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

Management of Acute Appendicitis

For adults with suspected acute appendicitis, obtain CT abdomen and pelvis with IV contrast immediately to confirm the diagnosis, then proceed with laparoscopic appendectomy as the definitive treatment, administering broad-spectrum antibiotics covering aerobic gram-negatives and anaerobes preoperatively. 1

Initial Diagnostic Approach

Clinical Assessment and Risk Stratification

• Use clinical scoring systems to guide your diagnostic pathway—the AIR (Appendicitis Inflammatory Response) score is the best-performing tool with 92% sensitivity and 63% specificity, superior to the Alvarado score 1

• Look specifically for: characteristic periumbilical pain migrating to the right lower quadrant, localized right lower quadrant tenderness, fever, anorexia/nausea, and laboratory evidence of inflammation (elevated WBC with left shift, elevated CRP) 1, 2

• The combination of WBC >10,000/mm³ AND CRP ≥8 mg/L has a positive likelihood ratio of 23.32, making appendicitis highly likely 3

• Physical examination findings that increase likelihood: positive psoas sign, positive obturator sign, McBurney point tenderness, rebound tenderness, and guarding 1, 3

Imaging Strategy by Patient Population

For non-pregnant adults:

• CT abdomen and pelvis with IV contrast only (no oral contrast needed) is the gold standard, achieving 96-100% sensitivity and 93-95% specificity 1, 3
• IV contrast increases sensitivity to 96% compared to unenhanced CT; oral contrast is unnecessary and delays diagnosis 3
• Proceed directly to CT rather than ultrasound in adults, as this reduces negative appendectomy rates from historical 14.7% to current 1.7-7.7% 3

For children and adolescents:

• Start with ultrasound (sensitivity 76%, specificity 95%) to avoid radiation exposure 1, 3
• Point-of-care ultrasound by emergency physicians shows even higher accuracy (sensitivity 91%, specificity 97%) 3
• Key ultrasound findings: appendiceal diameter ≥7 mm, non-compressibility, appendiceal tenderness 3
• If ultrasound is non-diagnostic and clinical suspicion persists, proceed to CT or MRI 3

For pregnant patients:

• Ultrasound first; if inconclusive, use MRI without IV contrast (sensitivity 94%, specificity 96%) to avoid radiation 1, 3
• Never use CT as first-line in pregnant patients unless MRI is unavailable and clinical situation is urgent 1

For elderly patients:

• CT with IV contrast is strongly recommended due to higher rates of complicated appendicitis and mortality in this population 1, 3

Management Based on Imaging Findings

Uncomplicated Appendicitis (No perforation, abscess, or peritonitis)

Surgical management:

• Laparoscopic appendectomy is the preferred approach over open surgery, offering reduced wound infections and faster recovery 1
• Perform appendectomy within 24 hours of diagnosis for uncomplicated cases 4
• Administer prophylactic broad-spectrum antibiotics preoperatively covering aerobic gram-negatives and anaerobes (e.g., cefoxitin, cefotetan, ertapenem, or piperacillin-tazobactam) 1
• Discontinue antibiotics within 24 hours postoperatively for uncomplicated appendicitis—prolonged antibiotics are not beneficial 1

Non-operative management alternative:

• In highly selected patients with CT-confirmed uncomplicated appendicitis WITHOUT appendicolith, antibiotics-first strategy can be discussed 1, 2
• Success rate is approximately 63-73% at one year, meaning 27-37% will require appendectomy anyway 1, 2, 5
• Presence of appendicolith on CT predicts 40% failure rate of antibiotic therapy—these patients should undergo surgery 2
• Other high-risk CT findings predicting antibiotic failure: appendiceal diameter >13 mm, mass effect 2
• Antibiotic regimen: IV piperacillin-tazobactam, or cefotaxime/ceftriaxone + metronidazole, or fluoroquinolone + metronidazole for 2 days IV, then switch to oral for total 8-15 days 2, 5, 6
• This approach is NOT recommended as routine practice—appendectomy remains gold standard due to high recurrence rates and risk of antimicrobial resistance 1

Complicated Appendicitis (Perforation, gangrene, abscess, or peritonitis)

Immediate surgical intervention:

• Perform appendectomy within 8 hours for perforated appendicitis 4, 7
• Administer broad-spectrum antibiotics immediately covering mixed aerobic-anaerobic flora: acceptable regimens include aminoglycoside-based combinations, carbapenems, β-lactam/β-lactamase inhibitors, or advanced cephalosporins + metronidazole 1, 7
• Continue postoperative antibiotics for 3-5 days maximum if adequate source control achieved—longer courses provide no additional benefit 1

For large periappendiceal abscess or phlegmon:

• Consider percutaneous drainage plus antibiotics rather than immediate appendectomy 3, 8
• Interval appendectomy can be performed 6-8 weeks later, though this approach is debated 8

Special Population Considerations

Pediatric Patients

• Children under 5 years have atypical presentations with higher rates of delayed diagnosis and perforation 7
• Laparoscopic appendectomy is preferred; perform within 24 hours for uncomplicated, within 8 hours for perforated 4, 7
• Simple ligation of appendicular stump is superior to stump inversion—shorter operative time, less ileus, quicker recovery 4, 7
• Postoperative antibiotics: switch from IV to oral based on clinical improvement; total duration <7 days for complicated cases 1, 7
• Non-operative management can be discussed for uncomplicated appendicitis without appendicolith, but families must understand 27-37% recurrence risk 4

Pregnant Patients

• Proceed urgently to appendectomy to minimize maternal and fetal complications 8
• Laparoscopic approach is safe in all trimesters when performed by experienced surgeons 8

Immunosuppressed Patients

• Proceed directly to appendectomy—higher risk of rapid progression to perforation and sepsis 8

Management of Inconclusive Imaging

• If CT is negative but clinical suspicion remains high: observe for 24 hours with serial examinations and ensure follow-up 1
• If symptoms persist or worsen despite negative imaging: proceed to diagnostic laparoscopy 1
• Never discharge a patient with high clinical suspicion based solely on negative imaging—false-negative rate exists 1

Common Pitfalls to Avoid

• Do not use Alvarado score alone to confirm appendicitis—insufficient specificity, though useful for exclusion when score <5 1, 3
• Do not delay imaging in adults to "observe"—this increases perforation risk without improving diagnostic accuracy 1
• Do not order oral contrast for CT—it delays diagnosis without improving sensitivity 3
• Do not continue antibiotics beyond 24 hours for uncomplicated appendicitis after appendectomy—this is the most common error 1
• Do not attempt non-operative management if appendicolith is present on imaging—40% failure rate mandates surgery 2
• In elderly patients, do not rely on classic presentation—atypical symptoms are common and CT is essential 1, 3
• Ultrasound accuracy is highly operator-dependent; if non-diagnostic in adults, proceed directly to CT rather than repeating ultrasound 3