Most cases of meningitis are caused by microorganisms, such as viruses, bacteria, fungi, or parasite, that spread through blood and into the cerebrospinal fluid (CSF).   Non-infectious causes include cancer, systemic lupus erythematosus and certain drugs.   The most common cause of meningitis is viral, and often runs its course within a few days. Bacterial meningitis is the second most frequent type and can be serious and life-threatening.  Numerous microorganisms may cause bacterial meningitis, but Neisseria meningitidis and Streptococcus pneumoniae are the most common pathogens in patients without immune deficiency, with meningococcal disease being more common in children.  Staphylococcus aureus may complicate neurosurgical operations, and Listeria monocytogenes is associated with poor nutritional state and alcoholicism.  Haemophilus influenzae (type B) incidence has been much reduced by immunization in many countries.  Mycobacterium tuberculosis (the causative agent of tuberculosis) rarely causes meningitis in Western countries but is common and feared in countries where tuberculosis is endemic.
Meningitis causes
Meningococcemia causes
Bacterial meningitis causes
Brain abscess causes
Neoplastic meningitis causes
Conjunctivitis causes
Viral meningitis causes
Fungal meningitis causes