The most common is high fever convulsions, some viral or bacterial infections that cause generalized high fever can lead to abnormal brain cell activity, resulting in abnormal discharge, temporary convulsions, foaming at the mouth and other symptoms. 2, seizures, some primary and secondary brain diseases can appear seizures, and they are irregular. . 3, brain injury, usually after traumatic brain injury, brain contusion, brain hemorrhage, skull depression fracture, stimulation of the brain may also appear sudden convulsions, foaming at the mouth symptoms.