Diagnostic Approach to Right Lower Quadrant Pain in Young Women

Clinical Context and Diagnostic Considerations

The American College of Radiology recommends CT abdomen and pelvis with IV contrast as the initial imaging study for young women with right lower quadrant pain, given its high sensitivity and specificity for appendicitis and ability to evaluate for gynecologic pathology 1, 2
Ovarian pathology, such as torsion, ruptured cyst, or tubo-ovarian abscess, should be considered in the differential diagnosis, particularly in women of reproductive age with irregular menses 4
Ectopic pregnancy must be excluded in women with irregular menses and right lower quadrant pain, and a urine pregnancy test is essential before imaging 4
Pelvic inflammatory disease is another important consideration in the differential diagnosis of right lower quadrant pain in young women 2

CT abdomen and pelvis with IV contrast has a sensitivity of 95% and specificity of 94% for appendicitis, making it the most appropriate initial imaging study for this patient population 1, 2
The key performance characteristics of CT abdomen and pelvis with IV contrast include a sensitivity of 95% (95% CI: 0.93-0.96) and specificity of 94% (95% CI: 0.92-0.95) for appendicitis 2
Contrast-enhanced CT without enteral contrast achieves 90-100% sensitivity and 94.8-100% specificity for appendicitis, and is equally effective as CT with enteral contrast 6

A urine pregnancy test is mandatory in women of reproductive age with irregular menses to exclude ectopic pregnancy before imaging 4
A complete blood count is expected to show leukocytosis, which supports the diagnosis of appendicitis 6, 3
Urinalysis is essential to exclude urinary tract infection or nephrolithiasis as a cause of right lower quadrant pain 1

If CT confirms appendicitis, the patient should proceed immediately to appendectomy, and IV antibiotics should be initiated at the time of diagnosis 3
If CT shows gynecologic pathology, such as ovarian torsion, ruptured ovarian cyst, or tubo-ovarian abscess, the patient should be managed accordingly, with emergency gynecologic surgery for ovarian torsion, conservative management or gynecology consultation for ruptured ovarian cyst, and IV antibiotics and possible drainage for tubo-ovarian abscess 1
If CT is negative or indeterminate, the patient should undergo clinical reassessment and observation, and consider MRI if high clinical suspicion persists 1, 2, 3