While typically a grand mal seizure is the result of abnormal electrical activity in the brain associated with epilepsy, other possible triggers include stroke, high fever or very low blood sugar, according to Mayo Clinic. Traumatic head injuries, oxygen deprivation and infections can cause seizures as well.
Congenital or developmental conditions associated with genetic disorders, brain tumors or blood vessel irregularities in the brain can cause grand mal seizures, explains Mayo Clinic. Abnormally low levels of blood glucose, calcium, magnesium or sodium sometimes trigger a seizure, as can alcohol or drug withdrawal. In approximately half the cases, doctors don't know the exact cause of the alteration in the brains electrical activity that is responsible for seizures.
An entire grand mal, or tonic-clonic, seizure lasts about two minutes and starts with a sudden loss of consciousness and a stiffening of the body as the muscles contract, states WebMD. The individual sometimes vocalizes as the back and neck arch, and her skin may turn blue if breathing stops. Over the next 45 seconds, the muscles convulse, and she may lose bladder or bowel control. Some individuals bite their tongues during this clonic phase. When the seizure ends, it may take up to 30 minutes for the individual to regain consciousness, and she may be sleepy and confused, experiencing muscle aches and a headache for the next 24 hours.