CT Abdomen and Pelvis with IV Contrast is the Most Appropriate Next Step
For a 28-year-old female with right lower quadrant pain, suprapubic tenderness, mild leukocytosis, and inconclusive ultrasound, proceed directly to CT abdomen and pelvis with IV contrast to establish a definitive diagnosis. 1, 2
Why CT is the Correct Choice
CT abdomen and pelvis with IV contrast achieves 95% sensitivity and 94% specificity for appendicitis and identifies alternative diagnoses in 23-45% of cases presenting with right lower quadrant pain. 1, 2 This patient's clinical presentation—12 hours of pain with mild leukocytosis—places her at intermediate risk for appendicitis, but the differential diagnosis remains broad and includes gynecologic pathology, right-sided diverticulitis, bowel pathology, and urinary tract conditions. 1, 3
The inconclusive ultrasound result is a critical decision point. When ultrasound is nondiagnostic or equivocal, proceeding directly to CT is recommended rather than repeating ultrasound or attempting transvaginal imaging. 4, 2 The staged algorithm of ultrasound followed by CT when needed achieves 99% sensitivity and 91% specificity. 4
Why NOT Transvaginal Ultrasound
While transvaginal ultrasound can be useful in premenopausal women to evaluate gynecologic causes, it should be considered as initial imaging when there is specific clinical concern for acute gynecologic pathology, not after an already inconclusive transabdominal ultrasound. 1 The patient's presentation with suprapubic and right lower quadrant tenderness suggests a broader differential that extends beyond isolated gynecologic pathology. Equivocal ultrasound results require CT anyway, and pursuing additional ultrasound modalities results in diagnostic delay without avoiding the need for definitive imaging. 5
Why NOT Diagnostic Laparoscopy
Diagnostic laparoscopy is premature without definitive imaging confirmation. 1, 5 Clinical determination of appendicitis is notoriously poor, with negative appendectomy rates as high as 25% when relying on clinical assessment alone. 4 This patient lacks classic appendicitis features—no fever, no rebound tenderness—making empiric surgical intervention inappropriate. CT must be obtained first to guide surgical decision-making and avoid unnecessary operative intervention. 1, 2
Why NOT Open Appendectomy
Open appendectomy without imaging confirmation is contraindicated. The absence of fever (present in only 50% of appendicitis cases) and absence of rebound tenderness do not exclude appendicitis, but they also do not confirm it. 4 Multiple alternative diagnoses could explain this presentation, and proceeding directly to appendectomy risks both a negative appendectomy and missing the actual pathology. 1, 3
Critical Clinical Pitfalls to Avoid
- Do not assume inconclusive ultrasound equals normal. Non-visualization of the appendix occurs in 20-81% of cases, creating diagnostic uncertainty that requires CT resolution. 5
- Do not rely on absence of fever to exclude appendicitis. Fever is absent in approximately 50% of appendicitis cases. 4
- Do not delay CT imaging in favor of serial examinations or additional ultrasound modalities. This patient has already had 12 hours of symptoms with an inconclusive initial study—further delay risks progression to perforation if appendicitis is present. 1, 6
Practical Implementation
Order CT abdomen and pelvis with IV contrast immediately. 1, 2 Oral contrast is not mandatory and may delay imaging. 2 While awaiting CT, maintain NPO status, provide IV hydration, and arrange surgical consultation if appendicitis or other surgical pathology is confirmed. 5, 4
The answer is A) CT.