What is the evaluation and workup for right lower quadrant pain?

Evaluation and Workup for Right Lower Quadrant Pain

Computed tomography (CT) of the abdomen and pelvis with contrast media is the initial imaging study of choice for evaluating patients with right lower quadrant pain due to its high diagnostic accuracy for appendicitis and ability to identify alternative diagnoses. 1

Initial Clinical Assessment

• Key history elements to focus on:

  • Pain characteristics (onset, duration, migration, severity)
  • Associated symptoms (fever, nausea, vomiting, anorexia)
  • Menstrual history and pregnancy status in women
  • Previous similar episodes
  • Recent gastrointestinal illness

• Physical examination findings to document:

  • Vital signs (particularly fever)
  • Abdominal tenderness location and severity
  • Presence of rebound tenderness or guarding
  • McBurney's point tenderness (suggests appendicitis)
  • Rovsing's sign (pain in RLQ when LLQ is palpated)
  • Psoas sign (RLQ pain with hip extension)
  • Obturator sign (RLQ pain with internal rotation of flexed right thigh)

Laboratory Evaluation

• Complete blood count (look for leukocytosis)
• C-reactive protein (elevated in inflammatory conditions)
• Urinalysis (to rule out UTI or nephrolithiasis)
• Beta-hCG in all women of reproductive age (critical before imaging) 1
• Liver function tests if hepatobiliary pathology suspected

Imaging Algorithm

1. CT abdomen and pelvis with IV contrast

   • Highest diagnostic accuracy for appendicitis (sensitivity 95%, specificity 94%) 1
   • Excellent for identifying alternative diagnoses 1
   • Provides information about disease extent and complications
   • Can guide surgical planning

2. Ultrasonography (alternative in select populations)

   • Consider in pregnant patients, children, or when radiation exposure is a concern
   • Moderate performance for appendicitis diagnosis
   • Limited by operator dependence and patient factors (obesity)
   • May require follow-up CT if findings are equivocal or appendix not visualized

3. MRI (specialized situations)

   • Consider in pregnant patients when ultrasound is inconclusive
   • High sensitivity (96%) and specificity (96%) for appendicitis 1
   • Limited availability in emergency settings
   • Longer acquisition time than CT

Common Diagnoses to Consider

• Appendicitis (most common surgical cause)
• Ileocecal conditions (Crohn's disease, infectious ileocolitis)
• Right-sided diverticulitis
• Gynecologic conditions (ovarian torsion, ectopic pregnancy, PID)
• Urologic conditions (nephrolithiasis, pyelonephritis)
• Mesenteric adenitis
• Cecal or appendiceal malignancy
• Epiploic appendagitis
• Omental infarction

Important Pitfalls to Avoid

1. Failing to obtain pregnancy testing before radiation exposure in women of reproductive age
2. Relying solely on conventional radiography, which has limited diagnostic value 1
3. Delaying imaging in patients with concerning clinical features (fever, significant tenderness, leukocytosis)
4. Missing alternative diagnoses by focusing only on appendicitis
5. Performing focused pelvic-only CT, which can miss important abdominal pathology (sensitivity decreases from 99% to 88%) 2

Special Considerations

• Pregnant patients: Ultrasound first, followed by MRI if inconclusive
• Children: Consider ultrasound as initial imaging modality
• Elderly patients: Lower threshold for CT due to atypical presentations and higher risk of complications
• Immunocompromised patients: Broader differential and higher risk of complications

CT with IV contrast remains the gold standard for evaluating right lower quadrant pain due to its superior diagnostic performance and ability to identify the wide range of potential causes beyond appendicitis 1, 3. While radiation exposure is a concern, the benefit of accurate diagnosis typically outweighs this risk in patients with significant clinical concern for appendicitis or other acute pathology.