Management of Young Girl with Right Lower Quadrant Pain and Normal/Near-Upper Limit WBC
Proceed immediately to CT abdomen and pelvis with IV contrast—normal or near-normal WBC count does NOT exclude appendicitis or other surgical pathology, and imaging is mandatory regardless of laboratory values. 1, 2
Critical Clinical Context
- Never rely on normal WBC alone to exclude appendicitis—classic symptoms (fever and leukocytosis) occur in only approximately 50% of appendicitis cases 1, 2, 3
- The absence of fever and normal WBC are common in early appendicitis and do not rule out the diagnosis 3
- Clinical determination of appendicitis is notoriously poor, with negative appendectomy rates as high as 25% when relying on clinical assessment alone 2, 3
Recommended Diagnostic Algorithm
First-Line Imaging Approach
For adolescent/young girls with RLQ pain:
- Start with ultrasound as initial imaging to avoid radiation exposure, particularly valuable in pediatric patients due to less body fat allowing better visualization 2, 3
- Ultrasound achieves 76-87% sensitivity and 83-89% specificity for appendicitis in children 3
- Ultrasound also effectively identifies gynecologic pathology, which is a common alternative diagnosis in reproductive-age females 1
If Ultrasound is Nondiagnostic or Equivocal
- Proceed directly to CT abdomen and pelvis with IV contrast 1, 2
- CT provides superior diagnostic accuracy: 85.7-100% sensitivity and 94.8-100% specificity for appendicitis 2
- A staged algorithm (ultrasound followed by CT if needed) achieves 99% sensitivity and 91% specificity 2
CT Findings and Management
If CT confirms appendicitis:
- Proceed to surgical consultation regardless of WBC count 1
- CT changes management in 43% of patients initially suspected to have appendicitis clinically 1
If CT excludes appendicitis:
- CT identifies the cause of RLQ pain in the majority of cases 1
- Most frequent alternative diagnoses include gynecologic conditions, gastrointestinal etiologies, genitourinary causes, vascular, and musculoskeletal causes 1
- 41% of patients with non-appendiceal diagnoses require hospitalization and 22% require surgical or image-guided intervention 1
Key Clinical Pitfalls to Avoid
- Do not discharge based solely on absence of fever and normal WBC—this risks missing early appendicitis or other serious pathology 2, 3
- Do not delay imaging if symptoms persist or worsen—NSAIDs can mask evolving symptoms and delay diagnosis 2
- Do not rely on clinical scoring alone—imaging provides definitive diagnosis and identifies alternative pathologies 1, 2
Special Considerations for Young Girls
- Gynecologic pathology must be considered as a primary differential in reproductive-age females 1
- Ovarian pathology, ectopic pregnancy (if applicable), and pelvic inflammatory disease can present identically to appendicitis 1
- Ultrasound is particularly valuable for simultaneously evaluating both appendiceal and gynecologic causes 2, 3
Follow-Up Protocol
If imaging is negative or inconclusive: