What is the most appropriate next step for a 28-year-old female with right lower quadrant pain, suprapubic and lower quadrant tenderness, leukocytosis (White Blood Cell count of 12.5), and an inconclusive ultrasound?

CT Abdomen and Pelvis with IV Contrast is the Most Appropriate Next Step

After an inconclusive ultrasound in this 28-year-old female with right lower quadrant pain, fever-equivalent symptoms (12-hour duration), and leukocytosis, CT abdomen and pelvis with IV contrast is the definitive next imaging study. 1, 2

Why CT is the Clear Choice

Diagnostic Performance

• CT achieves sensitivities of 85.7-100% and specificities of 94.8-100% for appendicitis, making it the gold standard after inconclusive ultrasound 1
• The American College of Radiology rates CT abdomen and pelvis with IV contrast as 8-9/9 (usually appropriate) for suspected appendicitis with fever and leukocytosis 1, 2
• CT has reduced negative appendectomy rates from historical 14.7% to 1.7-7.7% 1

Beyond Appendicitis Detection

• CT identifies alternative diagnoses in 40-66% of patients with right lower quadrant pain, including gynecologic pathology, diverticulitis, epiploic appendagitis, inflammatory bowel disease, and urologic conditions 1, 3, 4
• In patients with non-appendiceal diagnoses, 41% required hospitalization, demonstrating the clinical importance of identifying these conditions 1
• Full abdomen and pelvis coverage is essential: 7% of significant pathology occurs outside the pelvis, and limiting imaging to focused pelvic views would decrease sensitivity from 99% to 88% 3

Why Other Options Are Inappropriate

Transvaginal Ultrasound (Option B)

• Transvaginal ultrasound is rated only 2/9 (usually not appropriate) by ACR guidelines for right lower quadrant pain with suspected appendicitis 1
• While appropriate for primary gynecologic concerns, it does not adequately evaluate the appendix or other gastrointestinal pathology 1
• The initial transabdominal ultrasound was already inconclusive, and transvaginal approach adds limited value for appendiceal visualization 1

Diagnostic Laparoscopy (Option C)

• Proceeding directly to diagnostic laparoscopy without definitive imaging risks unnecessary surgery and the morbidity of negative laparotomy 1
• CT imaging before surgery is specifically recommended to avoid the historical 14.7% negative appendectomy rate 1
• Laparoscopy should be reserved for cases where imaging confirms surgical pathology or remains equivocal after optimal imaging 1

Open Appendectomy (Option D)

• Open appendectomy without confirmatory imaging is outdated practice that leads to unacceptably high negative appendectomy rates 1
• This approach would miss alternative diagnoses requiring different management 1, 3

Technical Considerations

Contrast Protocol

• IV contrast without oral/rectal contrast is preferred, achieving sensitivities of 90-100% and specificities of 94.8-100% 1
• Oral contrast delays diagnosis and increases perforation risk without improving diagnostic accuracy 1
• In patients with BMI >25, contrast-enhanced CT without enteral contrast showed 100% sensitivity and 99.5% specificity for appendicitis 1

Common Pitfalls to Avoid

• Do not proceed to surgery based solely on clinical suspicion after inconclusive ultrasound - this leads to unnecessary negative appendectomies 1
• Do not order transvaginal ultrasound as the next step - while this patient is female with suprapubic tenderness, the clinical picture suggests appendicitis as the primary concern, not isolated gynecologic pathology 1
• Do not delay CT for additional ultrasound attempts - ultrasound has a 27.7-45% appendix non-visualization rate, and indirect signs have poor diagnostic performance 1

Answer: A) CT