What is the management of acute appendicitis in the emergency department?

Emergency Department Management of Acute Appendicitis

The primary management of acute appendicitis in the emergency department involves prompt diagnosis using CT imaging in adults (ultrasound first in children and pregnant women), initiation of broad-spectrum intravenous antibiotics, and urgent surgical consultation for appendectomy, which remains the definitive treatment for most patients. 1, 2

Initial Assessment and Diagnosis

Clinical Evaluation

• Look for the classic triad: periumbilical pain migrating to the right lower quadrant, fever, and right lower quadrant tenderness 1
• Key physical exam findings that increase likelihood of appendicitis include positive psoas sign, fever, and migratory pain to the right lower quadrant 1
• Red flags: vomiting before pain onset makes appendicitis less likely 1
• High-risk populations require heightened vigilance: elderly patients (>65 years) have perforation rates of 18-70% versus 3-29% in younger patients, with mortality reaching 8% 3

Imaging Strategy

• Adults: CT scan is the preferred imaging modality with sensitivity 88-97% and specificity 90-100% 1, 2
• Children: Start with ultrasound to avoid radiation exposure; if inconclusive, proceed to CT or MRI 1, 4
• Pregnant women (first trimester): Ultrasound first-line; MRI (not CT) if ultrasound is inconclusive with 94% sensitivity and 96% specificity 1, 2
• Follow-up protocol: Patients with negative imaging but persistent clinical suspicion should be reassessed at 24 hours 2

Immediate ED Management

Antibiotic Therapy

All patients diagnosed with appendicitis should receive antibiotics immediately in the ED, regardless of whether surgery or non-operative management is planned. 2

Recommended empiric antibiotic regimens for community-acquired appendicitis 2:

• First-line: Amoxicillin/clavulanate 1.2-2.2g IV every 6 hours, OR
• Alternative: Ceftriaxone 2g IV daily + metronidazole 500mg IV every 6 hours, OR
• Alternative: Cefotaxime 2g IV every 8 hours + metronidazole 500mg IV every 6 hours
• Beta-lactam allergy: Ciprofloxacin 400mg IV every 8 hours + metronidazole 500mg IV every 6 hours, OR Moxifloxacin 400mg IV daily

For complicated appendicitis (perforation/abscess): Piperacillin-tazobactam 3.375g IV every 6 hours is FDA-approved for appendicitis complicated by rupture or abscess 5

Surgical Consultation and Timing

• Uncomplicated appendicitis: Surgery should be performed within 24 hours of admission 4
• Complicated appendicitis: Early appendectomy within 8 hours is recommended 4
• Critical caveat: Delaying surgery by 10-15 hours to accommodate scheduling does not significantly increase morbidity in stable patients, but this should not be routine practice 6

Disposition Decisions

Candidates for Surgical Management (Majority of Patients)

Laparoscopic appendectomy is the preferred surgical approach with better outcomes than open surgery 4

Immediate surgical intervention is indicated for 1, 2:

• Complicated appendicitis (perforation, diffuse peritonitis)
• Hemodynamic instability
• Pregnant patients (to reduce complication risk)
• Immunosuppressed patients
• Presence of appendicolith (strongly associated with progression to complicated disease) 3

Selected Candidates for Non-Operative Management

Non-operative management (NOM) with antibiotics alone can be discussed as an alternative in highly selected patients with uncomplicated appendicitis 2

Strict criteria for NOM consideration 2:

• CT-confirmed uncomplicated appendicitis
• Absence of appendicolith (critical exclusion criterion)
• Marked clinical improvement within 24 hours of antibiotic therapy
• Patient willingness to accept 27% recurrence rate at 1 year
• Ability to comply with close follow-up

NOM protocol if selected 2:

• Hospitalize for minimum 48 hours observation
• IV antibiotics for at least 48 hours, then oral antibiotics for total 7-10 days
• Monitor for fever resolution, pain improvement, and laboratory normalization
• Success rate approximately 70-80% at 1 year, but only 68.4% remain complication-free versus 89.8% with surgery 7

Important caveat: Patients and families must be counseled about treatment failure risk and possibility of misdiagnosing complicated appendicitis 4, 2

Management of Appendiceal Abscess/Phlegmon

For well-circumscribed periappendiceal abscess 1, 2:

• Non-operative management with IV antibiotics is reasonable first-line treatment
• Add percutaneous drainage if abscess is accessible and >3-4 cm
• Laparoscopic surgery is preferred if advanced laparoscopic expertise is available, as it reduces readmissions and additional interventions 1
• Do NOT perform routine interval appendectomy in young adults (<40 years) and children after successful NOM 1
• Exception: Interval appendectomy IS recommended for patients ≥40 years old due to 3-17% incidence of appendiceal neoplasms; perform colonoscopy and contrast-enhanced CT for screening 1

Critical Pitfalls to Avoid

• Elderly patients: Do not underestimate disease severity—they present with atypical symptoms, have higher perforation rates, and require aggressive early intervention 3
• Delayed diagnosis: The median time from symptom onset to care in complicated cases is 4 days; do not discharge patients with equivocal findings without close follow-up 3
• Misclassifying complicated as uncomplicated: This leads to NOM failure and increased morbidity; when in doubt, choose surgery 2
• Ignoring appendicolith on imaging: This is a strong predictor of complicated disease and contraindication to NOM 3, 2
• Inadequate antibiotic coverage: Must cover gram-negatives and anaerobes (E. coli and Bacteroides fragilis group) 5