Seizures in bacterial meningitis: prevalence, patterns, pathogenesis, and prognosis.

Of 207 patients with acute bacterial meningitis previously reported by Dodge and Swartz, seizures occurred in 56 (27%). Most seizures began on the first or second day, and most stopped within two days. Seizures occurred most often at the extremes of life. Age-adjusted seizure frequency was greater with Hemophilus influenzae meningitis than with Streptococcus pneumoniae or Neisseria meningitidis. When seizures complicated bacterial meningitis, age-corrected mortality increased from 24% to 38%. Though seizures after recovery were infrequent (2.7% of cases), recurrences were five times more frequent in patients who convulsed acutely than in those who did not. When focal seizures accompanied focal pathology (extracranial or intracranial), the seizures were usually not lateralized to the opposite side of the body. Of factors of potential importance in causation of seizures, fever was the most important risk factor regardless of patient age.