent contamination and an unstable patient. What operation do you perform and why?
Expected answer
Hartmann's procedure—sigmoid resection with a stapled rectosigmoid stump and end descending colostomy. It is the safest option because it avoids an anastomosis in a hostile, contaminated field and in a physiologically unstable patient. An anastomosis is contraindicated with widespread feculent contamination because of the high leak risk.
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When would primary anastomosis (with or without diverting loop ileostomy) be acceptable instead of Hartmann's?
Expected answer
In a stable patient with limited (purulent rather than gross feculent) contamination, sigmoid resection with on-table colonic lavage and a colorectal anastomosis—possibly protected by a diverting loop ileostomy—can be considered. This avoids the morbidity of a future Hartmann's reversal. The decision is based on the patient's physiologic status and the degree of contamination.
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For an elective resection (recurrent or fistulizing disease), what are the technical principles?
Expected answer
Remove the entire sigmoid and rectosigmoid colon and create a true colorectal anastomosis (distal margin on the rectum, not a colocolostomy). Failure to remove the rectosigmoid is associated with higher leak rates and recurrent diverticulitis. If the surgeon is skilled in advanced laparoscopy, a minimally invasive approach is preferred. Fistulas (e.g., colovesical) and strictures are indications for resection.
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How does immunocompromise or the presence of a colovesical fistula change your plan?
Expected answer
Immunocompromised patients have higher risk of complicated disease and poorer response to nonoperative management, lowering the threshold for admission, IV antibiotics, and surgery. A colovesical fistula (pneumaturia/fecaluria) is an indication for elective resection of the sigmoid/rectosigmoid with repair of the bladder defect, after CT confirmation and colonoscopy to exclude malignancy.
What residents often miss
- Sending an unstable, peritonitic patient for additional imaging or prolonged nonoperative management instead of resuscitating and taking them urgently to the OR (an automatic-fail error).
- Performing a primary anastomosis in the setting of widespread feculent contamination or hemodynamic instability rather than a Hartmann's procedure.
- Failing to remove the rectosigmoid colon during resection, leaving a colocolostomy and risking anastomotic leak and recurrent diverticulitis.
- Performing colonoscopy during or immediately after acute diverticulitis instead of waiting 6–8 weeks—risking perforation and missing the chance to exclude cancer/Crohn's at the appropriate time.
- Treating a drainable abscess (≥3 cm) with antibiotics alone instead of arranging percutaneous drainage.
- Omitting anaerobic coverage or delaying antibiotics in complicated/perforated disease.
- Forgetting to risk-stratify for outpatient management—sending home an immunocompromised, unreliable, or diet-intolerant patient who should be admitted.
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This page is educational content for general-surgery board-exam practice. It is not medical advice and is not a substitute for clinical judgment, institutional protocols, or current primary literature.