Pneumococcal meningitis: antibiotics essential but insufficient.

to the discovery of antibiotics, bacterial meningitis was almost invariably fatal: over 95% of individuals developing bacterial meningitis died, and the few individuals surviving infection were neurologically devastated. With the advent of antibiotics, bacterial meningitis became a treatable condition, and the primary objective in the patient with bacterial meningitis became, appropriately, prompt diagnosis and initiation of antibiotic therapy. Until the latter part of the twentieth century, bacterial meningitis was predominantly a condition of infancy and early childhood, caused in large part by Haemophilus in¯uenzae type B. Streptococcus pneumoniae, although the most common cause of meningitis in adults, received relatively little attention in terms of its pathogenesis, mechanisms of injury, and optimal therapy. Immunization against Haemophilus in¯uenzae type B brought about a profound decrease in cases of early childhood meningitis in developed countries. Streptococcus pneumoniae is now the most common agent of bacterial meningitis for children as well as adults (Schuchat et al., 1997). The article by Kastenbauer et al., in this issue of Brain, reminds us that there is much about the pathogenesis of pneumococcal meningitis which we still do not understand and that, despite antibiotics, current therapy of S. pneumoniae meningitis leaves much to be desired. S. pneumoniae is, for the most part, highly sensitive to antibiotics, yet mortality from pneumococcal meningitis remains high (24.1%) despite antibiotic therapy, and survivors are often neurologically damaged (36.4%). As Kastenbauer et al. point out, neuro-logical injury in S. pneumoniae meningitis is not only due to meningeal in¯ammation but also to cerebral vasculitis, cerebral edema, cerebral necrosis and hydrocephalus. Less frequently appreciated, but still signi®cant in terms of neurological injury, is the ability of the infection to cause intracranial hemorrhage as a complication of the accompanying vasculitis and, in a few cases, to cause myelitis. Hearing loss, although thought to be primarily a complication of childhood pneumococcal meningitis, was found in 20% of Kastenbauer's adult survivors. Kastenbauer et al. point out that pneumococcal meningitis mainly occurs in three groups of patients: 1) adults with chronic debilitating conditions such as chronic alcoholism, malignancies, chronic immunosuppressive therapy, or poorly controlled diabetes mellitus; 2) patients with asplenia; and 3) previously healthy adults with acute infections such as otitis, sinusitis, pneumonia, or endocarditis. Their article also emphasizes the importance of pneumococcal meningitis as a systemic as well as neurological condition: death in pneumococcal meningitis may result from the central nervous system infection itself, from pneumococcal sepsis with …