What is the assessment and management plan for a patient presenting with suspected appendicitis in an acute setting?

Assessment and Management of Acute Appendicitis in the Emergency Department

Initial Clinical Assessment

Use clinical findings systematically to risk-stratify patients with suspected appendicitis, combining specific symptoms, physical examination signs, and laboratory tests to guide decisions about imaging and surgical consultation. 1

Key Clinical Features to Document

• Classic symptom progression: Vague periumbilical pain that migrates to the right lower quadrant is highly suggestive of appendicitis 2, 3
• Associated symptoms: Anorexia, nausea, intermittent vomiting, and low-grade fever 2
• Critical physical examination findings:
  • Right lower quadrant tenderness (McBurney point)
  • Rebound tenderness and guarding 3
  • Psoas sign (pain with hip extension) 3
  • Obturator sign (pain with internal hip rotation) 3
  • Rovsing sign (right lower quadrant pain with left lower quadrant palpation) 3

Risk Stratification Using Clinical Scoring Systems

Apply validated clinical scoring systems to stratify risk before proceeding with imaging. 3, 4

• For adults: Use the AIR (Appendicitis Inflammatory Response) score or AAS (Adult Appendicitis Score) as these demonstrate the highest discriminating power 3
• For children: Use the Pediatric Appendicitis Score or Alvarado score to help exclude appendicitis, but never make the diagnosis based on clinical scores alone 3
• Important caveat: The Alvarado score should NOT be used alone to confirm appendicitis in adults due to insufficient specificity, though it helps exclude the diagnosis 3

Laboratory Evaluation

Obtain WBC with differential and CRP in all patients with suspected appendicitis. 3, 4

Interpretation of Laboratory Results

• WBC >10,000/mm³ alone has limited diagnostic value (positive likelihood ratio only 1.59-2.7) 1, 3
• CRP ≥10 mg/L has a positive likelihood ratio of 4.24 3
• Combined WBC >10,000/mm³ AND CRP ≥8 mg/L is most powerful with a positive likelihood ratio of 23.32 and negative likelihood ratio of 0.03 3
• WBC with left shift combined with elevated total WBC has a positive likelihood ratio of 9.8 3, 4

Imaging Strategy Based on Patient Population

Adults (Non-Pregnant)

CT abdomen and pelvis with IV contrast is the primary imaging modality for non-pregnant adults with intermediate-to-high clinical suspicion. 3, 4

• Diagnostic accuracy: Sensitivity 96-100%, specificity 93-95% 1, 3
• IV contrast is strongly preferred as it increases sensitivity to 96% compared to unenhanced CT 3
• Oral contrast is NOT necessary and may delay diagnosis—IV contrast alone provides excellent diagnostic accuracy 3
• Rectal contrast achieves similar accuracy (sensitivity 93-98%, specificity 95-98%) but may be uncomfortable 1

Children and Adolescents

Ultrasound is the recommended initial imaging modality in children to avoid radiation exposure. 1, 3

• Diagnostic accuracy: Sensitivity 76-99%, specificity 88-98% 1
• Key ultrasound findings: Appendiceal diameter ≥7 mm, non-compressibility, and appendiceal tenderness 3
• Point-of-care ultrasound (POCUS) performed by emergency physicians or surgeons shows higher accuracy (sensitivity 91%, specificity 97%) 3, 4
• If ultrasound is inconclusive: Proceed to CT abdomen/pelvis with IV contrast or consider MRI 1, 3

Pregnant Patients

Ultrasound is the initial imaging modality for pregnant patients. 3

• If ultrasound is inconclusive: MRI without IV contrast is preferred over CT to avoid radiation exposure 3
• MRI diagnostic accuracy: Sensitivity 94%, specificity 96% 3

Elderly Patients

CT scan with IV contrast is strongly recommended in elderly patients due to higher rates of complicated appendicitis and mortality. 3

Management Algorithm Based on Risk Stratification

Very Low Clinical Suspicion

• Discharge with minimal or no testing 3
• Ensure 24-hour follow-up 3

Intermediate Clinical Suspicion

• Adults: Obtain CT abdomen/pelvis with IV contrast 3, 4
• Children: Obtain ultrasound first; if inconclusive, proceed to CT or MRI 3
• Pregnant patients: Obtain ultrasound first; if inconclusive, proceed to MRI 3

High Clinical Suspicion

• Refer directly to surgeon with minimal or no testing 3
• Initiate broad-spectrum antibiotics immediately covering aerobic gram-negative organisms and anaerobes 4, 2
• Recommended antibiotic regimens: Piperacillin-tazobactam monotherapy OR combination therapy with cephalosporins or fluoroquinolones plus metronidazole 2

Surgical Management

Appendectomy should be performed as soon as reasonably feasible once diagnosis is established. 4

• Both laparoscopic and open appendectomy are acceptable, with laparoscopic approach preferred in children 4
• For complicated appendicitis with large periappendiceal abscess or phlegmon: Consider percutaneous drainage rather than immediate appendectomy 3

Non-Operative Management Consideration

In highly selected patients with uncomplicated appendicitis and absence of appendicolith on imaging, an antibiotics-first strategy can be discussed as an alternative to surgery. 4

• Success rate: Approximately 63-73% at one year 2
• High-risk CT findings predicting antibiotic failure (≈40% failure rate): Appendicolith, mass effect, or dilated appendix >13 mm 2
• Surgical management should be recommended in patients with these high-risk CT findings who are fit for surgery 2

Critical Pitfalls to Avoid

• Do NOT administer analgesics before completing diagnostic evaluation, as this may mask peritoneal signs 5
• Do NOT rely solely on clinical findings without appropriate imaging in intermediate-risk patients, as this can lead to missed diagnoses 5
• Do NOT assume absence of peritoneal signs excludes appendicitis, especially in atypical presentations 5
• Ultrasound accuracy is highly operator-dependent, and both MRI and ultrasound may incorrectly classify up to half of patients with perforated appendicitis as having simple appendicitis 3
• Low or incomplete Alvarado scores do not reliably exclude appendicitis—studies show 8.4% of patients with appendicitis had Alvarado scores below 5 3
• In elderly patients, atypical presentations are common, making clinical diagnosis alone unreliable 3

Management After Inconclusive Imaging

If imaging is negative but clinical suspicion remains high: 3

• Consider observation and supportive care with or without antibiotics
• Surgical intervention if clinical suspicion is very high despite negative imaging
• Follow-up within 24 hours if discharged