What should be done for a patient experiencing severe and persistent right lower quadrant pain, possibly accompanied by fever, nausea, or vomiting?

Right Lower Quadrant Pain: Diagnostic and Management Approach

Immediate Action

Obtain a contrast-enhanced CT scan of the abdomen and pelvis immediately as the primary diagnostic test, which achieves 85.7-100% sensitivity and 94.8-100% specificity for identifying appendicitis and alternative pathologies. 1, 2, 3

Clinical Assessment

Key Historical Features to Elicit

• Migratory pain pattern: Ask specifically if pain began periumbilically or epigastrically and then migrated to the right lower quadrant, which is the classic presentation of acute appendicitis 2, 4
• Associated symptoms: Document presence of anorexia, nausea, vomiting, and fever—this combination strongly suggests appendicitis 2, 4
• Back pain component: If present, this may indicate retroperitoneal irritation from a retrocecal appendix 2
• Timing and aggravating factors: Recent heavy lifting suggests possible psoas muscle injury; recent meat consumption raises concern for infectious enterocolitis 3

Critical Physical Examination Findings

• Psoas sign: Test for pain with hip extension or flexion, which suggests appendicitis or retroperitoneal pathology 2, 3
• Rebound tenderness and guarding: These peritoneal signs significantly increase likelihood of appendicitis and may indicate need for urgent surgery 1, 5
• Right lower quadrant tenderness: Present in most cases but not specific 1

Important caveat: In elderly patients, do not rely on clinical signs and symptoms alone, as typical presentations occur in less than 50% of cases, and many present with signs of bowel obstruction or ileus rather than classic appendicitis symptoms 1

Laboratory Testing

Order the following immediately:

• C-reactive protein (CRP): Significantly elevated in appendicitis; normal CRP combined with normal white blood cell count has 100% negative predictive value for excluding appendicitis 1, 2, 3
• Complete blood count with differential: Elevated white blood cell count and neutrophil percentage support appendicitis diagnosis 1, 5
• Basic metabolic panel: Assess for dehydration and electrolyte abnormalities if vomiting is present 3

Imaging Strategy

Primary Imaging Modality

CT abdomen/pelvis with IV contrast (without oral/enteral contrast) is the definitive test 1, 2, 3, 4

• Provides 90-100% sensitivity and 94.8-100% specificity 1, 2, 3
• Avoids delays associated with oral contrast administration, which can increase perforation risk 3, 4
• Identifies alternative diagnoses including psoas abscess, mesenteric adenitis, diverticulitis, infectious colitis, and epiploic appendagitis 3, 6, 7

Alternative Imaging Considerations

• Ultrasound with graded compression: May be appropriate as initial test in children, pregnant women, or when avoiding radiation is priority, though sensitivity is lower (51.8-81.7%) 1, 4
• MRI: Consider in pregnant patients when ultrasound is inconclusive (96% sensitivity and specificity) 4

Do not delay CT imaging for oral contrast preparation, as this increases time to diagnosis without improving accuracy 3, 4

Differential Diagnosis Beyond Appendicitis

The CT scan will evaluate for:

• Epiploic appendagitis: Look for hyperdense rim sign and central dot sign on CT 7
• Psoas muscle strain or abscess: Especially if history of heavy lifting 3
• Infectious enterocolitis: Consider if recent meat consumption 3
• Diverticulitis: Though more common in left lower quadrant, right-sided colonic diverticula occur 1, 6
• Gynecologic pathology: Ovarian cyst, pelvic inflammatory disease, ectopic pregnancy in women 5, 8
• Mesenteric adenitis: More common in children 6, 5

Management Algorithm

If CT Confirms Appendicitis

• Proceed directly to appendectomy as standard treatment 2, 3
• If perforated appendicitis with abscess: Consider percutaneous drainage followed by interval appendectomy 2, 3

If CT is Negative but Clinical Suspicion Remains High

• Diagnostic laparoscopy has both diagnostic and therapeutic value 2
• Active observation with serial physical examinations is safe in patients without peritoneal signs 5

Supportive Care During Evaluation

• IV fluid resuscitation for dehydration from vomiting 2
• Antiemetics: Dopamine antagonists (metoclopramide, prochlorperazine) or serotonin antagonists for nausea control 2
• NPO status until surgical decision is made

Critical Pitfalls to Avoid

• Do not rely on clinical scoring systems (Alvarado score) alone for diagnosis, particularly in elderly patients or those with atypical presentations—they are useful for excluding appendicitis in low-risk patients but not for confirming it 1, 3
• Do not dismiss the diagnosis in elderly patients with atypical presentations, as they have higher rates of perforation due to delayed diagnosis and may present with signs of obstruction rather than classic symptoms 1
• Do not assume appendicitis is the only diagnosis—maintain broad differential and let CT imaging guide definitive diagnosis 6, 8
• Do not perform colonoscopy acutely—if diverticulitis or other inflammatory condition is found, delay colonoscopy 6-8 weeks until complete symptom resolution 1