What causes children epilepsy?
Epilepsy is characterized by repeated seizures that may occur as often as several times a day, or as infrequently as once every few months. Normally, millions of tiny electrical charges pass between nerve cells in the brain and throughout the body to control the body's many functions. Epileptic seizures are caused by unusual and strong bursts of electrical energy in the brain. There are many possible causes of epilepsy in children, including: problems with brain development before birth; lack of oxygen during or following birth; a head injury that leaves a scar in the brain; unusual structures in the brain;
tumors; a prolonged seizure with fever, or the after-effects of severe brain infections such as meningitis or encephalitis. When a cause can be identified, children will be described as having symptomatic epilepsy. The seizures are thought to be a symptom of the underlying brain injury.
Febrile seizures. Febrile seizures are caused by high fever and usually occur between the ages of three months and 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.
Genetic factors. Epilepsy may be the most common genetic neurologic disease, but dozens of genetic syndromes representing a variety of seizure patterns may account for the different forms this disease takes. To date, however, researchers have identified only two epilepsy syndromes that 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 a receptor in the brain called 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.
Vaccinations. In the womanng children, high fever from a vaccination can, in rare instances, trigger seizures, which 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. Such a temporary worsening of their disease does not appear to pose a danger to the child. 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 with scalp fracture that occurs with a hematoma may be at risk for brain injury. A hematoma occurs after an injury when blood collects in a mass that usually looks like a large purplish area. It should be noted that hematoma is quite common after delivery when it typically causes no problems.
Childhood viral infections. According to a 2001 study of 22 children with status epilepticus (sustained periods of convulsions), viral testing uncovered the 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 illness that can lead to high fever and skin rash but is usually benign.
Hydrocephalus and shunts. Hydrocephalus is a condition that may occur in newborns and infants in which cerebrospinal fluid (CSF) accumulates in the brain, leading to excessive swelling of the spaces in the brain ( ventricles). The resulting pressure can damage the brain's tissue. Hydrocephalus itself is not commonly known to cause seizures, but its treatment, which involves insertion of a shunt, may be. The shunt is a device that drains the excess fluid from the brain to other parts of the body, as well as to a special reservoir that allows the shunt to be reached through the skin. One 2001 study noted that between 20% and 50% of shunted children may experience epileptic seizures, particularly if the shunt is placed before age two. More research on its relationship to epileptic seizures is clearly needed.
Cortical dysplasias. This is an abnormality in fetal development in which the normal migration of nerve cells is altered.
Other causes in children. Seizures in infants and children may be due to birth defects, difficulties during delivery, or poisoning. Of note, melatonin, an herbal remedy available over the counter for sleep disorders, has been found to cause seizures in children who have existing neurologic problems.