A convulsion is a medical event in which nerve cell activity in the brain is disrupted, causing muscles to involuntarily contract and spasm. This results in sudden, violent, and irregular movements of the body. A convulsion is not the same thing as a seizure, but it can be a symptom of different types of seizures. Convulsions may be associated with any number of medical conditions, including epilepsy, a head injury, severe fever, an inflammatory brain infection, exposure to toxins, and certain medications. It often requires a doctor such as a neurologist or infectious disease specialist to determine the reason it has occurred. Once a cause has been diagnosed, the appropriate treatment can follow.