Epilepsy - Causes

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 is now believed 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.

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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 age three months to five years. Between 10% and 15% of children with epilepsy have a history of febrile seizures before they develop the disease. It should be strongly noted, however, that febrile seizures are quite common and occur in about 3% of all children under five 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 two or three 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.

Head Injuries in Infants and Children. Infants are at high risk for head trauma. In fact, one study suggested that any infant who had a scalp fracture with a hematoma may be at risk for brain injury. A hematoma is a swelling caused by a broken blood vessel, which creates a large purplish hue like a buise. It should be noted that hematoma is quite common after childbirth, but typically causes no problems.

Childhood Viral Infections. A 2001 study of 22 children with status epilepticus (sustained periods of convulsions) revealed that presence of several pediatric viruses. Human herpesvirus 6 was particularly associated with severe seizures. Herpesvirus 6 is common in children and causes roseola infantum, an acute, but usually benign, illness that can lead to high fever and skin rash.