What Causes Epilepsy?
Epilepsy is a disorder with many possible causes. Anything that disturbs the normal pattern of neuron activity, from illness to brain damage to abnormal brain development can lead to seizures, causes of epilepsy usually involve some form of injury to the brain or any condition that affects brain function. For most people, though, epilepsy's causes aren't known, On the other hand, acute neurologic conditions such as stroke or trauma may produce structural damage to the brain. Even functionally minor damage can permanently alter neuronal excitability and synchronization, resulting in a tendency toward recurrent unprovoked seizures.
There is a clear cause for epilepsy in only a minority of the cases.
Because epilepsy has so many causes and can be linked to a number of other conditions, it is sometimes very difficult to determine the cause of a particular case.
Some of the main causes of epilepsy include:
Epilepsy may develop because of an abnormality in brain wiring, an imbalance of nerve signaling chemicals called neurotransmitters, or some combination of these factors.
Researchers think that some people who have epilepsy have too much of a neurotransmitter that increases impulse transmission and others have too little of neurotransmitters that reduce transmission.
Either situation can result in too much neuronal activity and cause epilepsy. One of the most-studied neurotransmitters that plays a role in epilepsy is GABA, or gamma-aminobutyric acid, which is an inhibitory neurotransmitter. Research on GABA has led to drugs that alter the amount of this neurotransmitter in the brain or change how the brain responds to it. Researchers also are studying excitatory neurotransmitters such as glutamate.
Epilepsy may also be caused by changes in brain cells called glia. Glia regulate concentrations of chemicals in the brain that can change the way neurons signal.
In some cases, the brain's attempts to repair itself after a head injury, stroke, or other problem may inadvertently generate abnormal nerve connections that lead to epilepsy. Abnormalities in brain wiring that occur during brain development also may disturb neuronal activity and lead to epilepsy.
The tendency to abnormal brain chemistry can sometimes be inherited and can sometimes be caused by an injury or a disease.
Dozens of genetic syndromes representing a variety of seizure patterns may account for the different forms epilepsy.
There is strong evidence that genetics may cause or contribute to many types of epilepsy.
A hereditary component in the susceptibility to epilepsy has been suspected for many years, but only in the last few decades has progress been made in identification of specific genetic influences on epilepsy.
Genetic abnormalities may be some of the most important factors contributing to epilepsy. Some types of epilepsy have been traced to an abnormality in a specific gene. Many other types of epilepsy tend to run in families, which suggests that genes influence epilepsy. Some researchers estimate that more than 500 genes could play a role in this disorder. However, it is increasingly clear that, for many forms of epilepsy, genetic abnormalities play only a partial role, perhaps by increasing a person's susceptibility to seizures that are triggered by an environmental factor.
Hereditary factors are not always a direct cause of epilepsy but may influence the disease indirectly. Genes can affect the way people process drugs or can cause areas of malformed neurons in the brain.
low oxygen during birth and Low blood sugar or sodium levels in the blood
Head injuries that occur during birth and labor or from accidents during youth or adulthood can in some cases cause epilepsy.
If the head injury is severe, the seizures may not begin until years later. If the injury is mild, the risk is slight.
Prenatal Injury and Developmental Problems:
In a fetus, the developing brain is susceptible to prenatal injuries that may occur if the pregnant mother has an infection, doesn't eat properly, smokes or abuses drugs or alcohol. These conditions may cause cerebral palsy.
About 20 percent of seizures in children are due to cerebral palsy or other neurological abnormalities.
Tumors (such as brain tumorbrain tumor) or other structural brain lesions (such as bleeding in the brain)
Traumatic brain injury, Illnesses that cause the brain to deteriorate, stroke, heart attacks and other conditions that affect the blood supply to the brain
Alcoholism and stopping alcohol after drinking heavily on most days
Dementia such as Alzheimer's disease
Kidney or liver failure
Use of cocaine, amphetamines, or certain other recreational drugs
Stopping certain drugs, such as barbiturates, painkillers (morphine, gabapentin) and sleeping pills, after taking them for a period of time
Infections and infectious diseases such as brain abscess, AIDS, meningitis, encephalitis, neurosyphilis
Phenylketonuria (PKU), which can cause seizures in infants
Metabolic and developmental disorders including cerebral palsy, neurofibromatosis, pyruvate dependency, tuberous sclerosis, Landau-Kleffner syndrome, and autism
Seizures can result from exposure to lead, carbon monoxide, and many other poisons. They also can result from exposure to street drugs and from overdoses of antidepressants and other medications.
Lack of sleep, stress, or hormonal changes
Withdrawal from certain antidepressant and anti-anxiety drugs
See Also: Neurophysiology Health Corner
Epilepsy in Brief
Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. These seizures are transient signs and or symptoms of abnormal, excessive or synchronous neuronal activity in the brain
Seizures in Brief
An epileptic seizure is a transient symptom of excessive or synchronous neuronal activity in the brain. It can manifest as an alteration in mental state, tonic or clonic movements, convulsions, and various other psychic symptoms
Isolated seizures can be caused by nearly any condition that affects brain function. These conditions include toxic-metabolic disturbances such as:
*- D isturbances in glucose
*- Disturbances in electrolytes
*- Renal failure
*- Drug intoxication or withdrawal
Epilepsy Vital Statistics:
Epilepsy is a chronic neurological condition characterized by recurrent seizures. It is the most common serious neurological (brain) condition. Around 10-12% of people will have a seizure during their lifetime, and 3-4% of people will be diagnosed with epilepsy at some point. While many people consider epilepsy a disease of childhood, in fact epilepsy is far commoner in people over 60 years than in people under 20 years of age.
Epilepsy can be caused by by many different conditions that affect a person’s brain. Often no definite cause can be found and it cannot be transmitted from person to person.
About 50 million people worldwide have epilepsy, with almost 90% of these people being in developing countries.