CT Abdomen and Pelvis with IV Contrast is the Next Step
For a patient presenting with right lower quadrant pain, tenderness, and rebound tenderness, CT abdomen and pelvis with IV contrast should be obtained before proceeding to surgery. 1, 2
Why Imaging Before Surgery is Critical
The negative appendectomy rate without preoperative imaging is unacceptably high at 14.7-25% when relying on clinical examination alone. 1, 2 Preoperative CT dramatically reduces this rate to 1.7-7.7%, preventing unnecessary surgeries and their associated complications. 2, 3
Even with classic clinical presentation (right lower quadrant pain, tenderness, and rebound), imaging remains essential because:
- Classic presentation occurs in only approximately 50% of actual appendicitis cases 2
- CT identifies alternative diagnoses in 23-45% of patients with right lower quadrant pain and classic symptoms, fundamentally changing management 2, 4
- Alternative diagnoses frequently detected include right colonic diverticulitis (8%), ureteral stones, intestinal obstruction (3%), gynecologic pathology (21.6%), and other gastrointestinal conditions (46%) 2
Diagnostic Performance of CT
CT abdomen and pelvis with IV contrast demonstrates:
- Sensitivity: 85.7-100% 1, 2, 4
- Specificity: 94.8-100% 1, 2, 4
- High accuracy for detecting perforation and abscess formation 2
CT without enteral contrast is equally effective (sensitivity 90-100%, specificity 94.8-100%) and allows for rapid diagnosis without delays from oral contrast administration. 2
Why Other Options Are Inappropriate
Open appendectomy (Option A) without imaging:
- Leads to 14.7-25% negative appendectomy rate 1, 2
- Misses alternative diagnoses requiring different management 2
- Exposes patients to unnecessary surgical risks 1
Antibiotics alone (Option C):
- Cannot be initiated without confirmed diagnosis 2
- Risks delaying appropriate treatment for alternative pathology 2
IV fluid and 24-hour observation (Option D):
- Inappropriate for patients with peritoneal signs (rebound tenderness) 2
- Delays definitive diagnosis and treatment 1
- Only appropriate for low-risk patients without rebound tenderness 2
Clinical Pitfall to Avoid
Do not rely on absence of fever to exclude appendicitis—fever is absent in approximately 50% of appendicitis cases. 2 The presence of rebound tenderness indicates peritoneal irritation and warrants immediate imaging, not observation. 2
Management Algorithm After CT
- If CT confirms appendicitis: Proceed to surgical consultation and initiate IV antibiotics 2, 4
- If CT shows alternative diagnosis: Manage accordingly (e.g., gynecologic surgery for ovarian torsion, antibiotics for diverticulitis) 4
- If CT is negative/indeterminate: Clinical reassessment with serial examinations and mandatory 24-hour follow-up 2