seizure
(sē'zhŭr 
)
- A convulsion or other clinically detectable event caused by a sudden discharge of electrical activity in the brain.
- A sudden attack of pain, disease, or specific symptoms.
absence s.Seizure in which there is a sudden, brief lapse of consciousness, usually for about 2 to 10 sec. The patient resumes activity as if the seizure had not occurred. The seizure may be induced by voluntary hyperventilation for 2 to 3 min. This type of attack is characteristic of petit mal epilepsy and may recur repeatedly if it is not recognized and treated. It also may progress to a generalized tonic-clonic seizure.
The patient (typically a child) shows a blank facial expression that may be accompanied by movements such as repeated blinking or rolling of the eyes, or lip smacking and minor myoclonus of the upper extremities or neck. There is no convulsion or fall.
The only diagnostic test for absence seizures is an electroencephalogram. Brain scans, as by an magnetic resonance imaging, can help rule out other diseases, e.g., stroke or a brain tumor.
Treatment with valproate or other anticonvulsants is effective for controlling absence seizures in approx. 75% of patients.
The time, duration, patient's expression, and any repetitive movements occurring during the seizure are observed and documented, as is the patient's postseizure response. Prescribed medications are administered and evaluated for desired effects and adverse reactions. Support, reassurance, and education regarding the condition as well as drug actions and side effects are provided to the patient and family, and they are encouraged to discuss their feelings and concerns and to ask questions.
SEE: epilepsy.
acute symptomatic s.A seizure that results either from abnormal metabolic conditions that affect normal brain function or toxic exposures (such as alcohol or drug withdrawal, electrolyte disturbances, overwhelming infections, or toxins) or from structural lesions in the brain (such as brain trauma or central nervous system masses). SYN: provoked seizure.
breakthrough s.A seizure that occurs despite the use of therapeutic concentrations of a previously effective antiepileptic drug.
complex s.A seizure in which the patient suffers a loss of consciousness.
convulsive s.1A convulsion.2An attack of epilepsy.
SEE: epilepsy.
dissociative s.A psychogenic, non-epileptic seizure, i.e., a pseudo seizure.
drop s.Complete loss of muscle strength during a seizure. It can result in sudden falls and serious injuries. Also known as: akinetic seizure or atonic seizure.
dyscognitive s.Focal impaired awareness seizure.
febrile s.A seizure that lasts less than 15 min and that occurs when a child between the ages of 6 months and 5 years has an elevated temperature but no other signs of infection in the brain, spinal cord or meninges.
About 5% of all children will experience febrile seizures.
The seizure typically accompanies a bacterial or viral infection (such as otitis, pharyngitis, or sinusitis). Recent vaccination with tetanus or with measles, mumps, and rubella vaccines increase the likelihood of febrile seizures. Some children may be genetically predisposed to the condition. Some evidence links iron deficiency to febrile seizures as well.
Most children will have a generalized, tonic-clonic seizure. To qualify as a febrile seizure, the event must last less than 15 min and not have any associated signs of meningeal irritation. Febrile seizures are benign. In the vast majority of patients they do not result in any lasting impairments.
Laboratory studies are not generally needed, and most experts, e.g., the American Academy of Pediatrics (APA), recommend against the use of brain imaging or electroencephalography in evaluating children with febrile seizures. Lumbar puncture should be performed only when a child has evidence of meningeal irritation on physical examination or a predisposing condition, such as an immune deficiency, that might increase the likelihood of meningitis.
Anticonvulsants such as lorazepam or fosphenytoin administered in the Emergency Department control febrile seizures, but most experts do not recommend chronic prescription of antiepileptic drugs to children with febrile seizures after a single episode even though the risk of recurrent seizures in these children is higher than in the general population.
The likelihood of serious bacterial infection or meningitis associated with a simple febrile seizure in a child who otherwise appears healthy is low. The risk of recurrent febrile seizures after an initial event is 30% to 35%. Administration of acetaminophen to reduce fever in patients who have previously had a febrile seizure has not been definitively shown to reduce the risk of recurrence.
Children with a prolonged febrile seizure or children with focal neurological deficits associated with a seizure require close evaluation and treatment, including attention to ABC (airway, breathing, circulation) and neurological deficits.
Observing a child undergoing a seizure is emotionally troubling for parents and siblings. The APA recommends education of the patient, emotional support, and follow-up for patients and family members.
focal aware s.A seizure in which people maintain consciousness of themselves and their surroundings. Formerly known as simple partial seizure.
focal impaired awareness s.A focal seizure in which people lose consciousness of themselves or their surroundings. Formerly known as complex partial seizure.
focal non-motor s.A focal seizure in which people experience abnormal sensations, thoughts, or feelings but do not have abnormal body movements.
focal unaware s.Complex partial seizure.
generalized non-motor s.A seizure in which people become unaware of themselves or their surroundings but do not stiffen or jerk their arms or legs. Formerly known as petit mal seizures.
generalized s.A seizure in which abnormal electrical activity occurs in large areas of the brain. Generalized seizures usually result in loss of consciousness.
SEE: under epilepsy.
jacksonian s.A localized form of epilepsy with spasms confined to one part or one group of muscles.
SEE: epilepsy.
nonepileptic s.A seizure often accompanied by loss of consciousness, due to inadequate perfusion of the brain, e.g., during a sudden lowering of blood pressure or, in treated diabetic patients, from hypoglycemia.
SEE: epilepsy.
provoked s.Acute symptomatic seizure.
ABBR: PNES
Pseudoseizure.reflex s.A seizure that reliably occurs in response to an external stimulus, such as exposure to bright lights.
simple s.A seizure in which there is no loss of consciousness.
subclinical s.A seizure that shows no accompanying clinical signs or symptoms but is detected only by an electroencephalogram.
uncinate s.A seizure marked by olfactory and gustatory hallucinations (usually disagreeable), a sense of unreality, and sometimes convulsions and temporary loss of senses of taste and smell. This is associated with lesions of the uncinate gyrus of the temporal lobe of the brain.
unprovoked s.A seizure that occurs without a clinically obvious stressor (such as a high fever or an overdose of insulin). Unprovoked seizures are more likely than acute symptomatic (provoked) seizures to be linked to structural or functional abnormalities in the brain.