What is Meningitis?
Meningitis is inflammation of the meninges that results in swelling of brain tissue and sometimes spinal tissue (spinal meningitis). Swelling inhibits the flow of blood and oxygen to brain tissue. The characteristic symptoms of meningitis are stiff neck, severe headache, and fever. The meninges are three ultrathin membranes that surround and protect the brain and a portion of the spinal cord: the outer membrane (dura mater), middle membrane (arachnoid), and inner membrane (pia mater). Meningitis is either infectious (contagious) or noninfectious. Infectious meningitis is classified as viral, bacterial, fungal, or parasitic, depending on the type of organism causing the infection.