Inclusion Criteria:  All children from one month of age to 14 years old with confirmed and full filling the diagnostic criteria of meningitis . Cases: children surely diagnosed with acute bacterial meningitis . Controls: children with suspected non-bacterial meningitis .  Exclusion Criteria:  neonates children with other systemic or focal infections children with other neurological problems(CNS hemorrhage or infarction, epilepsy and other causes of convulsions, cerebral palsy and other neurodegenerative and metabolic diseases)