Encephalitis - Description

Inflammation of the brain is a reaction of the body's immune system. The immune system is a network of cells, tissues, and chemical substances designed to protect the body against invasion by foreign agents. Sometimes, a foreign agent gets directly into the brain. In the process of fighting off the foreign agent, brain tissues become swollen and inflamed. In other cases, the infection occurs elsewhere in the body, such as the throat or neck. The immune reaction to those infections can also cause inflammation of the brain.