Neonatal Infections

Intro to Neonatal Sepsis - Tiny Patient Threat

Neonatal sepsis: Systemic infection in newborns. Suspect with $\geq$2 SIRS criteria (temp instability, tachycardia/bradycardia, tachypnea/apnea, abnormal WBC count/differential).

• Classification & Transmission:

  Feature	Early Onset Sepsis (EOS)	Late Onset Sepsis (LOS)
  Onset	<72 hours of life	>72 hours of life
  Typical Source	Maternal genital tract (intrapartum)	Healthcare-associated or community-acquired

• Routes of Transmission:

  • Vertical: Ascending (chorioamnionitis), intrapartum (infected birth canal).
  • Horizontal: Nosocomial (hospital-acquired), community-acquired.

⭐ Early Onset Sepsis (EOS) typically presents within the first 72 hours of life, often due to organisms acquired from the mother.

📌 Sepsis In Newborns Generally Early or Late (SIRS criteria, EOS/LOS distinction).

Etiology & Risk Factors - Bug Invasion

Pathogens:

Risk Factors:

• Maternal:
  • Prolonged Rupture of Membranes (PROM ≥18 hrs)
  • Chorioamnionitis
  • Maternal GBS colonization
  • Intrapartum fever (≥38°C)
• Neonatal:
  • Prematurity (<37 wks)
  • Low Birth Weight (LBW <2500g), Very Low Birth Weight (VLBW <1500g)
  • Invasive procedures (e.g., central lines, endotracheal intubation)
  • Prolonged hospitalization

⭐ Group B Streptococcus (GBS) is the leading cause of Early Onset Sepsis (EOS).

Clinical Signs & Diagnosis - Sepsis Detective

• Clinical Signs (Often Subtle):

  • Temperature instability (fever/hypothermia)
  • Lethargy, irritability, poor tone
  • Poor feeding, vomiting, abdominal distension
  • Respiratory distress (grunting, tachypnea, apnea)
  • Jaundice (prolonged/worsening)
  • Tachycardia, poor perfusion, hypotension (late)
  • 📌 TEMP: Temperature instability, Eating problems, Mentation changes, Poor perfusion.

• Sepsis Workup:

  • Blood Culture: Gold standard.

    ⭐ A blood culture is the gold standard for diagnosing neonatal sepsis.

  • CBC with Differential:
    • Leukocytosis/leukopenia, neutropenia, thrombocytopenia.
    • I/T ratio (Immature/Total Neutrophils) > 0.2 is significant.
  • Acute Phase Reactants:
    • CRP (C-Reactive Protein): ↑ (serial useful).
    • Procalcitonin (PCT): ↑ (rises earlier, more specific).

• Other Investigations (Guided by Clinical Picture):

  • Lumbar Puncture (LP): For suspected meningitis (CSF analysis & culture).
  • Urine Culture: Especially in Late Onset Sepsis (LOS) or if UTI suspected.
  • Chest X-Ray (CXR): If respiratory signs present (pneumonia).

Management & Prevention - Shield & Sword

• Empirical Antibiotic Therapy:

  Onset Type	First-line Antibiotics	Notes
  Early Onset (EOS)	Ampicillin + Gentamicin	Covers GBS, E.coli
  Late Onset (LOS)	Vancomycin + (Cefotaxime or Gentamicin)	Covers Staph, Gram-negatives; Add antifungal if risk factors

• Duration of Therapy:

  • Uncomplicated bacteremia: 7-10 days.
  • Meningitis/Osteomyelitis: 14-21 days.

• Supportive Care:

  • IV fluids, Oxygen, Respiratory support (CPAP/Ventilation), Inotropes if shock.

• Prevention - The Shield:

  • Maternal GBS screening (35-37 weeks) & Intrapartum Antibiotic Prophylaxis (IAP e.g., Penicillin G).
  • Strict hand hygiene.
  • Aseptic precautions during procedures.

⭐ Empirical therapy for Early Onset Sepsis (EOS) is typically Ampicillin + Gentamicin.

High‑Yield Points - ⚡ Biggest Takeaways

• Group B Streptococcus (GBS): leading cause of early-onset sepsis (EOS); prevent with intrapartum antibiotics.
• Late-onset sepsis (LOS): often Coagulase-negative Staphylococci (CoNS) or Gram-negatives, especially in preterm infants.
• Empiric therapy for sepsis: Ampicillin and Gentamicin.
• Chorioamnionitis and prolonged membrane rupture are key risk factors for EOS.
• TORCH infections (CMV, Rubella, Toxoplasma, Syphilis, HSV) cause distinct congenital syndromes.
• Neonatal meningitis presents non-specifically; lumbar puncture is crucial for diagnosis.