See epilepsy
A seizure is a brief excessive discharge of electrical activity in the brain that transiently alters behavior.
Neurons communicate by chemical and electrical signals forming networks with other neurons and in most seizures a relatively small number of abnormal neurons cause changes in other neighboring or network neurons.
During a seizure there is a progressive recruitment of other neurons that results in hypersynchrony.
This abnormal provocation is a result of insufficient inhibition, or excessive excitation within the neural network.
Abnormal neuronal hypersynchrony can be a congenital or an acquired process.
Recurrent seizures affect 2-4 million persons in the U.S.
Prevalence highest in people under the age of 20 years.
One in 10 adults will have a seizure in their lifetime.
The incidence of a single unprovoked seizure among adults is 23-61 cases per hundred thousand person years.
Between 21 and 45% of adults with seizures will have a second seizure within two years, but more than half never have another episode.
Acute seizures account for 1% of adult and 2% of pediatric emergency department visits.
Fewer than 1% of US children and teens have has at least one seizure.
US children and teens in US who have had a seizure are more economically disadvantage and more likely to have developmental delays than those who are seizures free.
Incidence increases over the age of 70 years to more than 100 cases per 100,000.
Cumulative incidence is thought to be almost 10% to age 74 years.
Lifetime likelihood of having a diagnosis of epilepsy is almost 3%.
Transient loss of consciousness with spontaneous recovery may be related to seizures.
Seizures are a constellation of symptoms related to a transient episode of abnormal excessive synchronous neuronal activity in the brain.
Seizures are classified based on the appearance of the seizure and parts of the cerebral cortex involved in the seizure.
Classification of seizures has important consequences for determining the etiology , treatment, and overall prognosis.of the cerebral cortex involved in the seizure.
Classification of seizures has important consequences for determining the etiology , treatment, and overall prognosis.
There two main types of seizure onset, focal and generalized.
Over forty types of epilepsy are recognized and these are divided into two main groups: focal seizures and generalized seizures.
Primary generalized seizures involve bilaterality distributed networks at onset.
Focal seizures account for approximately sixty percent of all adult cases.
Temporal lobe epilepsy (TLE) is the single most common form of focal seizure.
During focal seizures, awareness may be preserved or lost.
Focal seizures may be associated with motor or non-motor aspects.
Motor features of focal seizures include tonic, clonic or hyperkinetic activity.
Focal seizures are a small group of neurons within enhanced excitability and occasionally the ability to spread to neighboring regions and cause a seizure.
Seizures can begin in any lobe of the brain, but is most common at the temporal lobe, particularly the mesial temporal lobe containing the amygdala and hippocampus.
Clinical manifestations of focal seizures depend on the normal function of the region of cortex involved in the seizure.
Non-motor signs of focal seizures include behavioral and cognitive changes, autonomic or emotional changes as well.
During a focal aware seizure individuals are able to respond and remembers the seizure.
A focal aware seizure is synonymous with an aura.
Generalized seizures can present with motor and or non-motor features.
Motor features associated with generalized seizures include tonic-clonic, myoclonic, or other types of motor activity.
Tonic-clonic seizures are commonly referred to as convulsions or grand mal seizures begin with loss of consciousness.
The tonic phase can lead to falls and an epileptic cry caused by Air forced through contracted vocal cords.
The cloniv phase consists of jerking of the upper and lower extremities with associated cyanosis, tongue biting, and foaming of the mouth and incontinence.
Following the tonic-clonic seizure, the patient is lethargic and confused and may become agitated as consciousness is regained.
Generalized seizure non-motor features include staring spells, drop attacks, and eyelid myoclonus.
Myoclonic seizures are very quick shock-like jerks of a muscle or group of muscles and typically involve the upper extremities without altered level of awareness.
Cyanosis may appear during a generalized seizure due to respiratory inhibition.
Tongue injury may occur with generalized seizures during tonic contraction of the jaw.
Patients with generalized seizure may have prolong confusion, that is postictal confusion.
Some forms of epilepsy can be classified as an epilepsy syndrome, which are types of epilepsy in which clear demographic seizure type, EEG pattern, and prognosis or known.
Evaluation of the patient with the first seizure may include an EEG, CT or magnetic resonance imaging of the brain, blood tests, lumbar puncture, toxicology, physical examination, and history.
Approximately 150,000 US adults experience a first unprovoked seizure annually.
All individuals have a seizure threshold and could potentially experience a seizure.
Lifelong prevalence of experiencing a single seizure is approximately 10%, but approximately 30% can have recurrent seizures and experience epilepsy.
Most are a provocation of a systemic process or intrinsic brain process.
The risk of seizure recurrence doubles in patients with a head injury, stroke, or brain tumor.
Provoked seizures that occur in the immediate aftermath of a stroke, head injury, or low blood glucose have a low risk of recurrent seizures.
Seizure related injuries and accidents are most often associated with generalized tonic-clonic seizures, amf up to 25% of people with such disorders have had at least one severe injury in their lifetime.
Common causes of provoked seizures are: alcohol intoxication, alcohol withdrawal, amphetamine use, cocaine use, LSD use, phencyclidine, use of high-dose penicillin intravenously, imipenem use, anti-arrhythmic drugs lidocaine, procainamide and propafenone, insulin excess, opiates, especially Demerol tramadol, antidepressants clomipratine and Bupropion, antipsychotic agents such as clozapine, mixed amphetamine stimulants, brain abscess, cerebritis, from infectious agents, encephalitis from cytomegalovirus, herpes simplex virus type 1, Varicella-zoster virus, West Nile virus, acute meningitis with bacterial and fungal or viral agents, hypocalcemia, hypoglycemia, hyperglycemia, hypomagnesemia, hyponatremia, hypernatremia and hyperphosphatemia.
Almost all users in adults cease in less than 5 min. without treatment, and seizures less than longer than this are more likely to be self sustained and to require intervention.
In most cases provoked seizures will not recur if the provoking factor is corrected.
Starting medication immediately after a first seizure reduces the chances of having another one by more than one third within the next two years.
Seizure medicines carry a risk of adverse events ranging from 7-31%.
The longer seizures persist the harder they are to terminate pharmacologically.
Recurrent seizures is referred to as epilepsy.
Can cause direct injury to the brain, and via indirect effects such as sleep deprivation, social stigma and impairment of interpersonal relationships can increase patient’s risk for emotional disturbances.
Recurrent seizures are associated with seizure related injuries in approximately 28 to 40% of patients and the mortality rate that is 1.6 to 9.3 times higher than the general population during the first two years of after diagnosis.
Causes of death of typically drowning, suicide, status epilepticus, or a sudden unexpected death.
The incidence of sudden unexpected death in epilepsy is approximately 0.35 cases per thousand person years in patients with a new diagnosed disease, and the incidence increases to approximately 1to 6 per 1000 person years with chronic epilepsy and 6 to 9 per 1000 person years in patients with treatment resistant epilepsy.
Generalized tonic-clonic seizures are the strongest risk factor for sudden, unexpected, death and epilepsy, the leading cause of epilepsy related death.
The average risk of sudden, unexpected death for a person living with epilepsy is 1% per decade.
Each year sudden, unexpected death claims one in1000 lives among people with epilepsy, and the risk is one in 250 for those with severe forms of epilepsy.
The risk of death increases with the frequency of generalized tonic-clonic-seizures, and living alone increases the risk of sudden death, especially with tonic-clonic seizures.
Approximately 1.5% of older Americans require antiseizure medications.
The likelihood of brain tumors among adults with new-onset epilepsy is approximately 12% and is highest among the elderly.
Presenting feature in 2-33% of patients with ischemic stroke and common in intracerebral hemorrhage, venous sinus thrombosis, and hypertensive encephalopathy.
EEG should be performed 48 hours or more after a suspected seizure, because obtaining one shortly after a seizure may yield misleading results.
A single EEG will show no abnormalities in approximately 50% of patients.
Approximately 10% of persons with true seizures have multiple normal EEG’s.
More frequent in Alzheimer’s disease and patients with epilepsy have a greater risk of developing Alzheimer’s disease.
More common in depressed individuals and patients with seizures are more likely to be depressed.
In most states 3-12 month seizure-free intervals are required before patients can legally drive.
Temporal lobe epilepsy most common cause of anticonvulsant drug therapy resistance.
Effective early management may improve the likelihood of long-term success in controlling epilepsy.
Children may be particularly likely to benefit from epilepsy surgery, according to a study of 18 children with bilateral epileptic foci who underwent surgery for palliation: At a median follow-up of 1.4 years, 44% had no seizures,on medications, and 17% had more than 50% reduction in seizure frequency.
A retrospective study involving children with intractable epilepsy reported that 52% experienced more than 50% reduction in seizure frequency with cannabis.
Ephedra, St. John’s wort, ginkgo biloba, caffeine, creatine, star anise, star fruit, and evening primrose have been associated with seizures.