Brain infections are very serious and can be fatal. They can be caused by:
Infections that involve only the brain are called encephalitis. Infections that involve the layers of tissue (meninges) that cover the brain and spinal cord are called meningitis. But encephalitis can spread and cause meningitis. And sometimes meningitis spreads to cause encephalitis.
Brain infections from a virus usually affect your whole brain. Brain infections caused by bacteria sometimes cause a pocket of pus, called a brain abscess.
Infections usually start somewhere else. They can get to your brain and meninges in several ways:
Infections that spread through your blood sometimes come from bug bites, particularly from mosquitoes and ticks.
Doctors try to treat the cause of the infection. Antiviral drugs or antibiotics work for some infections but not all. Doctors also give medicine to relieve symptoms. If needed, they may put the person on a ventilator or give treatments to support the person's blood pressure.