What is the evaluation and treatment approach for a patient presenting with right-sided pelvic pain?

Evaluation and Treatment of Right-Sided Pelvic Pain

For patients presenting with right-sided pelvic pain, CT of the abdomen and pelvis with IV contrast is the recommended initial imaging study for non-pregnant patients, while transvaginal and transabdominal ultrasound is the first-line imaging choice for pregnant patients or when gynecologic etiology is suspected. 1

Diagnostic Approach

Initial Assessment

• Obtain pregnancy status with β-hCG testing in all women of reproductive age before imaging 1
• Assess for fever, leukocytosis, and specific location of pain
• Consider both gynecologic and non-gynecologic causes:
  • Gynecologic: Ovarian cysts, adnexal torsion, PID, ectopic pregnancy
  • Non-gynecologic: Appendicitis, diverticulitis, urolithiasis, inflammatory bowel disease

Imaging Algorithm

1. If pregnancy test positive:

   • Transvaginal and transabdominal ultrasound is first-line imaging 1
   • Avoid CT due to radiation exposure concerns

2. If pregnancy test negative and gynecologic etiology suspected:

   • Transvaginal and transabdominal ultrasound is first-line imaging 1
   • Ultrasound findings suggestive of adnexal torsion include:
     • Enlarged ovary with stromal edema
     • Absent/diminished ovarian enhancement on Doppler
     • Peripheralized follicles
     • Tubal thickening

3. If pregnancy test negative and non-gynecologic etiology suspected:

   • CT abdomen and pelvis with IV contrast is first-line imaging 1
   • CT has excellent diagnostic accuracy for appendicitis (95% sensitivity, 94% specificity) 1
   • CT can identify alternative diagnoses including:
     • Benign adnexal masses
     • Colitis
     • Inflammatory bowel disease
     • Constipation
     • Urolithiasis

4. If urolithiasis is suspected:

   • Non-contrast CT abdomen and pelvis is preferred (sensitivity 97-100%) 2
   • Ultrasound with color Doppler can be considered in patients with contraindications to radiation 2

Common Pitfalls and Caveats

• Don't miss gynecologic emergencies: Adnexal torsion and ruptured ectopic pregnancy require urgent intervention
• Beware of normal Doppler findings: Adnexal torsion can occur despite normal vasculature on ultrasound with Doppler 3
• Don't rely solely on clinical presentation: Misdiagnosis based on clinical assessment alone is common, with studies showing error rates of 34-68% for conditions like diverticulitis 1
• Consider alternative diagnoses: Right colonic diverticulitis (8% of RLQ pain cases) and bowel obstruction (3% of RLQ pain cases) can mimic appendicitis 2
• Radiation exposure: Consider ultrasound as initial imaging for young patients when appropriate to reduce radiation exposure 1

Treatment Approach

Treatment depends on the specific diagnosis:

1. Appendicitis: Surgical consultation for appendectomy
2. Adnexal torsion: Urgent gynecologic consultation for surgical detorsion
3. Ovarian cysts: Conservative management for simple cysts; surgical intervention for complicated or symptomatic cysts
4. Pelvic inflammatory disease: Antibiotic therapy; hospitalization for severe cases
5. Urolithiasis: Pain management and hydration for stones <5mm; urologic consultation for larger stones or obstruction 2
6. Diverticulitis: Antibiotics for uncomplicated cases; surgical consultation for complicated cases

Follow-up Recommendations

• For patients with persistent symptoms despite negative initial imaging, consider:
  • Alternative imaging modalities (MRI for better soft tissue evaluation)
  • Gynecologic consultation for diagnostic laparoscopy if gynecologic etiology suspected
  • Urologic consultation for persistent urinary symptoms
  • Gastroenterology consultation for persistent gastrointestinal symptoms

The comprehensive evaluation of right-sided pelvic pain requires careful consideration of both gynecologic and non-gynecologic causes, with imaging selection guided by clinical suspicion and pregnancy status.