Clinical context (Bacterial peritonitis without surgically demonstrable intra-abdominal source — usually spontaneous bacterial peritonitis (SBP) in ascites from nephrotic syndrome or chronic liver disease; rare primary cases in previously healthy young children)
First-line therapy
Cefotaxime • i.v. • 50–50 mg/kg/dose • 3×/day
Max 2000 mg/dose · Max 6000 mg/day · Duration: 7–10 days · Preferred when ceftriaxone biliary sludging concern or neonatal/infant dosing flexibility needed
Max 2000 mg/dose · Duration: 7–10 days · Alternative empiric regimen per pediatric nephrotic/SBP literature — monitor gentamicin levels if therapy prolonged
• Ampicillin + gentamicin: alternative empiric regimen cited in pediatric SBP/nephrotic syndrome guidelines (Nelson, SSNS Table 5) — covers pneumococcus and enteric Gram-negatives.
• Add vancomycin if concern for penicillin-resistant Streptococcus pneumoniae or high local pneumococcal resistance — tailor to culture and susceptibility (SSNS, IDSA principles).
• Oral step-down when improving: amoxicillin, amoxicillin/clavulanate, or cephalexin/cefixime per isolate sensitivities — switch after 48–72 h IV if afebrile and tolerating oral intake.
• Piperacillin/tazobactam is not recommended for typical primary/SBP — anaerobic and broad intra-abdominal coverage is unnecessary; use only if secondary peritonitis cannot be excluded (see secondary peritonitis card; SIS, WSES).
• CAPD-associated peritonitis requires separate intraperitoneal protocols (often vancomycin ± ceftazidime/cefepime per ISPD) — not covered by this spontaneous/ascitic SBP card.
Enter weight on Kids to calculate doses
Gentamicin • i.v. • 5–7.5 mg/kg/day • 1×/day
Duration: 7–10 days · Extended-interval once daily (5–7.5 mg/kg/day) — alternative divided 2.5 mg/kg/dose q8h per local protocol; monitor levels
Enter weight on Kids to calculate doses
Clinical notes
• Diagnostic criteria: bacterial infection of ascitic/peritoneal fluid without surgically treatable source — clinical ascites with fever, abdominal pain, or toxicity plus paracentesis showing elevated neutrophils (≥250 PMN/mm³ adult SBP threshold; pediatric nephrotic protocols often >100 WBC/mm³ with >50% neutrophils) and typically monomicrobial Gram stain (SSNS, AASLD SBP principles).
• Perform diagnostic paracentesis before antibiotics when safe — send cell count, Gram stain, glucose, protein; inoculate ascitic fluid into blood culture bottles to maximize yield; obtain blood cultures (Nelson, IDSA diagnostic principles).
• Causative organisms: in nephrotic syndrome/cirrhosis — encapsulated organisms (S. pneumoniae most common in children) and E. coli; rare primary cases in healthy young children may involve pneumococcus, group A streptococci, or E. coli — mixed flora suggests secondary peritonitis.
• Empiric IV antibiotics indicated when diagnostic criteria for SBP/primary peritonitis are met — third-generation cephalosporin monotherapy (cefotaxime or ceftriaxone) is standard; do not withhold therapy while awaiting cultures if clinical suspicion is high (SSNS, pediatric nephrology consensus).
• Treat 7–10 days; switch i.v. → p.o. when afebrile ≥48 h and clinically improving per sensitivities. Urgent surgical consultation if mixed organisms, free intraperitoneal air, focal peritoneal signs refractory to antibiotics, or worsening sepsis — suggests secondary peritonitis requiring source control (Nelson, WSES, SIS).
• Indian Pediatrics / SSNS — Revised guidelines: infections in nephrotic syndrome (peritonitis) (2021)
• AASLD — Management of adult patients with ascites and SBP (principles applicable) (2021)
