Acute Treatment and Long-term Assessment of Adult Infectious Meningitis

Inclusion Criteria: Both sexes, aged ≥ 18 years, meeting one or more of the criteria (A, B or C) below: --\> Criterion A: Clinical presentation compatible with a suspected case of meningitis or meningococcal disease: Fever ≥ 37.8 °C (axillary) associated with at least two of the following: * Severe headache * Vomiting * Altered level of consciousness (confusion, drowsiness, irritability) * Photophobia * Seizure OR Fever associated with one of the classic signs of meningeal irritation (neck stiffness, Kernig or Brudzinski signs) OR Sudden-onset fever with petechial rash or hemorrhagic suffusions * Criterion B: Cerebrospinal fluid with leukocytes ≥ 5 cells/mm³ (corrected for red blood cell count at 1:500) * Criterion C: Confirmed etiological diagnosis of meningitis or meningococcal disease with no more than 48 hours between pathogen confirmation and signature of the informed consent form by the participant or legal representative. Exclusion criteria * Refusal to provide consent for the study. * Presence of a neurological condition, other than meningitis, that accounts for the current clinical picture. * Clinical, laboratory or radiological evidence of an alternative infectious focus that accounts for the current clinical picture. * Use of an intraventricular device prior to study inclusion. * Etiological diagnosis of meningitis or meningococcal disease confirmed more than 48 hours earlier.