💊 Chapter 100: Empiric Antimicrobials for Common Illnesses in PICU

Empiric therapy · De-escalation · Meningitis · Pneumonia · Sepsis · Intra-abdominal · Febrile neutropenia · UTI · CRBSI · MRSA · ESBL · Time-to-antibiotics

🔍 Core Concepts: Empiric Antimicrobials in PICU

⏱️ Golden hour principle
Antibiotics within 1 hour of severe sepsis/septic shock. Each hour delay increases mortality >7%.
🧫 Meningitis empiric
Ceftriaxone/cefotaxime + vancomycin (if PCN-resistant pneumococcus). Add ampicillin in neonates (Listeria). Dexamethasone if Hib suspected.
🫁 CAP & HAP
CAP: ceftriaxone + azithromycin. Severe CAP: meropenem/cefepime + vancomycin. HAP/VAP: anti-pseudomonal beta-lactam + aminoglycoside + MRSA cover.
🩸 Septic shock / MODS
Cefepime/meropenem + aminoglycoside + vancomycin (MRSA). De-escalate at 48h.
🪢 Intra-abdominal sepsis
Piperacillin-tazobactam or meropenem/ertapenem. Cover anaerobes, Enterobacteriaceae, Enterococcus.
🌡️ Febrile neutropenia
<7 days: meropenem/piperacillin-tazobactam. >7 days: add antifungal (caspofungin, voriconazole).
💧 UTI & Pyelonephritis
Ceftriaxone or fluoroquinolone. Complicated/comorbid: meropenem. Total 14 days.
⚙️ De-escalation & Stewardship
Review at 48h, narrow based on cultures. Limit aminoglycosides to 48h. Avoid unnecessary duration.

📋 Stepwise Approach: Empiric Antimicrobial Selection

1
Recognize severe sepsis/septic shock
Administer broad-spectrum antibiotics within 1 hour of triage. Obtain cultures before antibiotics if possible (do not delay >45 min).
2
Choose empiric regimen based on suspected source & local epidemiology
Meningitis: 3rd gen cephalosporin + vancomycin. CAP: ceftriaxone + macrolide. Intra-abdominal: pip-tazo or carbapenem. Neutropenia: antipseudomonal beta-lactam ± vancomycin ± antifungal.
3
Consider MRSA / ESBL / Pseudomonas risk factors
Recent hospitalization, prolonged ICU stay, immunocompromise, prior antibiotics → add vancomycin/linezolid and use carbapenem or cefepime.
4
Reassess at 48 hours: de-escalate or stop
Use culture & sensitivity data. Narrow to targeted therapy. Stop antibiotics if infection ruled out. Document planned duration.
5
Optimize dosing & source control
Source control (drainage, line removal) as important as antibiotics. Adjust doses for renal/hepatic function. Use therapeutic drug monitoring for aminoglycosides/vancomycin.