What investigations would you order for a female presenting with pelvic pain?

Investigations for Female Pelvic Pain

Transvaginal and transabdominal pelvic ultrasound should be the first-line imaging investigation for females presenting with pelvic pain, followed by targeted additional studies based on clinical suspicion and ultrasound findings. 1, 2

Initial Evaluation

Laboratory Tests

• Urine pregnancy test or serum β-hCG (essential first step for all sexually active premenopausal women) 3
• Complete blood count (CBC) with differential
• Comprehensive metabolic panel (CMP)
• Urinalysis with culture if indicated
• C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR)
• Cervical/vaginal swabs for sexually transmitted infections (chlamydia, gonorrhea)

First-Line Imaging

• Transvaginal and transabdominal pelvic ultrasound - provides detailed evaluation of:
  • Uterus (size, endometrial thickness, fibroids, adenomyosis)
  • Adnexa (ovarian cysts, masses, tubo-ovarian abscess)
  • Fallopian tubes (hydrosalpinx, pyosalpinx)
  • Free fluid in pelvis
  • Pelvic venous congestion (dilated pelvic veins >8mm) 1

Additional Investigations Based on Clinical Suspicion

For Suspected Gynecological Causes

• MRI pelvis without and with IV contrast - indicated for:
  • Indeterminate adnexal masses on ultrasound
  • Suspected endometriosis
  • Suspected adenomyosis
  • Pelvic venous disorders (time-resolved postcontrast T1-weighted imaging) 1, 2
  • Suspected pelvic floor dysfunction 1

For Suspected Non-Gynecological Causes

• CT abdomen and pelvis with IV contrast - indicated for:

  • Suspected appendicitis (sensitivity 94%, specificity 94%) 2
  • Suspected diverticulitis
  • Suspected bowel obstruction
  • Undifferentiated acute abdominal pain with negative ultrasound 3

• Non-contrast CT "stone protocol" - indicated for:

  • Suspected urolithiasis (sensitivity 92-99%, specificity 86-93%) 2

For Suspected Pelvic Floor Dysfunction

• Dynamic pelvic floor MRI or MR defecography - indicated for:

  • Suspected pelvic organ prolapse
  • Defecatory dysfunction
  • Recurrent prolapse after surgery 1

• Transperineal ultrasound with dynamic maneuvers - for:

  • Real-time evaluation of pelvic floor dysfunction
  • Assessment of mid-urethral sling or vaginal mesh complications 1

Special Considerations

For Pregnant Patients

• MRI pelvis without contrast is preferred over CT when additional imaging is needed after ultrasound 2

For Postmenopausal Women

• Consider CT urography (CTU) if hematuria is present, as this population has higher risk of urologic malignancy 2

For Suspected Pelvic Inflammatory Disease (PID)

• Lower threshold for imaging as PID is present in 20-50% of women with pelvic pain 4
• Look for specific TVUS findings:
  • Wall thickness >5mm
  • Cogwheel sign
  • Incomplete septa
  • Presence of cul-de-sac fluid 1

Common Pitfalls to Avoid

1. Failing to perform pregnancy testing before imaging or interventions
2. Missing ectopic pregnancy (40% are misdiagnosed at initial presentation) 3
3. Focusing only on gynecologic causes when pelvic pain may be due to gastrointestinal, urologic, or musculoskeletal conditions
4. Overlooking pelvic floor dysfunction which affects 25-33% of postmenopausal women 1
5. Neglecting musculoskeletal assessment when musculoskeletal pain is found in 50-90% of patients with chronic pelvic pain 5

By following this systematic approach to investigating female pelvic pain, clinicians can efficiently identify the underlying cause and initiate appropriate management, improving outcomes and reducing unnecessary procedures.