What are the treatment options for side pain radiating to the pelvis?

Side Pain Radiating to Pelvis: Diagnostic and Treatment Approach

The initial evaluation requires ultrasound as the first-line imaging modality, with treatment directed at the underlying cause identified—most commonly urolithiasis (requiring hydration, analgesia, and possible urologic intervention), gynecologic pathology (requiring condition-specific management), or musculoskeletal disorders (requiring conservative management with NSAIDs and physical therapy).

Initial Diagnostic Approach

Clinical Context Matters

The differential diagnosis for side pain radiating to the pelvis varies significantly by patient demographics:

• In reproductive-age women: Gynecologic causes predominate, including ovarian cysts, adnexal torsion, and pelvic inflammatory disease 1
• In postmenopausal women: Ovarian cysts account for one-third of gynecologic causes, uterine fibroids are the second most common cause, and pelvic infection accounts for 20% of cases 2
• Urologic causes: Nephrolithiasis classically presents as flank pain radiating to the groin/pelvis and must be considered in all age groups
• Musculoskeletal causes: Hip fractures (especially in elderly with trauma history) and pelvic insufficiency fractures (particularly post-radiation or with osteoporosis) 3

Imaging Algorithm

First-Line Imaging

Ultrasound (transvaginal and transabdominal combined) is the initial imaging modality of choice for suspected gynecologic or urologic causes 2. This approach:

• Provides anatomic information about uterine size, endometrial canal, fallopian tubes, ovaries, and adnexal masses 2
• Includes Doppler evaluation as a standard component to assess vascularity and distinguish cysts from solid tissue 2
• Offers translabial/transperineal views when vulvar, perineal, or vaginal wall pathology is suspected 2

Second-Line Imaging Based on Clinical Suspicion

For suspected fracture (trauma history, elderly, osteoporosis, post-radiation):

• Plain radiographs of pelvis and hip are initial imaging 2
• MRI pelvis without contrast if radiographs negative but clinical suspicion remains high (90% of fractures visible on plain films, MRI reserved for radiographically occult fractures) 2

For equivocal ultrasound findings or complex pathology:

• MRI pelvis with gadolinium contrast is the problem-solving modality of choice for chronic pelvic pain when ultrasound is nondiagnostic 2
• MRI demonstrates pelvic varices, inflammatory disease, adhesions, and can distinguish inflammatory from neoplastic masses 2

CT abdomen and pelvis may be appropriate when:

• Gynecologic disorder not initially suspected 4
• Ultrasound findings equivocal 4
• Abnormality extends beyond ultrasound field of view 4
• Acute presentation in postmenopausal women where broader differential needed 2

Treatment Based on Etiology

Gynecologic Causes

Ovarian cysts (most common in postmenopausal women):

• Conservative management for simple cysts
• Surgical intervention for complicated cysts, torsion, or rupture 2, 1

Pelvic inflammatory disease:

• Antibiotic therapy targeting causative organisms
• May require drainage if tubo-ovarian abscess present 2

Uterine fibroids (second most common in postmenopausal):

• NSAIDs for pain control (ibuprofen 400 mg every 4-6 hours) 5
• Surgical intervention for torsion of pedunculated fibroids, prolapsed submucosal fibroids, or acute degeneration 2

Adnexal torsion:

• Surgical emergency requiring immediate laparoscopy/laparotomy even if Doppler shows normal vascularity, as torsion can occur despite preserved blood flow 1

Urologic Causes (Nephrolithiasis)

• Hydration and analgesia (NSAIDs preferred: ibuprofen 400-800 mg every 4-6 hours) 5
• Urologic consultation for stones >5mm, obstruction, or refractory pain
• Lithotripsy or ureteroscopy as indicated

Musculoskeletal Causes

Hip/pelvic fractures:

• Orthopedic consultation for surgical fixation planning 2
• Pain management with NSAIDs or opioids as appropriate 5

Pelvic insufficiency fractures (post-radiation, osteoporosis):

• Conservative management with protected weight-bearing
• NSAIDs for analgesia (ibuprofen 400 mg every 4-6 hours) 5, 3
• Physical therapy and rehabilitation once acute pain subsides 3
• Critical pitfall: CT-guided biopsy may be needed to distinguish from metastatic disease, as imaging can be suggestive of malignancy 3

Critical Pitfalls to Avoid

• Do not rely on normal Doppler flow to exclude adnexal torsion—patients with significant pain or risk factors may require exploratory surgery despite normal vascularity 1
• Do not assume plain radiographs exclude fracture—10% of proximal femoral fractures are radiographically occult and require MRI 2
• Do not perform CT as first-line imaging for suspected gynecologic pathology—ultrasound provides superior evaluation with no radiation exposure 2
• In post-radiation patients with pelvic pain, consider insufficiency fractures—failure to diagnose can lead to inappropriate further radiation and prolonged disability 3

Pain Management Across Etiologies

NSAIDs are first-line for most causes:

• Ibuprofen 400 mg every 4-6 hours as needed (doses >400 mg not more effective for pain control) 5
• Maximum daily dose 3200 mg, though most patients respond to lower doses 5
• Administer with food if gastrointestinal complaints occur 5