Classification of seizure Amarendra B. Singh 090201263
Classification of seizure It is important to determine the type of seizure that has occurred – to find out the etiology , selecting the appropriate therapy and providing information regarding prognosis ILAE- International League a gainst Epilepsy
Definitions Aura is the subjective sensation or phenomenon that precedes and marks the onset of the epileptic seizure - it may localize the seizure origin within the brain . Ictus is the attack or seizure itself . Postictal period is the time after the ictus during which the patient may be drowsy, confused, and disoriented.
Classification Partial seizure originates from a paroxysmal discharge in a focal area of cerebral cortex (temporal lobe). * In P rimary generalized seizure the abnormal electrical discharges originate from the diencephalic activating system and spread simultaneously to all areas of brain.
Different parts have different functions, and different seizures!
Classifying Seizures Focal (previously ‘partial’) seizure – initial activation of only part of one cerebral hemisphere occurs. (although may generalize*) Generalized seizure – discharge from both cerebral hemispheres occurs. Loss of consciousness may occur. Seizure types: Partial Generalized Simple Complex Absence Convulsive Consciousness is maintained Consciousness is lost or impaired Altered awareness Characterized by muscle contractions with or without loss of consciousness
I. Generalized seizures Tonic Clonic Tonic – clonic Absence (typical / atypical) Myoclonic Atonic II. Focal seizures 1. Simple Motor Sensory Autonomic 2. Complex (temporal lobe or frontal lobe) 3. Focal seizure with secondary generalization III. Unknown Epileptic spasms
Generalized Seizures (Produced by the entire brain) Symptoms 1. "Grand Mal" or Generalized tonic-clonic Unconsciousness, muscle rigidity, convulsions . 2. Absence Brief loss of consciousness 3. Myoclonic Sporadic (isolated), jerking movements 4. Clonic Repetitive jerking movements 5. Tonic Muscle stiffness, rigidity 6. Atonic Loss of muscle tone
Generalized Tonic Clonic Seizures
Generalized Tonic Clonic Seizures
Tonic seizure
Clonic seizure
Absence seizures
Thalamocortical relays are believed to act on a hyperexcitable cortex A low threshold Ca 2+ current Oscillatory responses in thalamic neurons Scheme of Seizure Spread
EEG: Bilaterally synchronous, high voltage 3-per-second spike-and-wave discharge pattern.
Myoclonic seizure
Myoclonic seizure
Atonic seizure These are seizure involving brief loss of muscle tone, usually resulting in heavy falls with or without loss of consciousness.
Focal Seizures (Produced by a small area of the brain ) Symptoms 1. Simple (awareness is retained) a. Simple Motor b. Simple Sensory c. Simple Autonomic a . Jerking, muscle rigidity, spasms, head-turning b. Unusual sensations affecting either the vision, hearing, smell, taste, or touch c. Memory or emotional disturbances 2. Complex (Impairment of awareness) Automatisms such as lip smacking, chewing, fidgeting, walking and other repetitive, involuntary but coordinated movements 3. Focal seizure with secondary generalization
Jacksonian March Some attacks begin in one part of the body (e.g. mouth, thumb, great toe) and spread (march)gradually towards other parts of the body. Attacks vary in duration from few seconds to several hours ( epilepsia partialis continua ) Todd’s palsy is paresis of the involved limb lasting for several hours after the seizure ceases.