Epileptic seizure | |
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Other names | Epileptic fit,[1] seizure, fit, convulsions[2] |
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Generalized 3 Hz spike and wave discharges in an electroencephalogram (EEG) of a patient with epilepsy | |
Specialty | Neurology, emergency medicine |
Symptoms | Variable[3] |
Complications | Falling, drowning, car accidents, pregnancy complications, emotional health issues[4] |
Duration | Typically < 2 minutes[5] |
Types | Focal, generalized; Provoked, unprovoked[6] |
Causes | Provoked: Low blood sugar, alcohol withdrawal, low blood sodium, fever, brain infection, traumatic brain injury[3][6] Unprovoked: Unknown, brain injury, brain tumor, previous stroke[5][3][6][7] |
Diagnostic method | Based on symptoms, blood tests, medical imaging, electroencephalography[7] |
Differential diagnosis | Syncope, psychogenic non-epileptic seizure, migraine aura, transient ischemic attack[3][5] |
Treatment | Less than 5 min: Place person on their side, remove nearby dangerous objects[8] More than 5 min: Treat as per status epilepticus[8] |
Frequency | ~10% of people (overall worldwide lifetime risk)[5][9] |
A seizure is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain.[6] Outward effects vary from uncontrolled shaking movements involving much of the body with loss of consciousness (tonic-clonic seizure), to shaking movements involving only part of the body with variable levels of consciousness (focal seizure), to a subtle momentary loss of awareness (absence seizure).[3] These episodes usually last less than two minutes and it takes some time to return to normal.[5][8] Loss of bladder control may occur.[3]
Seizures may be provoked and unprovoked.[6] Provoked seizures are due to a temporary event such as low blood sugar, alcohol withdrawal, abusing alcohol together with prescription medication, low blood sodium, fever, brain infection, flashing images or concussion.[3][6] Unprovoked seizures occur without a known or fixable cause such that ongoing seizures are likely.[5][3][6][7] Unprovoked seizures may be exacerbated by stress or sleep deprivation.[3] Epilepsy describes a brain disorder in which there has been at least one unprovoked seizure and where there is a high risk of additional seizures in the future.[6] Conditions that look like epileptic seizures but are not include: fainting, nonepileptic psychogenic seizure and tremor.[3]
A seizure that lasts for more than a brief period is a medical emergency.[10] Any seizure lasting longer than five minutes should be treated as status epilepticus.[8] A first seizure generally does not require long-term treatment with anti-seizure medications unless a specific problem is found on electroencephalogram (EEG) or brain imaging.[7] Typically it is safe to complete the work-up following a single seizure as an outpatient.[3] In many, with what appears to be a first seizure, other minor seizures have previously occurred.[11]
Up to 10% of people have had at least one epileptic seizure in their lifetime.[5][9] Provoked seizures occur in about 3.5 per 10,000 people a year while unprovoked seizures occur in about 4.2 per 10,000 people a year.[5] After one seizure, the chance of experiencing a second one is about 40%.[12][13] Epilepsy affects about 1% of the population at any given time.[9]
Any animal that has a brain can have a seizure.[14]
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