This page compiles our content related to seizure disorder. For further information on diagnosis and treatment, follow the links below to our full BMJ Best Practice topics on the relevant conditions and symptoms.
A seizure is defined as "a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain". Epilepsy is considered to be a disease of the brain defined by any of the following conditions: ILAE: EpilepsyDiagnosis.org Opens in new window
At least two unprovoked (or reflex) seizures occurring more than 24 hours apart
One unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years
Diagnosis of an epilepsy syndrome.
Epileptic seizures may be classified as focal, generalized, or unknown onset, with subcategories of motor, non-motor (absence), with retained or impaired awareness for focal seizures.
go to our full topic on Status epilepticus
A life-threatening neurologic condition defined as 5 or more minutes of either continuous seizure activity or repetitive seizures without regaining consciousness. Generalized convulsive status epilepticus in both its subtle and overt subtypes constitutes the most frequent variant. Recognition is crucial because rapid termination helps prevent serious brain injury, especially in patients with impaired consciousness. Treatment involves a stepwise medication approach aimed at aborting the clinical and electrographic seizures.
go to our full topic on Generalized seizures in adults
Generalized seizures (generalized tonic-clonic seizures [GTCS]) classically involve loss of consciousness and a phasic tonic stiffening of the limbs, followed by repetitive clonic jerking. Most GTCS are self-limiting without intervention. The electroencephalogram shows bisynchronous epileptiform activity in both cerebral hemispheres. GTCS occur in many different types of epilepsy. Anti-epileptic agents are the primary treatment for all types. GTCS may also be provoked by an insult in an individual who does not have epilepsy.
go to our full topic on Generalized seizures in children
Seizures may occur as a stand-alone event or may be recurrent. Risk factors include a past medical history of perinatal insult (e.g., asphyxia) or febrile seizures; a genetic predisposition or family history; neurodegenerative disorders; infection; metabolic or immune disorders; head trauma; and structural abnormalities of the central nervous system. EEG is the standard diagnostic test, and brain CT or MRI may also be helpful. The main treatment options will depend on the epilepsy syndrome but include anticonvulsants, a ketogenic diet, vagus nerve stimulation, or lifestyle measures.
go to our full topic on Febrile seizures
Seizures occurring in a febrile child, between the ages of 6 and 60 months, without evidence of intracranial infection, metabolic disturbance, or history of afebrile seizures. The diagnosis is made by clinical assessment, with lumbar puncture performed to exclude meningitis or encephalitis if suspicion exists. Most febrile seizures resolve spontaneously and do not require acute or long-term anticonvulsant treatment.
go to our full topic on Absence seizures
Typically characterized by abrupt cessation of activity and responsiveness, lasting between 5 to 10 seconds, with minimal associated movements, staring episodes, and no aura/postictal state. Typical absence seizures may be precipitated by hyperventilation and photic stimulation. EEG is the definitive test. Most typical absence seizures are medically responsive, and childhood absence epilepsy (CAE) tends to remit by adulthood. Typical absence seizures in CAE, juvenile absence epilepsy, and juvenile myoclonic epilepsy are treated with anticonvulsants. Atypical absence seizures have a less distinct begninning and end, and are not usually precipitated by hyperventilation. Atypical abscence seizures tend to be medically refractory and associated with cognitive impairment.
go to our full topic on Focal seizures
Focal (partial) seizures are the electrical and clinical manifestations of seizures that arise from one portion of the brain. They may occur in the context of an underlying structural brain abnormality, or may be idiopathic. The EEG typically indicates a localized discharge over the area of onset. The temporal lobe is the most common area of onset for focal seizures, but they may arise from any lobe. Consciousness is preserved in focal aware seizures, whereas focal impaired awareness seizures feature memory loss for the duration of the clinical event or impaired responsiveness at the time of the event. Focal seizures may lead to secondary generalized seizures. Monotherapy with antiepileptic medication is the preferred initial treatment.
go to our full topic on Infantile spasms
An epilepsy syndrome typically presenting in infancy, with a varying etiology. Spasms may be flexor, extensor, mixed flexor-extensor, symmetrical or asymmetrical, and typically occur in clusters. A hypsarrhythmic pattern on EEG is characteristic, but not universally present at all times. Infantile spasms are often associated with an underlying disorder. Where no underlying cause is detected (10% to 40% of patients) and there is normal development prior to onset, the prognosis tends to be better. Treatment options include hormonal therapy (adrenocorticotropic hormone or corticosteroids) or vigabatrin.
go to our full topic on Evaluation of syncope
Differentiating between syncope and epileptic seizures can sometimes be challenging. Twitching and jerking are often seen with vasovagal or cardiac syncope, which can be differentiated from rhythmic jerking of all the limbs in tonic-clonic seizures. Loss of bowel and bladder control, commonly seen with seizures, is rare during syncope. Postictal confusion is one of the key differentiating factors for seizures. The presence of an aura and unconsciousness for >5 minutes is more typical of a seizure.
BMJ Publishing Group
This overview has been compiled using the information in existing sub-topics.
Epilepsy: questions to ask your doctorMore Patient leaflets
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