Meningitis is most often caused by infection with several species of bacteria, viruses, rarely by fungi and parasites. Bacterial meningitis is the most common and dangerous type of meningitis and can be fatal within 24 hours if untreated. The highest global burden is seen with bacterial meningitis. Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis are the most common causes of bacterial meningitis.
Although meningitis affects all ages, young children are most at risk. New-born babies are at most risk from Group B streptococcus, young children are at higher risk from meningococcus, pneumococcus and Haemophilus influenzae.
Clinical features of patients with meningitis vary depending on the cause, disease course (acute, subacute or chronic), brain involvement (meningo-encephalitis) and systemic complications (e.g., sepsis). Common symptoms of meningitis are neck stiffness, fever, confusion or altered mental status, headaches, nausea and vomiting.
One in 5 people surviving an episode of bacterial meningitis may have long lasting after-effects. These after-effects include hearing loss, seizures, limb weakness, difficulties with vision, speech, language, memory, and communication, as well as scarring and limb amputations after sepsis.
