Grand mal seizures occur when the electrical activity over the whole surface of the brain becomes abnormally synchronized. In general, seizures are caused by abnormal, rhythmic nerve cell (neuron) activity in the brain. The brain's nerve cells normally communicate with each other by sending electrical and chemical signals across the synapses that connect the cells. In people who have seizures, the brain's usual electrical activity is altered.

Exactly what causes the changes to occur remains unknown in about half the cases. However, grand mal seizures are sometimes caused by underlying health problems, such as:

  • Very low blood levels of glucose, sodium, calcium or magnesium
  • Traumatic head injuries
  • Using or withdrawing from drugs, including alcohol
  • Brain tumors
  • Strokes
  • Infections, such as encephalitis or meningitis, or history of such infection
  • Injury due to a previous lack of oxygen
  • Blood vessel malformations in the brain
  • Genetic syndromes
Jun. 23, 2011