What is the best course of action for a 68-year-old female patient with a history of endometriosis, status post (after) hysterectomy, and bladder polyps, presenting with bladder pain?

Imaging for Bladder Pain in a 68-Year-Old Post-Hysterectomy Patient with Endometriosis History

Yes, imaging is indicated, and ultrasound should be the initial modality, with CT abdomen/pelvis with IV contrast as an appropriate alternative or follow-up study if ultrasound is nondiagnostic or if there is concern for broader pathology. 1

Initial Imaging Approach

Ultrasound is the first-line imaging modality for postmenopausal pelvic pain, including bladder-related symptoms. 1 This recommendation is based on:

• Lower radiation exposure (particularly important for chronic conditions requiring potential repeat imaging) 1
• Excellent visualization of pelvic structures including the bladder wall, which can identify endometriotic implants 2
• Cost-effectiveness and widespread availability 1

When to Use CT Abdomen/Pelvis with IV Contrast

CT abdomen/pelvis with IV contrast is "usually appropriate" and may be the preferred initial study in this specific clinical scenario because: 1

• This patient has a history of bladder polyps, which requires evaluation for recurrence or malignancy in the postmenopausal setting 1
• CT has 89% sensitivity for urgent diagnoses in abdominopelvic pain versus 70% for ultrasound 1
• CT is particularly useful when the differential includes both gynecologic and non-gynecologic etiologies (bladder pathology, residual endometriosis, urinary tract issues) 1
• Postmenopausal women with bladder pain require broader evaluation since endometriosis should theoretically regress after menopause, raising concern for other pathology 1

Critical Diagnostic Considerations

Bladder Endometriosis vs. Interstitial Cystitis/Bladder Pain Syndrome

This patient's presentation is highly suspicious for either bladder endometriosis or interstitial cystitis/bladder pain syndrome (IC/BPS), which frequently overlap and may coexist. 3

• Bladder endometriosis accounts for 70-85% of urinary tract endometriosis cases and can persist after hysterectomy if residual endometrial tissue remains 2
• Symptoms of bladder endometriosis are identical to IC/BPS in >70% of cases: urgency (78%), frequency (71%), suprapubic pain (43%) 4
• 42% of patients with bladder endometriosis have a history of treated endometriosis, and 57% were on estrogen therapy at diagnosis 4
• IC/BPS is most commonly diagnosed in the fourth decade or later, with 18-36% having a recent history of UTI 1

Imaging Findings to Evaluate

On ultrasound or CT, look for: 2, 5

• Bladder wall thickening or nodules (endometriotic implants appear as hypoechoic lesions on ultrasound) 2
• Bladder wall masses or polyps (given her history) 1
• Hydronephrosis (silent kidney loss can occur with urinary tract endometriosis) 2
• Residual pelvic endometriotic lesions (particularly deep infiltrating endometriosis) 5

Important Clinical Pitfalls

Do not assume endometriosis has resolved simply because the patient had a hysterectomy. 6, 4 Three of 14 patients (21%) in one series had bladder endometriosis despite prior hysterectomy/oophorectomy. 4

Consider that 57% of patients with bladder endometriosis were on estrogen replacement therapy, which can reactivate residual endometrial tissue. 4 If this patient is on hormone replacement, this significantly increases suspicion for persistent endometriosis. 1

Bladder endometriosis can cause anterior pelvic pain that mimics IC/BPS, with 90% of patients with anterior endometriosis experiencing increased bladder sensation and 70% having painful bladder filling. 5

Recommended Imaging Algorithm

1. Order pelvic ultrasound (transvaginal if feasible, transabdominal if not) as initial study 1
2. If ultrasound shows bladder wall abnormalities, polyps, or is nondiagnostic, proceed to CT abdomen/pelvis with IV contrast 1
3. If CT is equivocal for bladder endometriosis but clinical suspicion remains high, MRI pelvis provides superior soft tissue characterization 2
4. Cystoscopy should be considered if imaging shows bladder wall lesions to directly visualize endometrial implants and obtain tissue diagnosis 4