Diagnostic criteria:
  1. Headache previously fulfilling criteria for 9.1.1 Headache attributed to bacterial meningitis or meningoencephalitis, and fulfilling criterion C below
  2. Bacterial meningitis or meningoencephalitis has resolved
  3. Headache has persisted for >3 months after resolution of the bacterial meningitis or meningoencephalitis
  4. Not better accounted for by another ICHD-3 diagnosis.