Aseptic Meningitis in Infants Younger Than 2 Years of Age: Acute Illness and Neurologic Complications

Abstract

We report the clinical features and cerebrospinal fluid (CSF) laboratory values for 277 children younger than 24 months of age with aseptic meningitis who were prospectively evaluated at three Baltimore hospitals between July 1986 and December 1990. A major objective was to define the incidence, etiology, and outcome of neurologic complications occurring during the acute illness. Cases were identified by surveillance in the ambulatory care departments of each of the three hospitals, pertinent historical and clinical data were obtained by interview of the parents and by review of the medical records, initial CSF laboratory values were recorded, and appropriate specimens were submitted to determine the viral etiology. A subset of 216 children who participated in a long-term natural history study were followed periodically with neurologic examinations and formal neurodevelopmental testing. Most cases occurred in very young infants; 63.5% of patients were 8 weeks of age or younger, and 84.1% were younger than 16 weeks of age. In this very young cohort, the dominant symptoms were fever and irritability; only 8.7% had evidence of meningeal irritation at the initial examination. The acute illness was complicated by either complex seizures, physical evidence of increased intracranial pressure, or coma in 25 (9.0%) cases. Within the age group under study, these complications were each significantly more likely to occur in patients older than 12 weeks of age than in younger infants. The risk of neurologic complications was similar among infants infected with group B coxsackieviruses and echoviruses, the two major enterovirus classes observed to cause disease. Acute central nervous system (CNS) complications could not be correlated with extremely abnormal CSF laboratory indices. Importantly, there was no risk of long-term neurologic sequelae attributable to acute CNS complications. While approximately 9% of infants and children younger than 2 years of age with aseptic meningitis experience acute CNS complications in the form of complex seizures, increased intracranial pressure, or coma, the prognosis for long-term cognitive development appears to be as favorable as the prognosis for children with aseptic meningitis who do not experience these complications.