Meningitis is the development of an inflammatory reaction in the meningeal space, most often of infectious origin. Many pathogens can cause meningitis, the severity of which varies greatly. Patients presenting with a febrile meningeal syndrome are most often managed in the emergency room, where the challenge for physicians is to quickly differentiate bacterial and viral meningitis.

Viral meningitis is the most common, with enterovirus meningitis having a classically excellent prognosis. Bacterial meningitis is less frequent but more serious.The current public health objective is to save antibiotics.

Investigator hypothesizes that the BMS score can be used to exclude bacterial meningitis in the emergency department in an adult European population of patients with suspected bacterial meningitis.

Inclusion Criteria:

• Patient admitted to the Adult Emergency Department of CH Le Mans,CHU Angers, CHU Nantes or Beaujon Hospital.
• Over 18 years old
• Having had a lumbar puncture during their stay in the Adult Emergency Department
• Having had a diagnosis of meningitis defined as a pleocytosis ≥ 5leukocytes/mm3 after correction with CSF red blood cells at a standardized ratio of 500/1.

Exclusion Criteria:

• Antibiotic therapy within 72 hours of inclusion
• Immunosuppression from any cause
• Presence of petechiae or purpura
• History of recent neurosurgery or head trauma
• Other associated bacterial infection
• Inability to collect information for the BMS score calculation or primary endpoint (e.g., transfer to another facility)
• Minor or adult patient under guardianship or protection

The study population will be extracted from the population having consulted the Adult Emergency Departments of the Le Mans Hospital, the Angers and Nantes University Hospitals and the Beaujon University Hospital between January 1, 2009 and December 31, 2020 and for whom a lumbar puncture will have been performed for suspected meningitis.