USMLE Prep - Medical Reference Library

Early‑Onset Neonatal Sepsis — Evaluation & Management

System: Pediatrics • Reviewed: Aug 31, 2025 • Step 1Step 2Step 3

Synopsis:

Stratify risk using maternal factors and neonatal exam; use multivariate risk calculators or categorical approach; obtain blood cultures when treating; narrow/stop antibiotics by 36–48 h if cultures negative and infant well.

Key Points

  • Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
  • Use system-specific risk tools to guide testing and disposition.
  • Order high-yield tests first; escalate imaging when indicated.
  • Start evidence-based initial therapy and reassess frequently.

Algorithm

  1. Primary survey and vitals; IV access and monitors.
  2. Focused history/physical; identify red flags and likely etiologies.
  3. Order system-appropriate labs and imaging (see Investigations).
  4. Initiate guideline-based empiric therapy (see Pharmacology).
  5. Reassess response; arrange consultation and definitive management.

Clinical Synopsis & Reasoning

Sepsis represents dysregulated host response with life‑threatening organ dysfunction; prioritize rapid recognition using qSOFA/SOFA elements, attention to mentation, perfusion, and lactate trends. Clinically, integrate history for potential sources (pulmonary, urinary, abdominal, device‑related), examine for shock phenotypes, and obtain paired blood cultures without delaying therapy. Point‑of‑care ultrasound refines volume status and source hypotheses (e.g., pneumonia, cholecystitis, obstructive uropathy). Early identification of patients likely to decompensate guides ICU triage and invasive monitoring.


Treatment Strategy & Disposition

Initiate balanced crystalloid resuscitation targeting MAP ≥65 mmHg and improving capillary refill/lactate; start time‑appropriate empiric antibiotics within 60 min tailored to suspected source and local resistance. If hypotension persists after 30 mL/kg or sooner when indicated, begin norepinephrine and titrate to perfusion targets; add vasopressin for catecholamine‑sparing effects. Pursue urgent source control (drainage, device removal, debridement) and de‑escalate antimicrobials with culture data. Disposition hinges on shock and organ failure—ICU for vasopressors/respiratory support; otherwise step‑down/ward with protocolized reassessment.


Management Notes

Avoid routine lumbar puncture unless high suspicion or positive cultures. Stewardship reduces resistance and dysbiosis.


Epidemiology / Risk Factors

  • Risk factors vary by condition and patient profile

Investigations

TestRole / RationaleTypical FindingsNotes
CBCBaseline hematologyAbnormal counts
BMPElectrolytes/renalDerangements

When to Treat

ScenarioAction
Chorioamnionitis or ill‑appearing infantStart empiric antibiotics
Borderline risk, well infantEnhanced observation ± labs
Term, low riskRoutine care
PretermLower threshold for evaluation
Negative cultures at 36–48 hDiscontinue if well

Pharmacology

MedicationMechanismOnsetRole in TherapyLimitations
Broad empiric antibioticsBactericidal (varies)VariableStart within 1 hour; de-escalate to sourceAllergy, resistance
Norepinephrineα1-adrenergic agonistMinutesFirst-line vasopressor to target MAP ≥65 mmHgArrhythmia, ischemia
Vasopressin (adjunct)V1 receptor agonistMinutesCatecholamine-sparing add-on in refractory shockIschemia at high dose
Hydrocortisone (refractory shock)GlucocorticoidHoursAdjunct in pressor-refractory septic shockHyperglycemia, infection risk
Balanced crystalloidsPlasma volume expansionImmediateInitial resuscitation (e.g., 30 mL/kg)Fluid overload; monitor oxygenation

Prognosis / Complications

  • Prognosis depends on severity, comorbidities, and timeliness of care

Patient Education / Counseling

  • Explain red flags and when to seek emergent care.
  • Reinforce medication adherence and follow-up plan.

References

  1. AAP/CDC EOS Guidance — Link