There are several types of meningitis depending on the causative factor:
Viral meningitis - Most common type of meningitis caused by enteroviruses.
Bacterial meningitis - It is rare, but can cause brain damage or death. Bacterial meningitis can be caused due to pneumococcal infections and meningococcal infections.
Sterile meningitis - It is caused due to systemic diseases, toxins, medications or malignancies.
Bacteria and virus causing meningitis spreads through the air as these micro-organisms are present in the respiratory and throat secretions. Viral meningitis can spread through stools also.
The infectious agents (bacteria, virus, fungus, parasites) enter the central nervous system (CNS) and replicate in an uncontrolled fashion resulting in meningeal inflammation. Meningitis can range from mild to life-threatening infections depending on the severity of the infecting organism, age of the person and his health condition.
Meningitis usually presents with a sudden fever, severe headache and a stiff neck, and can progress rapidly. It is usually diagnosed by analyzing the cerebrospinal fluid (CSF).
Early treatment of meningitis with the appropriate drugs can help prevent complications, including permanent neurological damage and death. Bacterial meningitis may take several days to few weeks to respond, while viral meningitis resolves within few days.
Hemophilus influenza type B vaccine (HiB vaccine) can prevent H.influenza meningitis. Also, the pneumococcal conjugate vaccine is very effective at preventing pneumococcal meningitis.