In a 66‑year‑old woman with left lower abdominal pain and CT showing mild bladder wall trabeculation and small bilateral bladder diverticula but otherwise normal abdominal and pelvic findings, what is the most likely cause of her pain and what is the recommended next step in management?

Most Likely Cause and Next Steps

In this 66-year-old woman with left lower quadrant pain and an otherwise normal CT scan showing only mild bladder trabeculation and small bilateral bladder diverticula, the bladder findings are incidental and unrelated to her acute pain—you must now pursue alternative diagnoses including functional bowel disorders, early diverticulitis not yet visible on imaging, or gynecologic pathology. 1

Why the Bladder Findings Are Not the Cause

• Bladder trabeculation and small diverticula are typically asymptomatic findings that do not cause acute left lower quadrant pain unless complicated by infection, stones, or tumor—none of which are present on this CT. 2, 3

• Bladder trabeculation in postmenopausal women is most commonly associated with chronic bladder outlet obstruction from pelvic organ prolapse (which this patient does not have, given her prior hysterectomy) or detrusor overactivity causing urinary urgency and frequency—not acute abdominal pain. 3

• Small bladder diverticula are incidental findings in 7% of patients with refractory urinary symptoms and do not correlate with acute pain unless they become infected or harbor malignancy. 2

Differential Diagnosis for Her Pain

Early or Atypical Diverticulitis

• CT has 98% sensitivity for diverticulitis, but very early inflammatory changes may be missed on a single scan, particularly if imaging was performed within the first 24-48 hours of symptom onset. 1, 4

• The absence of diverticulosis on this CT does not exclude sigmoid diverticulitis as a cause, since small diverticula may not be visible and inflammation can precede obvious structural changes. 1

• If pain persists beyond 2-3 days or worsens, obtain repeat CT abdomen/pelvis with IV contrast to reassess for evolving diverticulitis or other complications. 1

Functional Bowel Disorder

• Functional bowel disorders become the leading diagnosis when structural pathology has been excluded by CT, particularly in patients over 50 years without alarm features. 4

• Ask specifically about pain related to bowel movements, dietary triggers, or relief with defecation—these features point toward irritable bowel syndrome. 4

• Constipation-predominant symptoms warrant a trial of dietary fiber, while pain-predominant symptoms may respond to antispasmodic medications. 4

Gynecologic Pathology

• Even in a post-hysterectomy patient, ovarian pathology (cyst, torsion, mass) remains possible and can present with left lower quadrant pain. 1, 5

• Order pelvic/transvaginal ultrasound if not already performed to evaluate the adnexa, as CT may miss small ovarian lesions or functional cysts. 1, 4

• Cyclical pain patterns suggest residual ovarian pathology requiring gynecologic evaluation. 4

Other Considerations

• Epiploic appendagitis can mimic diverticulitis with left lower quadrant pain but appears on CT as a pericolic fatty mass with a hyperattenuated rim—not present here. 1

• Pyelonephritis or nephrolithiasis should be excluded with urinalysis, though the CT shows no hydronephrosis or perinephric stranding. 1, 6

Recommended Next Steps

Immediate Laboratory Workup

• Order CBC with differential, CRP, and urinalysis to assess for occult infection or inflammation not yet visible on imaging. 6

• A CRP >50 mg/L combined with left lower quadrant tenderness and absence of vomiting has 97% accuracy for diverticulitis, even when CT is initially negative. 6

• Leukocytosis with left shift (≥75% neutrophils) suggests bacterial infection and warrants closer monitoring or repeat imaging. 6

Clinical Monitoring

• If pain is mild, stable, and the patient can tolerate oral intake without fever or peritoneal signs, conservative outpatient management is appropriate. 1

• Instruct the patient to return immediately if fever, inability to pass gas/stool, vomiting, severe tenderness with guarding, or bloody stools develop—these are red flags requiring emergency evaluation. 1

Repeat Imaging Indications

• Obtain repeat CT abdomen/pelvis with IV contrast if symptoms persist >2-3 days, worsen, or new concerning features develop (fever, peritoneal signs, inability to eat). 1

• Repeat imaging is critical because clinical examination alone misdiagnoses 34-68% of cases, and early diverticulitis may evolve over 48-72 hours. 1, 6

Gynecologic Evaluation

• Order pelvic/transvaginal ultrasound to exclude ovarian pathology if pain persists and repeat CT remains negative. 1, 4

• Refer to gynecology if ultrasound reveals any adnexal mass or if high clinical suspicion remains despite negative imaging. 4

Gastroenterology Referral

• Refer to gastroenterology if pain becomes chronic (>4-6 weeks) and all imaging remains negative, as functional bowel disorder management may require specialized care. 4

• Colonoscopy is indicated if the patient is not up-to-date with age-appropriate screening (last colonoscopy >10 years ago or never performed), or if alarm features develop (weight loss, anemia, change in bowel habits). 4

Critical Pitfalls to Avoid

• Do not attribute acute left lower quadrant pain to incidental bladder trabeculation or small diverticula—these are chronic findings unrelated to acute pain unless complicated. 2, 3

• Do not assume the CT has definitively ruled out all pathology—early diverticulitis, small ovarian lesions, and functional disorders may not be visible on a single scan. 1, 4

• Do not delay repeat imaging if symptoms persist or worsen—relying on clinical assessment alone leads to missed diagnoses in up to 68% of cases. 1, 6

• Do not perform cystoscopy or urologic workup for the bladder findings unless the patient develops recurrent UTIs, hematuria, or urinary retention—these incidental findings do not require intervention. 2