Management of Right Lower Quadrant Rebound Tenderness
Obtain CT abdomen and pelvis with IV contrast as the primary diagnostic imaging study, as this achieves 95% sensitivity and 94% specificity for appendicitis while identifying alternative diagnoses in 23-45% of cases. 1, 2
Immediate Clinical Actions
- Establish NPO status, initiate IV fluid resuscitation, and start broad-spectrum antibiotics while awaiting imaging 2
- Obtain surgical consultation urgently, as rebound tenderness is a highly specific physical finding associated with peritoneal irritation requiring operative intervention 1
- Check complete blood count with differential (absolute neutrophil count >6,750/mm³ significantly associated with appendicitis), C-reactive protein, and urinalysis 1
Diagnostic Imaging Algorithm
CT abdomen/pelvis with IV contrast is the first-line imaging modality for the following reasons:
- Provides definitive diagnosis with 95% sensitivity and 94% specificity for appendicitis 1, 2
- Identifies critical alternative diagnoses including right-sided colonic diverticulitis (8% of RLQ pain cases), bowel obstruction (3%), colorectal malignancy, mesenteric ischemia, and gynecologic pathology 1, 3
- IV contrast is essential for optimal diagnostic accuracy, highlighting appendiceal wall inflammation and periappendiceal changes 1
- Oral contrast may be added for better bowel visualization but is not mandatory 1, 2
When Ultrasound May Be Considered First
- Pediatric patients: Ultrasound is the initial imaging of choice due to zero radiation exposure, with reasonable sensitivity for appendicitis and ability to identify intussusception 4
- Women of reproductive age: Combined transabdominal and transvaginal ultrasound achieves 97.3% sensitivity and 91% specificity for gynecologic causes, but equivocal results require CT anyway 2
- Critical limitation: Appendix not visualized in 20-81% of ultrasound cases, creating diagnostic uncertainty that necessitates CT 2
Management Based on Imaging Results
If Appendicitis Confirmed
- Proceed to appendectomy as standard treatment 4, 5
- For perforated appendicitis with abscess: percutaneous drainage followed by interval appendectomy with broad-spectrum antibiotics 4, 5
If Alternative Diagnosis Identified
- Right-sided colonic diverticulitis: Antibiotics with possible surgical intervention if complicated 1, 3
- Bowel obstruction: Nasogastric decompression, surgical consultation for adhesive or malignant obstruction 2
- Psoas abscess (especially if associated with hip flexion weakness): Immediate broad-spectrum antibiotics and percutaneous drainage for collections >3 cm 5
Critical Clinical Pitfalls
Do not exclude appendicitis based on normal laboratory values alone. In a study of 326 patients with confirmed appendicitis, 15.6% presented with isolated rebound tenderness without fever, elevated white blood cell count, or elevated C-reactive protein 6. Imaging confirmed appendicitis in 96.1% of these atypical cases 6.
Rebound tenderness has the highest positive predictive value (65%) among clinical findings for predicting complicated appendicitis in pediatric patients, outperforming fever, migration of pain, and leukocytosis 1.
Special Population Considerations
Elderly Patients
- Atypical presentations are the norm, with blunted inflammatory responses and higher perforation rates due to delayed diagnosis 2
- CT with IV contrast is mandatory as first-line imaging—do not attempt ultrasound first 2
- Consider broader differential including colorectal malignancy (60% of large bowel obstructions in elderly), diverticulitis, and mesenteric ischemia 2
Pediatric Patients
- Children under 5 years have higher perforation rates and more atypical presentations 4
- Ultrasound first, followed by MRI (not CT) if equivocal, to minimize radiation exposure 4
- Consider intussusception, mesenteric adenitis, and constipation in differential 4