What is the appropriate workup for a patient presenting with pelvic pain?

Workup for Pelvic Pain

Begin with serum β-hCG testing in all reproductive-age women, as this single test fundamentally determines whether ultrasound (if positive) or CT (if negative and non-gynecologic causes suspected) should be your initial imaging modality. 1

Immediate Laboratory Testing

• Obtain serum β-hCG in all reproductive-age women presenting with pelvic pain, as it becomes positive ~9 days post-conception and fundamentally alters your diagnostic pathway 1
• A positive β-hCG immediately prioritizes pregnancy-related causes (ectopic pregnancy, spontaneous abortion, placental abruption) and eliminates CT as first-line imaging due to fetal radiation exposure 1
• A negative β-hCG essentially excludes intrauterine or ectopic pregnancy and opens the door to CT imaging if non-gynecologic causes are suspected 1
• Obtain urine culture even with negative urinalysis to detect clinically significant bacteria not identifiable on dipstick 1

Critical History Elements

Document these specific pain characteristics to guide your differential and imaging choice 1:

• Pain duration: Acute (<3 months) versus chronic (≥6 months), as this fundamentally changes your differential 2
• Number of voids per day and constant urge sensation to evaluate urologic causes 1
• Pain location, character, severity and relationship to menstruation to distinguish gynecologic from other etiologies 1
• Associated symptoms: dyspareunia, dysuria, ejaculatory pain, nausea, vomiting, fever to differentiate gynecological from non-gynecological causes 1, 3

Physical Examination Priorities

• Perform brief neurological exam to rule out occult neurologic problems 1
• Evaluate for incomplete bladder emptying to detect retention 1
• Include pelvic floor examination (internal and external) to assess neuromuscular anatomy 3
• Examine lumbosacral spine, sacroiliac joints, pelvis, and hips as musculoskeletal causes are frequently overlooked 3

Imaging Algorithm: The Decision Tree

For Reproductive-Age Women with Suspected Gynecologic Causes:

Ultrasound is your initial imaging modality, providing excellent visualization of ovarian cysts, ovarian torsion, pelvic inflammatory disease, and ectopic pregnancy without radiation exposure 2, 1

• If β-hCG is positive, ultrasound is mandatory as first-line imaging, and CT is contraindicated due to fetal radiation exposure 1
• Ultrasound effectively identifies the most common gynecologic causes in reproductive-age women 2

For Non-Gynecologic or Poorly Localized Pain:

CT abdomen/pelvis with IV contrast should be your initial study when non-gynecological causes are strongly suspected 2, 1

• CT demonstrates 89% sensitivity versus 70% for ultrasound in urgent abdominopelvic diagnoses 2, 1
• CT provides ~88% overall accuracy compared with surgical diagnosis 2, 1
• CT is superior for detecting appendicitis, diverticulitis, inflammatory bowel disease, urinary calculi, and pyelonephritis 1
• Use CT as second-line imaging when ultrasound is equivocal or nondiagnostic 2

For Postmenopausal Women:

The differential shifts significantly in this population 2:

• Ovarian cysts account for one-third of gynecologic pain (slightly less common than reproductive-age women) 2
• Uterine fibroids are the second most common cause (significantly more common than in premenopausal women) due to torsion, prolapse, or acute degeneration 2
• Pelvic infection accounts for 20% of cases, including tubo-ovarian abscess and endometritis 2
• Ovarian neoplasm causes 8% of cases, making malignancy a more prominent concern 2

Ultrasound remains the initial imaging modality for postmenopausal women with suspected gynecologic causes 2

CT or MRI may be appropriate for further characterization of sonographic findings 2

For Chronic Pelvic Pain (≥6 months):

• Ultrasound is the initial imaging modality for deep pelvic pain from pelvic congestion syndrome, intraperitoneal adhesions, hydrosalpinx, or chronic inflammatory disease 2
• MRI may be appropriate for further characterization in select cases, particularly for vaginal, vulvar, or perineal pain with abnormal physical exam 2
• Imaging is primarily indicated in the context of an abnormal physical exam 2

Key Differential Diagnoses by System

Gynecological/Obstetrical:

Hemorrhagic ovarian cysts, ovarian torsion, pelvic inflammatory disease, ectopic pregnancy, spontaneous abortion, placental abruption 1

Non-Gynecological:

Appendicitis, inflammatory bowel disease, infectious enteritis, diverticulitis, urinary tract calculi, pyelonephritis, pelvic thrombophlebitis 1

Chronic Pain-Specific (≥6 months):

Pelvic congestion syndrome, intraperitoneal adhesions, hydrosalpinx, chronic inflammatory disease, cervical stenosis, interstitial cystitis/bladder pain syndrome 2, 1

Critical Pitfalls to Avoid

• Never rely on plain radiographs for pelvic pain evaluation, as they have extremely limited utility 1
• Do not skip β-hCG testing in reproductive-age women, as inadvertent CT in pregnant patients exposes the fetus to unnecessary radiation 1
• Do not overlook vascular causes such as pelvic congestion syndrome and thrombophlebitis that may require specific Doppler protocols 1
• Perform proper hematuria workup in patients with unexplained hematuria or tobacco exposure, given high bladder cancer risk in smokers 1
• Consider cystoscopy only when Hunner lesions are suspected or to exclude bladder cancer, stones, or foreign bodies—not as routine evaluation 1

Special Pregnancy Considerations

• Gadolinium-based MRI contrast is pregnancy category C and should be administered only if potential benefit outweighs risk, as gadolinium is excreted in amniotic fluid and remains for indeterminate periods 1
• Elevated β-hCG in non-pregnant patients may indicate miscarriage, ectopic pregnancy, pituitary production, paraneoplastic production, or gestational trophoblastic disease 1