Seizures are caused by disorganized or abnormal electrical activity in the brain.
The nerve cells in the brain communicate by electrical activity, but during a seizure, too much activity disrupts normal communication.
There are many possible causes of seizures, including high fever, brain injury or tumor, street drugs, drug withdrawal, illness such as meningitis, poisoning, stroke, kidney or liver failure, and many others. If you have more than 1 seizure, you may be diagnosed as having epilepsy, meaning you are prone to seizures.
Generalized seizures involve the entire brain and include the following.
Tonic-clonic (formerly called grand mal) seizures may be preceded by sensory cues called auras. The muscles become rigid, then violently contract. A person may clench his or her teeth, become incontinent (unable to control urination or defecation), turn blue, and have trouble breathing. The person loses consciousness and afterward may be confused or sleepy.
Absence (formerly called petit mal) seizures usually involve brief staring spells, which may go unnoticed.
Atonic (drop attack) seizures cause the muscles to suddenly go limp.
Myoclonic seizures cause sudden, brief jerks of the muscles.
Partial or focal seizures involve only a part of the brain and include simple partial, in which the person remembers the seizure, and complex partial, in which the person does not recall the events. Symptoms range from unnoticeable to extremely physical and may include nausea, sweating, stomach pain, or hallucinations. Febrile seizures are caused by high fever in children.
The various types of seizures cause many symptoms ranging from brief staring spells to convulsions of the entire body and loss of consciousness. Other symptoms include briefly losing consciousness, followed by confusion; drooling; lip-smacking; unpleasant tastes or smells; mood changes; shaking; incontinence; and twitching and jerking limbs.
Medication. If you are diagnosed as having epilepsy, you will likely be prescribed 1 or more antiepileptic drugs. Drugs are helpful to many people but can have side effects, and not all seizures respond to medication. Only a few new drugs have been developed in the last 10 years.
Surgery. If medication does not control seizures, doctors may suggest surgery. Surgery works best if seizures start in a specific part of the brain.
Implanted devices. A doctor may recommend treatment such as vagus nerve stimulation or responsive neurostimulation. These involve implanting a small electronic device, similar to a pacemaker, in the body to disrupt or prevent the electrical signals that cause seizures. Another treatment, deep brain stimulation, has shown promising results but does not yet have FDA approval.
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Sources: National Library of Medicine. Epilepsy Foundation. Berg AT, Berkovic SF, Brodie MJ, et al. Epilepsia. 2010;51:676-685. Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley’s Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012: chap 67.
Sugerman DT. Seizures. JAMA. 2013;310(11):1195. doi:10.1001/jama.2013.277840