1. Are meningitis and encephalitis always caused by infections?
Very rarely, meningitis and encephalitis may be due to a non-infectious cause. This may include an autoimmune disorder that targets components of the nervous system, a reaction to a drug treatment, or certain cancers.

2. Can other conditions have similar symptoms?
Other serious conditions can cause some of the same symptoms as meningitis and encephalitis but have different causes and treatments. These include a brain abscess, brain lesion, drugs, trauma, or subdural empyema - a collection of pus in the space between the dura mater and arachnoid layers of the meninges.

3. Does meningitis and encephalitis start in the brain?
Meningitis can be caused by an infection in the blood or an infection in close proximity to the brain (ear infection) that allows the organisms to enter the CSF, or head trauma that allows bacteria in the sinuses to cross the blood-brain barrier. Encephalitis can be caused by infections that originate in the respiratory tract, gastrointestinal tract, or the blood that can spread to the central nervous system.

4. Is meningitis contagious?
It depends on the microorganism that is causing meningitis. People who have been exposed to someone who has meningococcal meningitis may be prescribed antibiotics for a few days to minimize their chance of developing it. There are vaccinations available for Streptococcus pneumoniae, Haemophilus influenzae type b and Neisseria meningitidis that are the most common causes of bacterial meningitis and can be transmitted to others in respiratory secretions.