Depends on agent
is defined as an inflamation(generally caused by infection) of the tissues surrounding the brain and spinal cord.
The agent may be bacterial (like strep/staph/meningococcus); viral, fungal or parocitic.Some viral cases are mild & resolve without special rx. Most bacterial are deadly if untreated & may damage even with rx. Fungal & paracitic causes are also deadly & often harder to rx.