What is the next step in managing a patient with right iliac fossa (RIF) pain, tenderness in the suprapubic area and RIF, leukocytosis (elevated White Blood Cell (WBC) count), and an inconclusive ultrasound (US)?

CT Abdomen and Pelvis with Contrast is the Next Step

In a patient with RIF pain, leukocytosis (WBC 14), suprapubic tenderness, and an inconclusive ultrasound, proceed directly to CT abdomen and pelvis with IV contrast to establish a definitive diagnosis and guide management. 1

Rationale for CT as the Next Step

The American College of Radiology Appropriateness Criteria explicitly recommend CT abdomen and pelvis with contrast (rating 8/9) as the primary imaging modality for suspected appendicitis with fever and leukocytosis. 1 When ultrasound is inconclusive or negative, CT should be performed to avoid missed diagnoses and unnecessary surgery. 1

Why CT Over Other Options

• CT has superior diagnostic accuracy: Sensitivity and specificity of 95% for appendicitis, compared to ultrasound's 51.8% sensitivity in the general population. 1, 2
• CT identifies alternative diagnoses: In patients where appendicitis is excluded, CT identifies the actual cause in the majority of cases, with 41% requiring hospitalization and 22% requiring surgical or interventional procedures. 2
• Inconclusive ultrasound mandates further imaging: Studies demonstrate that negative or inconclusive ultrasound does not exclude appendicitis—68% of patients with negative ultrasound findings had appendicitis at laparoscopy. 3

Why Not the Other Options

B. Open Appendectomy - Inappropriate Without Definitive Diagnosis

• Negative appendectomy rates are unacceptably high without imaging: Operating based on clinical suspicion alone results in 15-20% negative appendectomy rates. 4
• CT changes management in 43% of cases: Even when appendicitis is clinically suspected, CT frequently identifies alternative diagnoses. 2
• This patient lacks classic peritoneal signs: Absence of rebound tenderness makes the diagnosis less certain, warranting imaging before surgery. 4

C. Diagnostic Laparoscopy - Premature Without Cross-Sectional Imaging

• Laparoscopy is invasive and should be reserved for cases where imaging remains inconclusive after CT. 3
• CT can avoid unnecessary laparoscopy: In one study, admission for observation with repeat clinical assessment and CT imaging avoided 22% of unnecessary appendectomies. 4
• Laparoscopy does not provide the comprehensive evaluation that CT offers for extra-appendiceal pathology including gynecologic, genitourinary, and vascular causes. 2

D. Transvaginal Ultrasound - Limited Utility in This Context

• Transvaginal ultrasound is rated only 5/9 (may be appropriate) by ACR for RIF pain, specifically indicated when pelvic pain suggests gynecologic pathology as the primary concern. 1
• The clinical presentation suggests appendicitis, not primary gynecologic pathology: RIF pain with leukocytosis and suprapubic tenderness is more consistent with appendicitis or other surgical pathology. 1, 5
• Transvaginal ultrasound does not evaluate the appendix or other abdominal structures adequately. 6
• Extra-pelvic findings account for less than 1% of clinically relevant diagnoses in reproductive-age women with RIF pain, making unfocused pelvic imaging inefficient. 6

Clinical Algorithm for This Patient

1. Order CT abdomen and pelvis with IV contrast immediately. 1, 2
2. If CT confirms appendicitis: Proceed to surgical consultation for appendectomy regardless of WBC count. 2
3. If CT shows alternative diagnosis: Manage accordingly (gynecologic pathology, diverticulitis, urinary tract pathology, etc.). 2
4. If CT is negative: Consider observation with serial clinical exams or discharge with close follow-up depending on symptom severity. 4

Important Clinical Caveats

• Never rely on normal or mildly elevated WBC alone to exclude appendicitis: The "classic" presentation occurs in only 50% of patients. 2
• Suprapubic tenderness in this patient may indicate pelvic appendicitis or bladder involvement, which CT will clarify. 1
• Do not delay CT for repeat ultrasound or transvaginal imaging: This wastes time and resources without improving diagnostic accuracy. 1, 6
• Consider low-dose CT protocols to minimize radiation exposure while maintaining diagnostic accuracy. 1