Inflammation of brain and spinal cord meninges

Usually follows onset of respiratory symptoms

Sudden onset, causing serious illness within 24 hours

Good prognosis with viral meningitis; complications rare

If bacterial, causes acute infection in the subarachnoid space

Good prognosis if rare complications recognized early and infecting organism responsive to antibiotic therapy

In 10% to 15% of cases, bacterial meningitis fatal; sequelae common when occurring in the first 2 months of life

Condition common in infants and toddlers; incidence now greatly decreased with the routine administration of Haemophilus influenzae type B (Hib) vaccine

Viral or bacterial agents are transmitted by the spreading of droplets; organisms enter the blood from the nasopharynx or middle ear.

Inflammation may involve all three meningeal membranes — the dura mater, the arachnoid, and the pia mater.

Aseptic meningitis — viral (see Aseptic meningitis, page 140)

Vascular dissemination from focus of infection elsewhere in the body; infections possibly including or resulting from: