Signs and Symptoms

  • Seizures can vary in their outward effects
  • Symptoms range from uncontrolled shaking movements with loss of consciousness (tonic-clonic seizure) to subtle momentary loss of awareness (absence seizure)
  • Episodes usually last less than two minutes
  • Loss of bladder control may occur
  • Seizures can be provoked or unprovoked

Types of Seizures

  • Focal seizures often begin with certain experiences known as an aura
  • These experiences can include sensory, cognitive, autonomic, olfactory, or motor phenomena
  • In complex partial seizures, a person may appear confused or dazed and cannot respond to questions or direction
  • Jerking activity may start in a specific muscle group and spread to surrounding muscle groups
  • Unconscious activities known as automatisms may occur, such as smacking of the lips or attempts to pick something up
  • There are six main types of generalized seizures: tonic-clonic, tonic, clonic, myoclonic, absence, and atonic seizures
  • Generalized seizures involve a loss of consciousness and typically happen without warning
  • Tonic-clonic seizures present with limb contractions followed by shaking of the limbs
  • Tonic seizures produce constant muscle contractions
  • Clonic seizures involve shaking of the limbs in unison


  • Seizures can be caused by various factors
  • About 25% of those who have a seizure have epilepsy
  • Some seizures are acute symptomatic or provoked seizures, associated with conditions like infection, stroke, or toxicity
  • In many cases, the cause of seizures is unknown
  • Different age groups have different common causes of seizures, such as hypoxic ischemic encephalopathy in babies and febrile seizures in children.
  • Medication and drug overdoses can result in seizures.
  • Certain medications and drug withdrawal can also cause seizures.
  • Common drugs involved in seizures include antidepressants, antipsychotics, cocaine, insulin, and lidocaine.
  • Withdrawal seizures commonly occur after prolonged alcohol or sedative use, known as delirium tremens.
  • Herbal medicines such as ephedra, ginkgo biloba, and wormwood can provoke seizures in people at risk of developing epilepsy.
  • Infection with the pork tapeworm can cause neurocysticercosis, which is responsible for up to half of epilepsy cases in areas where the parasite is common.
  • Parasitic infections like cerebral malaria can also cause seizures, especially in children under five years of age.
  • Infections such as encephalitis or meningitis can lead to seizures.
  • Stress can induce seizures in people with epilepsy and is a risk factor for developing epilepsy.
  • High blood pressure, known as hypertensive encephalopathy, can cause seizures.
  • Eclampsia, a condition during pregnancy accompanied by seizures or decreased consciousness, can also lead to seizures.
  • Very high body temperatures, typically above 42°C (107.6°F), can be a cause of seizures.
  • Head injuries may result in non-epileptic post-traumatic seizures or post-traumatic epilepsy.
  • People with celiac disease have a higher prevalence of seizures (3.5 to 5.5%).

Mechanism and Tests

  • In epileptic seizures, a group of neurons fire abnormally, excessively, and synchronously due to problems within the brain.
  • This abnormal firing results in a wave of depolarization known as a paroxysmal depolarizing shift.
  • Changes in ion channels or malfunctioning inhibitory neurons can decrease the resistance of excitatory neurons to fire, leading to seizures.
  • Mutations in ion-channel genes and ion-channel abnormalities contribute to the development of epileptic seizures.
  • Seizure activity may be propagated through the brain's endogenous electrical fields, involving changes in potassium and calcium levels.
  • EEG aids in locating the focus of an epileptic seizure
  • EEG helps determine the type of seizure or syndrome present
  • EEG is recommended after a second seizure in children
  • CT scan and MRI are recommended after a first non-febrile seizure to detect structural problems in the brain
  • MRI is generally a better imaging test except when intracranial bleeding is suspected
  • Differentiating an epileptic seizure from other conditions such as syncope can be difficult
  • Conditions that can mimic a seizure include decerebrate posturing, psychogenic seizures, tetanus, dystonia, migraine headaches, and strychnine poisoning
  • 5% of people with a positive tilt table test may have seizure-like activity due to cerebral hypoxia
  • Convulsions may occur due to psychological reasons known as psychogenic non-epileptic seizures
  • Non-epileptic seizures can occur due to various other reasons

Management and History

  • Move sharp or dangerous objects away from a person experiencing a seizure
  • Place the person in the recovery position if not fully conscious and alert after the seizure
  • Seizure longer than five minutes or multiple seizures within five minutes is a medical emergency known as status epilepticus
  • Bystanders should not force objects into the mouth of a person having a seizure
  • Treatment progression for actively seizing person includes initial response, first line, second line, and third line treatments
  • First-line medication for actively seizing person is a benzodiazepine, with lorazepam being recommended
  • Diazepam and midazolam are alternatives to benzodiazepines
  • Barbiturates or propofol may be used if benzodiazepines are ineffective after two doses
  • Second-line therapy for adults is phenytoin or fosphenytoin, and phenobarbital for children
  • Third-line medications include phenytoin for children and phenobarbital for adults
  • Epileptic seizures first described in an Akkadian text from 2000 B.C.
  • Early reports saw seizures and convulsions as the work of evil spirits.
  • Ancient Greeks referred to epilepsy as the sacred disease.

Seizure Data Sources

Reference URL
Knowledge Graph