Aseptic meningitis in the newborn and young infant.

When a toxic newborn or young infant presents with fever and lethargy or irritability, it is important to consider the diagnosis of meningitis even if the classic localizing signs and symptoms are absent. Cerebrospinal fluid should be obtained (unless lumbar puncture is clinically contraindicated) to enable initial therapy to be planned. Initial results of cerebrospinal fluid testing may not conclusively differentiate between aseptic and bacterial meningitis, and antimicrobial therapy for all likely organisms should be instituted until definitive culture results are available. Comprehensive therapy, including antibacterial and antiviral agents, should continue until a cause is identified and more specific therapy is initiated, an etiology is excluded or the patient improves considerably and the course of antimicrobial therapy is completed. Group B streptococcus is the most common bacterial etiologic agent in cases of meningitis that occur during the first month after birth. Etiologies of aseptic meningitis include viral infection, partially treated bacterial meningitis, congenital infections, drug reactions, postvaccination complications, systemic diseases and malignancy. Long-term sequelae of meningitis include neuromuscular impairments, learning disabilities and hearing loss. Prompt diagnosis and treatment are essential to improved outcome.