What is the appropriate evaluation and management of right lower quadrant pain?

Evaluation and Management of Right Lower Quadrant Pain

Initial Imaging Recommendation

For adults with right lower quadrant pain and suspected appendicitis (fever, leukocytosis), contrast-enhanced CT of the abdomen and pelvis is the imaging modality of choice, achieving sensitivities of 85.7-100% and specificities of 94.8-100%. 1

Clinical Context and Diagnostic Approach

When Appendicitis is Suspected (Variant 2: RLQ pain + fever + leukocytosis)

The classic presentation of periumbilical pain migrating to the RLQ with fever and leukocytosis occurs in only ~50% of patients, which historically led to negative appendectomy rates of 14.7%. 1 Modern imaging has dramatically reduced this to 1.7-7.7%. 1

CT Protocol Options:

• Contrast-enhanced CT without enteral contrast achieves 90-100% sensitivity and 94.8-100% specificity, avoiding delays from oral contrast administration 1
• Contrast-enhanced CT with enteral contrast (oral or rectal) shows 90.4-100% sensitivity and 97.67-100% specificity 1
• Non-enhanced CT demonstrates lower sensitivity (85.7%) but meta-analysis shows acceptable performance (90% sensitivity, 94% specificity) 1

A meta-analysis of 71 study populations confirmed CT's summary sensitivity of 0.95 (95% CI: 0.93-0.96) and specificity of 0.94 (95% CI: 0.92-0.95). 1

Critical Pitfall: Scan Both Abdomen AND Pelvis

Always image both abdomen and pelvis, not just focused pelvic imaging. In one study, 7% of patients had abnormalities outside the pelvis requiring surgery; limiting to pelvic-only imaging decreased sensitivity from 99% to 88% and missed 14% of surgical cases. 2

Alternative Diagnoses to Consider

Beyond appendicitis, RLQ pain has numerous causes that CT effectively identifies: 3, 4

• Inflammatory/infectious ileocecal conditions (Crohn's disease, infectious enterocolitis)
• Right colonic diverticulitis
• Epiploic appendagitis (look for "hyperattenuating ring sign" and "central dot sign" on CT) 5
• Gynecologic pathology (ovarian torsion, cyst rupture)
• Urinary tract pathology (nephrolithiasis, pyelonephritis) 6
• Mesenteric/omental conditions

Special Populations

Pregnant Women

MR imaging is the preferred modality for pregnant women with RLQ pain when ultrasound is inconclusive. 7 Use T2-weighted single-shot fast SE sequences, fat-suppressed T2-weighted fast SE, T1-weighted gradient-recalled-echo, and STIR sequences through lower abdomen and pelvis. 7 MR detected the appendix in 86.9% of cases and correctly identified appendicitis in 75% while also diagnosing alternative pathology like ovarian torsion. 7

Pediatric Patients

Ultrasound is the initial imaging study of choice in children due to lack of radiation exposure. 8 If ultrasound is equivocal and clinical suspicion remains high, proceed to CT with IV contrast. 8 Children under 5 years present atypically more frequently and have higher perforation rates due to delayed diagnosis. 8

Management of Complicated Appendicitis

For perforated appendicitis with abscess >3 cm, percutaneous catheter drainage (PCD) followed by delayed surgery OR PCD only with antibiotics are equivalent appropriate options. 1 This applies when CT shows thin-walled fluid collection adjacent to cecum, nonvisualized appendix, and appendicolith without peritoneal signs. 1

Diagnostic Performance Impact

Using preoperative CT versus clinical evaluation alone reduces negative appendectomy rates from 16.7% to 8.7%. 1 CT use for appendicitis diagnosis in emergency departments increased from 7.2% to 83.3% between 1997-2016, reflecting its established role. 1