In a woman post‑hysterectomy with left lower‑quadrant abdominal pain and CT showing mild bladder wall trabeculation and small bilateral bladder diverticula (no other intra‑abdominal abnormalities), what is the most likely cause and the recommended initial management?

Evaluation of Left Lower Quadrant Pain in Post-Hysterectomy Woman with Bladder Diverticula

The CT findings of mild bladder trabeculation and small bilateral diverticula are incidental and unrelated to the patient's left lower quadrant pain; the most likely cause is diverticulitis that was missed due to the lack of contrast-enhanced imaging, and the patient requires repeat CT with IV and oral contrast to establish the diagnosis. 1

Critical Diagnostic Error: Non-Contrast CT Limitations

• Non-contrast CT has severely limited sensitivity for detecting the inflammatory changes that define diverticulitis, including pericolonic fat stranding, bowel wall thickening, and abscess formation. 1, 2

• The American College of Radiology explicitly states that contrast enhancement is essential for identifying pericolonic inflammation and bowel wall thickening, with sensitivity and specificity approaching 98-100% when properly performed with IV and oral contrast. 1, 2

• The decision to perform imaging without contrast severely compromises diagnostic accuracy and cannot definitively exclude diverticulitis or other inflammatory processes. 1

Most Likely Diagnosis: Uncomplicated Diverticulitis

• In a woman presenting with left lower quadrant pain without other intra-abdominal abnormalities on non-contrast CT, diverticulitis remains the primary diagnostic consideration until proven otherwise with proper contrast-enhanced imaging. 3

• The American College of Physicians recommends abdominal CT imaging when diagnostic uncertainty exists in patients with suspected acute left-sided colonic diverticulitis, which applies directly to this case. 3

• Classic clinical signs include abdominal pain in the left lower quadrant without vomiting, elevated temperature, and tenderness localized to the left lower quadrant. 3

Bladder Findings Are Incidental

• Small bladder diverticula with mild trabeculation are common incidental findings that typically do not cause pain and are most often detected accidentally in postmenopausal women. 4, 5

• The Journal of the American College of Radiology warns against attributing pain to incidental findings like bladder diverticula, as this represents one of the most common diagnostic errors in evaluating left-sided abdominal pain. 1

• Bladder diverticula rarely cause distinct symptoms and are usually managed conservatively unless they become symptomatic with recurrent infections, stones, or malignancy. 4, 6

Recommended Initial Management Algorithm

Step 1: Immediate Contrast-Enhanced CT

• Order CT abdomen and pelvis with IV and oral contrast immediately to definitively diagnose or exclude diverticulitis and identify complications such as abscess formation. 3

• If the patient refuses or has contraindications to contrast CT, MRI abdomen/pelvis with gadolinium is an alternative with 86-94% sensitivity and 88-92% specificity for inflammatory conditions. 1

Step 2: Laboratory Assessment

• Check inflammatory markers including CBC with differential, CRP, and consider procalcitonin to assess for occult inflammation not visible on non-contrast imaging. 3, 1

• Elevated white blood cell count, left shift (>75%), and elevated CRP support the diagnosis of acute diverticulitis. 3

Step 3: Clinical Red Flag Assessment

• Assess for diverticulitis red flags including fever, inability to pass gas/stool, severe tenderness with guarding, vomiting, bloody stools, or leukocytosis, which mandate immediate evaluation regardless of imaging. 1

Step 4: Treatment Based on Contrast CT Results

If Uncomplicated Diverticulitis Confirmed:

• Conservative treatment without antibiotics is recommended for immunocompetent patients with CT-confirmed uncomplicated acute diverticulitis. 3, 2

• For elderly or immunocompromised patients, antibiotic therapy for no more than 7 days is appropriate, using regimens such as ciprofloxacin 400mg IV q12h plus metronidazole 500mg IV q8h, or ertapenem 1g q24h for high-risk patients. 3, 2

If Complicated Diverticulitis (Abscess) Identified:

• Small diverticular abscesses (<3-4cm) can be treated with antibiotics alone for 7 days. 3

• Large abscesses require percutaneous drainage combined with antibiotic therapy for 4 days. 3

Step 5: Follow-Up Colonoscopy

• Plan colonoscopy after symptom resolution (typically 6-8 weeks) to exclude colon cancer, which can mimic diverticulitis, especially important in elderly patients. 2

Common Pitfalls to Avoid

• Never attribute left lower quadrant pain to incidental bladder diverticula without first excluding diverticulitis with proper contrast-enhanced imaging. 1

• Do not use enemas in patients with suspected or confirmed diverticulitis due to significant risk of colonic perforation from increased transmural pressure. 7

• Avoid relying on non-contrast CT findings alone to exclude inflammatory bowel pathology in patients with localized abdominal pain. 1, 2