What is the recommended treatment for a patient suspected of having appendicitis?

Treatment of Suspected Appendicitis

Immediate Management

Appendectomy remains the standard of care for acute appendicitis and should be performed as soon as reasonably feasible once diagnosis is established, with broad-spectrum antibiotics administered immediately upon diagnosis or strong suspicion. 1

Diagnostic Confirmation

• Obtain CT abdomen and pelvis with IV contrast immediately in non-pregnant adults with suspected appendicitis, achieving sensitivity of 96-100% and specificity of 93-95%. 1, 2
• IV contrast alone is sufficient and strongly preferred—oral contrast is unnecessary and delays diagnosis. 2
• For children and adolescents, ultrasound is the first-line imaging modality (sensitivity 76%, specificity 95%) to avoid radiation exposure. 1, 2
• For pregnant patients, use ultrasound first, followed by MRI without IV contrast if inconclusive (sensitivity 94%, specificity 96%). 1, 2

Antibiotic Therapy

Initiate broad-spectrum antibiotics immediately once appendicitis is diagnosed or strongly suspected, covering both aerobic gram-negative organisms and anaerobes. 1

Recommended Regimens

• Piperacillin-tazobactam 3.375 grams IV every 6 hours (totaling 13.5 grams daily) for uncomplicated appendicitis, administered over 30 minutes for 7-10 days. 3
• Alternative regimens include combination therapy with cephalosporins or fluoroquinolones plus metronidazole. 4
• For complicated appendicitis with rupture or abscess, piperacillin-tazobactam is FDA-approved and covers beta-lactamase producing E. coli and Bacteroides fragilis group organisms. 3

Surgical Intervention

Operative intervention should be performed as soon as reasonably feasible—both laparoscopic and open appendectomy are acceptable, with the approach dictated by surgeon expertise. 1

• For uncomplicated appendicitis, surgery should be performed within 24 hours of admission. 1
• For complicated appendicitis (perforation, peritonitis), early appendectomy within 8 hours is recommended. 1
• Laparoscopic appendectomy is the preferred approach for children with acute appendicitis. 1
• Delaying surgery beyond 10 hours after diagnosis does not significantly increase complications, operative time, or length of stay, allowing reasonable scheduling flexibility. 5

Special Considerations for Complicated Appendicitis

• Patients with perforated appendicitis require urgent intervention for adequate source control. 1
• Large periappendiceal abscess or phlegmon may warrant percutaneous drainage combined with antibiotics rather than immediate appendectomy. 6, 7
• Pregnant and immunosuppressed patients should undergo timely surgical intervention to decrease risk of complications. 7

Non-Operative Management (Highly Selected Cases Only)

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, but success rates are only 63-73% at one year. 6, 4, 8

Criteria for Considering Antibiotics-First Approach

• Uncomplicated appendicitis without high-risk CT findings (no appendicolith, no mass effect, appendiceal diameter <13 mm). 4
• Patients unfit for surgery with relatively high perioperative risk. 4
• Patient preference after informed discussion of risks. 9

Contraindications to Antibiotics-First Approach

• Presence of appendicolith on CT—associated with approximately 40% treatment failure rate. 4
• Mass effect or dilated appendix >13 mm on imaging. 4
• Complicated appendicitis (perforation, abscess, peritonitis). 1
• Pregnant or immunosuppressed patients. 7

Outcomes of Antibiotic Treatment

• Approximately 30.7% of antibiotic-treated patients require appendectomy within one year, meaning two-thirds avoid surgery. 8
• Success of treatment at one year is 73% with antibiotics versus 97% with immediate appendectomy. 9
• Antibiotics may reduce wound infections (RR 0.25) but increase negative appendectomy rates if surgery becomes necessary later (RR 3.16). 8

Critical Pitfalls to Avoid

• Never proceed directly to surgery without imaging in patients with incomplete clinical findings—this risks unnecessary surgery and missing alternative diagnoses. 2
• Never delay antibiotics in confirmed or strongly suspected cases—this increases risk of complications. 1
• Never rely solely on clinical findings without appropriate imaging—this leads to missed diagnoses or unnecessary surgeries. 1
• Routine histopathology after appendectomy is recommended to identify unexpected findings, including rare malignancies (0.3% incidence). 1, 6
• For patients with negative imaging but persistent clinical suspicion, ensure 24-hour follow-up due to low but measurable false-negative rates. 6