Atlas of Neonatal Pathology: Sepsis neonatorum

+ Introduction

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+ Neonatal pathology

Sepsis neonatorum

Introduction

Bacterial sepsis occurring in the first 28 days of life characterized clinically by abrupt onset, rapid progression, often without demostrable anatomic localization and high mortality rate even with appropriate antibiotic treatment.

Clinical signs

inderteminate signs
lethargy, irratability
hypothermia or hyperthermia
respiratory distress
feeding disturbances
mild jaundice
seizures
apnea

Etiology

Gram-positive
- group βhemolytic Streptococcus group B — asymptomatic vaginal colonization is found in 15 – 25 % of pregnant women. Vertical transmission is up to 60%, but only 1% of these colonized infants develop neonatal disease. IGBS is associated with both early and late onset sepsis and the most common etiologic agent of neonatal meningitis. The presentation depends on the GBS serotype Listeria monocytogenes — early and late onset sepsis
- Staphylococcus aureus — septicemia, abscesses in the lungs, supurative skin infections, osteomyelitis
- Staphylococcus epidermidis — late onset sepsis, nosocomial infections associated with intravenous catheters or invasive procedures
Gram-negative
- E. coli — commonly encountered in sepsis, neonatal meningitis, nosocomial infections by strains with increased antibiotic resistance
- Klebsiella, Enterobacter
- Haemophilus influenzae

Classification

Early onset sepsis
Late onset sepsis

Clinical signs

Early onset sepsis
- manifests in the first 7 days of life, commonly in the first hours after birth
- associated with obstetric complications: premature delivery, chorioamnionitis, prolonged membrane rupture, prolonged labor, maternal fever
- the organism is acquired directly from the mothers genital tract or by swallowing or aspiration of infected amniotic fluid
- often due to group B βhemolytic Streptococcus
- fulminant clinical course, respiratory symptoms predominate
- mortality rate is very high
- the main pathological finding is widespread pneumonia, hyaline membranes may be superimposed
- lungs appear congested and airless
Late onset sepsis (7 – 28 days)
- present after 7th day of life, commonly during the second to fourth week after birth
- spread of microorganisms is either vertical (intrapartum contact with foci of maternal genital infection in most GBS sepsis) or from postnatal spread from the caregiving enviroment
- no associaton with obstetric complications
- mortality rate is lower than in early onset form
- Bacteriaemia results in meningeal seeding, neonatal menignitis and ventriculitis are typical. Clinical presention of meningitis is subtle and may be dominated by nonneural signs. Nuchal rigidity and bulging anterior fontanella are late. There is high incidence of hydrocephalus in survivors.

Pictures

Immaturity, pneumonia: Immaturity, pneumonia, Macro, autopsy (74412) Immaturity, pneumonia, Macro, autopsy (74413)