Symptoms vary according to how much of the brain is affected Table 01. Generalized seizures involve the entire brain, and are associated with loss of consciousness. Generalized seizures are classified as: tonic-clonic seizures (previously called grand mal seizures), absence seizures (previously called petit mal seizures), tonic seizures, clonic seizures, myoclonic seizures, and atonic seizures.
A person having a grand mal seizure will fall down, become stiff, temporarily stop breathing, and start to jerk all over (convulse). This type of seizure starts with brief sustained muscular contraction during which the legs and arms extend or flex (the tonic phase). This activity progresses to rhythmic contractions of the limbs that gradually decrease in frequency (the clonic phase). Bladder and bowel control are sometimes lost. The entire event may last a few minutes, after which the patient will be disoriented and tired, and will have no recollection of the seizure. Some may experience the tonic phase or the clonic phase exclusively.
A person having a myoclonic seizure will suffer a violent bodily jolt. This will sometimes manifest as suddenly dropping or involuntarily throwing objects.
Absence seizures are characterized by a brief loss of consciousness. People with absence seizures (also called petit mal seizures) will typically stare blankly for a few seconds before regaining consciousness. If untreated, the syndrome can occur many times throughout the day.
Atonic seizures (drop attacks) involve a loss of bodily control and a fall to the ground that may injure the head or body.
Unlike grand mal seizures, however, atonic seizures are not associated with convulsions or arrested breathing.
Partial (focal) seizures involve just one brain region, and are not associated with a loss of consciousness. Partial seizures can be either simple or complex. Depending on which part of the brain is affected, a simple partial seizure can manifest as jerking in a body part or sensing abnormal smells.
In a complex partial seizure, consciousness is altered. The patient may stare blankly or exhibit random behavior (automatisms) such as chewing, lip-smacking, or hand-wringing. While the blank stare symptom is also characteristic of an absence seizure, complex partial seizures last longer, occur less frequently, and are usually associated with automatisms.
Table 1. Epilepsy Syndromes
Seizure disorder Age of onset Type of seizure West syndrome 6-24 months Infantile spasms Lennox-Gastaut syndrome 2-5 years Tonic, atonic, atypical absence Benign childhood epilepsy 5-10 years Simple partial, complex partial Childhood absence epilepsy 4-10 years Absence, generalized tonic-clonic Juvenile absence epilepsy 10-17 years Absence, generalized tonic-clonic Juvenile myoclonic epilepsy 12-18 years Myoclonic, generalized tonic-clonic Temporal lobe epilepsy 10-30 years Complex partial Nocturnal frontal lobe epilepsy 5-20 years Frontal lobe complex partial
Although seizure disorders afflict people of all ages, they are most common in younger age groups. Epilepsy affects about 3% of the U.S. population. Some types of epilepsy manifest only in childhood. For example, West syndrome, which is marked by infantile spasms (also called salaam attacks), usually appears before the first birthday.
Although not considered epilepsy, fever-induced generalized tonic-clonic seizures (febrile seizures) occur in one out of every 100 children, usually between the ages of 3 months and 5 years. The seizure may occur when the child's temperature is rising or coming down.
Some seizure disorders, such as juvenile absence epilepsy and juvenile myoclonic epilepsy, emerge during adolescence. Both appear to have a strong genetic link.
Epilepsy is common in the elderly. The increased incidence of epilepsy in the elderly is due, in part, to the higher incidence of stroke in this age group. In addition, the elderly are more likely to experience events such as head trauma from falls, which can also lead to seizures. Temporal lobe epilepsy is the most commonly diagnosed seizure disorder in adults, but it typically begins during young adulthood and not in the elderly. Some people with this syndrome may have had fever-induced seizures in their youth, but the complex partial seizures don't show up until early adulthood.
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