Epilepsy - Causes

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Hippocampal Sclerosis. Hardened tissue (sclerosis) in the brain's hippocampus is the most commonly identified abnormality in patients with partial epilepsy. Such abnormal brain tissue leads to structural reorganization, and both the loss and regeneration of nerve cells.

Genetic Factors

Dozens of genetic syndromes representing a variety of seizure patterns may account for the different forms epilepsy. The following epilepsy syndromes are known to be caused by single genetic defects:

• Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). ADNFLE appears to be caused by an alteration in the brain receptor neuronal nicotinic acetylcholine.
• Benign familial neonatal convulsions (BFNC). BFNC appears to be caused by genetic defects that affect ion channels in nerve cells that carry potassium.
• Contactin-associated protein-like 2 (CASPR2). CASPR2 is associated with a childhood epilepsy and autism disorder found in closely related relatives in Amish communities.

A genetic cause has been identified for at least some cases of juvenile myoclonic epilepsy, which represents 10% of all epilepsy cases. (Such research and other studies have pointed to the GABA signaling system as an important player in many cases of epilepsy.)

Causes of Childhood Seizures

Febrile Seizures. Febrile seizures are caused by high fever. They usually occur in children ages 3 months - 5 years. Between 10 - 15% of children with epilepsy have a history of febrile seizures before they develop epilepsy. However, febrile seizures are quite common and occur in about 3% of all children under 5 years old. Nearly all are brief and have no long-lasting effect.

Vaccinations. In young children, high fever from a vaccination can, in rare instances, trigger seizures. These seizures are almost always temporary and have no serious consequences. Some controversy arose a few years ago over the possibility that the DTP (diphtheria-tetanus-pertussis) vaccine might trigger epilepsy or other neurologic diseases. Some experts suggest that children who have neurologic events following their DTP shot already have a preexisting impairment such as epilepsy, which is revealed, but not caused by, the vaccine. Children with existing epilepsy may be at risk for seizures 2 or 3 days after the vaccination. Infants with suspected neurologic problems may have their vaccinations delayed until their neurologic situation is clarified, but not beyond their first birthday.