Neonatal meningitis

Introduction
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By Francis M Filloux MD

Neonatal meningitis represents an important clinical challenge for both the child neurologist and the pediatrician. The clinical presentation of meningitis in newborn infants is frequently nonspecific, and spinal fluid abnormalities may be difficult to differentiate from values typically seen in newborn infants. For this reason, meningitis should be suspected in a newborn who develops poor feeding, irritability, fever, or hypothermia; this is frequently, but not invariably, accompanied by a CSF white blood cell count greater than 30 cells/mm3 and a CSF:serum glucose ratio less than 0.5. Seizures may also suggest the presence of meningitis, although clinical seizures in the newborn may be more subtle or atypical than those seen in older children or adults. Empiric antimicrobial therapy includes a combination of ampicillin and a third- or fourth-generation cephalosporin. Although adjunctive dexamethasone therapy is recommended in children and adults, there is insufficient evidence to date to recommend dexamethasone therapy for neonatal meningitis.

Key Points

  • Neonatal meningitis includes infections occurring within the immediate postpartum period and also infections occurring during the first few weeks of life. The condition is usually divided into cases occurring within 72 hours of delivery (early onset) and cases occurring after 72 hours postpartum (late onset).
  • The major causes of neonatal meningitis are Streptococcus agalactiae (Group B streptococci, GBS) and Gram-negative organisms, in particular Escherichia coli. The diagnosis of neonatal meningitis is often difficult. Typical signs of meningeal inflammation are frequently absent, and neonates may present with nonspecific irritability. The neonate may be febrile, euthermic, or hypothermic and may be tachypneic, have apneic spells, or be excessively somnolent. Seizures may occur, but may not resemble seizures seen in older children or adults.
  • CSF findings in neonatal meningitis may not easily be distinguished from CSF values typically seen in neonates. However, meningitis should be strongly suspected if CSF white blood cell count is greater than 30 cells/mm3 and the CSF:serum glucose ratio is less than 0.5.
  • Empiric treatment of neonatal meningitis involves use of a third- or fourth-generation cephalosporin to cover S agalactiae and Gram-negative organisms, plus ampicillin to cover Listeria monocytogenes.
  • Aminoglycosides such as gentamicin do not reliably reach therapeutic concentrations in CSF, and intrathecal administration of these agents has not been effective. Intraventricular administration has been found to increase mortality and is contraindicated.
  • Intrapartum administration of antibiotics to mothers infected with S agalactiae has proven crucial to preventing meningitis in the newborn infant.

In This Article

Introduction
Historical note and nomenclature
Clinical manifestations
Clinical vignette
Etiology
Pathogenesis and pathophysiology
Epidemiology
Prevention
Differential diagnosis
Diagnostic workup
Prognosis and complications
Management
Pregnancy
References cited
Contributors