What are the recommended intravenous (IV) antibiotics for appendicitis in a child less than one year old?

From the Guidelines

Intravenous antibiotics for appendicitis in infants under one year old should include a combination of ampicillin, gentamicin, and metronidazole, as this regimen provides broad-spectrum coverage against the polymicrobial nature of appendicitis, including gram-positive, gram-negative, and anaerobic bacteria. The selection of specific antimicrobial therapy for pediatric patients with complicated intra-abdominal infection, such as appendicitis, should be based on considerations of the origin of infection, severity of illness, and safety of the antimicrobial agents in specific pediatric age groups 1. According to the guidelines, acceptable broad-spectrum antimicrobial regimens for pediatric patients with complicated intra-abdominal infection include an aminoglycoside-based regimen, a carbapenem, a β-lactam/β-lactamase–inhibitor combination, or an advanced-generation cephalosporin with metronidazole 1.

For infants under one year old, the regimen of ampicillin, gentamicin, and metronidazole is recommended, as it is effective against the common pathogens involved in appendicitis, including E. coli and Bacteroides spp. 1. The dosage of these antibiotics should be adjusted based on the infant's weight, with ampicillin at 50 mg/kg every 6 hours, gentamicin at 2.5 mg/kg every 8 hours, and metronidazole at 10 mg/kg every 8 hours.

It is also important to note that the treatment duration depends on the disease severity, with 24-48 hours for simple appendicitis following appendectomy, or 7-10 days for complicated cases with perforation or abscess formation 1. Infants require careful monitoring of fluid status, electrolytes, and renal function during therapy, with dose adjustments based on weight. Prompt surgical consultation is essential alongside antibiotic therapy, as most cases will require appendectomy after initial stabilization.

The use of broad-spectrum antibiotics in infants under one year old with appendicitis is supported by recent guidelines, which recommend the routine use of a combination of clinical scores and imaging studies, such as ultrasound or CT scan, to diagnose and manage acute appendicitis 1. The guidelines also emphasize the importance of considering the epidemiology of bacteria and the severity of illness when selecting antimicrobial therapy.

In summary, the recommended regimen of ampicillin, gentamicin, and metronidazole provides effective broad-spectrum coverage against the polymicrobial nature of appendicitis in infants under one year old, and should be adjusted based on the infant's weight and disease severity, with careful monitoring and prompt surgical consultation as needed.

From the Research

IV Antibiotics for Appendicitis in Children Under One Year

• The provided studies do not specifically address the use of IV antibiotics for appendicitis in children under one year old.
• However, some studies discuss the use of antibiotics in children with appendicitis, such as the study by 2, which evaluated the impact of a switch from a combination of cefotaxime, metronidazole, and gentamicin to piperacillin/tazobactam as first-line regimen for complicated acute appendicitis in children.
• Another study by 3 reported excellent outcomes using a standard protocol to treat pediatric appendicitis, which included preoperative gentamicin and clindamycin, and postoperative ampicillin, gentamicin, and clindamycin or metronidazole for complicated cases.
• A more recent study by 4 determined the optimal first-line antibiotic treatment for pediatric patients with complicated appendicitis based on peritoneal fluid cultures, and found that tazobactam/piperacillin or meropenem is a reasonable first-line antibiotic treatment.
• It is essential to note that these studies may not be directly applicable to children under one year old, and more specific research is needed to provide evidence-based guidance for this age group.

Antibiotic Regimens

• The study by 2 compared two antibiotic regimens: cefotaxime, metronidazole, and gentamicin (regimen 1) and piperacillin/tazobactam (regimen 2), and found that regimen 2 was associated with reduced protocol deviation and duration of antibiotics.
• The study by 4 found that tazobactam/piperacillin and meropenem inhibited the growth of 96.9-100% of the major identified bacteria in peritoneal fluid cultures of pediatric patients with complicated appendicitis.
• The study by 3 used a combination of gentamicin, clindamycin, ampicillin, and metronidazole for the treatment of pediatric appendicitis.

Limitations

• The provided studies have limitations, such as the study by 2, which had a median age of 10 years, and may not be directly applicable to children under one year old.
• The study by 3 was conducted over 20 years ago, and may not reflect current practices or antibiotic resistance patterns.
• More research is needed to provide evidence-based guidance for the use of IV antibiotics in children under one year old with appendicitis, as stated by 5, 6.