Mycoplasma pneumoniae infection associated with central nervous system complications.

We describe two children who had central nervous system complications, encephalitis and meningoencephalitis, temporally associated with Mycoplasma pneumoniae. M pneumoniae was identified as the cause of the illnesses on the basis of at least a fourfold increase in complement fixation antibody titers. Despite extensive viral and bacterial investigation, no evidence of any other pathogen was found. Two strategies were used to determine whether M pneumoniae was directly invasive: (1) by examining cerebrospinal fluid using a M pneumoniae-specific DNA probe and (2) by determining whether complement-fixating antibody to M pneumoniae was produced locally through comparison of the cerebrospinal fluid/serum ratio of M pneumoniae antibody to the cerebrospinal fluid/serum ratio of immunoglobulin M. Both assessments were negative. M pneumoniae did not appear to directly invade the central nervous system in these two patients. We conclude that the direct invasion of the cerebrospinal fluid is not necessary in the pathogenesis of M pneumoniae-induced neurologic disease.