Acute bacterial meningitis in the newborn.

Acute bacterial meningitis is more common during the neonatal period than at any other time of life and is accompanied by a high incidence of mortality and long term significant sequelae. The incidence of neonatal meningitis is variously calculated at between 0.25 and 0.32 per 1000 live births depending on the inclusion criteria. There is no evidence that the incidence has changed during the last 25 years although during this time there have been dramatic changes in the neonatal population. The pathogenesis of neonatal meningitis is complex and not fully understood. The range of bacteria involved is wider than in paediatric meningitis. Mortality rates are highest following infection with enteric Gram-negative bacilli, and still exceed 30%, lower with the Lancefield group B streptococcus and lower still with other Gram-positive bacteria. The predisposing factors to neonatal meningitis are few with the exception of maternal infection or pyrexia at the time of delivery. Any association between meningitis and other possible predisposing factors has not been reliably established. There is evidence to suggest that meningitis in premature low birth weight and sickly babies is caused by organisms, usually from the maternal genital tract, which do not have recognized pathogenicity factors. In contrast, late onset infection is associated with organisms with recognized virulence and pathogenicity factors, many of which have a predisposition to the central nervous system. The clinical presentation of neonatal meningitis is non-specific and meningitic babies cannot be easily distinguished from those with other septic foci or sick uninfected babies. In consequence appropriate antibiotic therapy must be initiated as soon as meningitis is suspected. It is currently recommended that neonatal meningitis is treated with a third-generation cephalosporin, cefotaxime or ceftriaxone, with or without an aminoglycoside, usually gentamicin or amikacin. If there is a significant risk of infection with listeria or enterococci then ampicillin should also be given until CSF culture results are available. While steroids are extensively used for the treatment of paediatric meningitis there is no evidence to support their use in the treatment of neonatal infection. New therapeutic regimens are being developed which are intended to alleviate the pathophysiological consequences of endotoxin release which follows the administration of antibiotics.(ABSTRACT TRUNCATED AT 400 WORDS)