Atlas of Neonatal Pathology: Perinatal infection

+ Introduction

+ Support

+ Neonatal pathology

Perinatal infection

Introduction

Infections make a major contriution to perinatal mortality and morbidity. The fetus and neonate are particulary vulnerable to infection because of humotal and cellular defence mechanisms are inadequately developed. The situations resembles taht of the immunosupressed adult. The signs of infectin may be diffucult to distinguish from those of birth asphyxia or respiratory distress syndrom. Infections and sepsis as a major problem in preterm infants.

Etiology

General routes of infection

Transplacental (hematologic)
- used by most viruses and parasites (TORCH infections):
  - toxoplasmosis
  - rubella
  - cytomegalovirus
  - herpes simplex (TORCH infections)
  - parvovirus B19
  - Treponema pallidum
  - Listeria monocytogenes etc.
Ascending (transcervical) infection
- organisms ascend from maternal genital tract
- the neonate acquires the infection by swallowing and aspiration of infected amniotic fluid or during the passage through the birth canal
- frequently used by
  - bacteria (β-Streptococci of group B)
  - Escherichia coli and other bowel bacteria)
  - Candida sp.
  - herpesvirus may be acquired from focal herpetic lesions in the birth canal
Iatrogenic
- Amniocentesis, cordocentesis, exchange transfusion, cerclage
Postpartum
- Organisms spread from maternal or enviromental sources (sick persons, asymptomatic carrers with bacterial colonization). The infection is usually transmitted by hands of caregivers. Bacteria in particular, less viruses and fungi are implicated. Cytomegalovirus and HIV virus may be transmitted via brest feeding. The umbilicus provides a potential site of entry of microorganism, but umbilical sepsis is quite a rare occurence nowadays. Hospital-acquired infections (nosocomial) are the constant hazard for newborns hospitalized in intensive care units.

Intrauterine infections (TORCH group)

Sepsis neonatorum

Blenorrhea neonatorum

HIV infection