What IV antibiotics to start in the Emergency Department (ED) for an 11-year-old patient with appendicitis and microperforation?

From the Guidelines

For an 11-year-old patient with appendicitis and microperforation in the Emergency Department, I recommend starting empiric IV antibiotic therapy with a combination of piperacillin-tazobactam (100 mg/kg/dose of the piperacillin component every 8 hours, maximum 4 g piperacillin per dose) or ceftriaxone (50 mg/kg/day once daily, maximum 2 g) plus metronidazole (10 mg/kg/dose every 8 hours, maximum 500 mg per dose). Alternatively, a single agent like ertapenem (15 mg/kg twice daily, maximum 1 g per day) can be used. These recommendations are based on the most recent guidelines for the diagnosis and treatment of acute appendicitis, which emphasize the importance of broad-spectrum antibiotic coverage for patients with complicated appendicitis, including those with microperforation 1. The goal of antibiotic therapy is to cover common pathogens involved in intra-abdominal infections, including gram-negative enteric bacteria (E. coli, Klebsiella) and anaerobes (Bacteroides fragilis). Microperforation indicates contamination of the peritoneal cavity with intestinal contents, requiring broad-spectrum coverage to prevent progression to peritonitis and sepsis. Antibiotics should be administered through a reliable IV access with appropriate infusion times (typically 30 minutes for ceftriaxone and metronidazole, and 30-60 minutes for piperacillin-tazobactam). Ensure the patient's weight is accurately measured for precise dosing, and monitor for any signs of allergic reactions during administration. Some key points to consider when selecting antibiotics include:

• The use of extended-spectrum antibiotics may not offer any advantage over narrower-spectrum agents for children with acute appendicitis 1
• The importance of considering local microbiologic data, cost, allergies, and formulary availability when selecting antibiotics 1
• The need for broad-spectrum coverage, including activity against enteric gram-negative organisms and anaerobes, in patients with complicated appendicitis 1

From the FDA Drug Label

The recommended dosage for pediatric patients with appendicitis and/or peritonitis or nosocomial pneumonia aged 2 months of age and older, weighing up to 40 kg, and with normal renal function, is described in Table 2 Table 2: Recommended Dosage of Piperacillin and Tazobactam for Injection in Pediatric Patients 2 Months of Age and Older, Weighing up to 40 kg, and with Normal Renal Function

Age	Appendicitis and/or Peritonitis	Nosocomial Pneumonia
2 months to 9 months	90 mg/kg (80 mg piperacillin and 10 mg tazobactam) every 8 hours	90 mg/kg (80 mg piperacillin and 10 mg tazobactam) every 6 hours
Older than 9 months of age	112.5 mg/kg (100 mg piperacillin and 12.5 mg tazobactam) every 8 hours	112.5 mg/kg (100 mg piperacillin and 12.5 mg tazobactam) every 6 hours

For an 11-year-old patient with appendicitis and microperforation, since the patient is older than 9 months and the exact weight is not provided, but assuming the patient weighs up to 40 kg, the recommended dosage would be 112.5 mg/kg (100 mg piperacillin and 12.5 mg tazobactam) every 8 hours. However, if the patient weighs over 40 kg, the adult dose should be considered, which is 3.375 grams every 6 hours for appendicitis and/or peritonitis. Given the patient's age and condition, piperacillin-tazobactam is an appropriate choice for IV antibiotics in the ED, with the dosage dependent on the patient's weight 2.

From the Research

IV Antibiotics for Appendicitis and Microperforation in an 11-Year-Old

• The choice of IV antibiotics for an 11-year-old patient with appendicitis and microperforation can be guided by several studies 3, 4, 5, 6, 7.
• A prospective randomized trial compared the efficacy and cost-effectiveness of ceftriaxone and metronidazole (CM) versus a standard triple antibiotic regimen (ampicillin, gentamicin, and clindamycin) for perforated appendicitis in children, finding that CM was a more simple and cost-effective strategy without compromising infection control 3.
• Another study compared ceftriaxone plus metronidazole (CTX/MTZ) with anti-pseudomonal antibiotics for perforated appendicitis in children, concluding that post-operative complication rates did not differ significantly between the two groups 4.
• A review of perforated appendicitis in children discussed the benefits of mono- versus dual or triple therapy, highlighting the need for minimization of care variability for improved patient outcomes and proper antibiotic stewardship 5.
• An intervention to reduce piperacillin and tazobactam (PT) use for pediatric perforated appendicitis was found to be effective and safe, with no significant difference in clinical outcomes between the preintervention and postintervention groups 6.
• A comparative trial of four antibiotic combinations for perforated appendicitis in children found that all regimens had the same clinical and bacteriological efficacy, suggesting that different antibiotic combinations or a single broad-spectrum antibiotic can be used safely in children with perforated appendicitis 7.

Recommended Antibiotic Regimens

• Ceftriaxone and metronidazole (CM) is a recommended regimen for perforated appendicitis in children, given its simplicity, cost-effectiveness, and equivalent efficacy to standard triple antibiotic regimens 3, 4.
• Anti-pseudomonal antibiotics may be considered as an alternative, although their use did not result in significantly different post-operative complication rates compared to CM 4.
• Piperacillin and tazobactam (PT) can be reduced or avoided in favor of CM, as an intervention to decrease PT use was found to be effective and safe 6.