is a chronic condition produced by temporary changes in the electrical function of the brain, causing seizures, which can affect awareness, movement, or sensation.
Seizures occur when clusters of nerve cells in the brain, called neurons, signal or communicate with each other abnormally. During a seizure, the neurons' normal pattern of activity is disturbed. It causes them to fire as many as 500 times per second instead of the normal rate of about 80 times per second. This can cause strange sensations, emotions, and behavior, or convulsions, muscle spasms, and/or loss of consciousness.
Neurons in Nerve Tissue
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A diagnosis of epilepsy is usually not made until a person has a seizure more than once without a preventable cause.
The causes of abnormal brain wiring and imbalance of neurotransmitters are numerous. They can include:
- Head injury
- Brain abnormalities inherited at birth
- Gene abnormalities inherited at birth
- Brain injury at birth
- Loss of neurons in the hippocampus, also called mesial temporal sclerosis
- Brain tumors
Metabolic conditions, such as
low blood sugar, very high blood sugar, low calcium, high or low sodium, or low magnesium
- Alzheimer's disease
- Heart failure
- Liver failure
- Kidney failure
- Sickle cell anemia
Vasculitis, such as
systemic lupus erythematous
Any condition that deprives the brain of oxygen, such as
Infectious diseases, such as:
—excess fluid in the brain
- Celiac disease
—intolerance to wheat gluten
drugs, such as
cocaine, amphetamines, phencylidine
- Overdose of antidepressants and other medicines
alcohol, sedatives, and hypnotics
Certain medicines can lower the seizure threshold and thus increase the risk of seizures, such as:
- High fever
- Maternal infections
- Poor nutrition
- Lead poisoning
deficiency in neonates, infants
- Hereditary, including genetic syndromes and metabolic disorders
In many cases, the exact cause of epilepsy is not known.
The Merck Manual of Medical Information. 17th ed. New York, NY: Simon and Schuster; 2000.
Epilepsy in adults. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed. Updated February 18, 2013. Accessed February 22, 2013.
Epilepsy in children. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed. Updated November 19, 2012. Accessed February 22, 2013.
Lowenstein DH. Seizures and epilepsy. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J, eds.
Harrison's Principles of Internal Medicine.
18th ed. New York, NY: McGraw-Hill; 2012.
NINDS Epilepsy information page. National Institute of Neurological Disorders and Stroke website. Available at:
http://www.ninds.nih.gov/disorders/epilepsy/epilepsy.htm. Updated February 21, 2013. Accessed February 22, 2013.
What is epilepsy? Epilepsy Foundation
website. Available at:
http://www.epilepsyfoundation.org/aboutepilepsy/whatisepilepsy/index.cfm. Accessed February 22, 2013.
Last reviewed March 2013 by Rimas Lukas, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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