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Types of Seizure
This document classifies and defines different types of seizures. It discusses the importance of determining the seizure type to identify the cause, select appropriate treatment, and provide a prognosis. Seizures are classified as either focal or generalized. Focal seizures originate in one area of the brain, while generalized seizures involve both hemispheres. Different generalized seizures include tonic-clonic, absence, myoclonic, atonic, and others. Focal seizures can be simple, complex, or start focally and spread. The document provides detailed descriptions and diagrams of the clinical presentations and brain mechanisms of several common seizure types.
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Types of Seizure
- 1. Classification of seizure Amarendra B.Singh 090201263
- 2. 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 against Epilepsy
- 3. Definitions • Aura isthe 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.
- 4. Classification • Partial seizureoriginates from a paroxysmal discharge in a focal area of cerebral cortex (temporal lobe). * • In Primary generalized seizure the abnormal electrical discharges originate from the diencephalic activating system and spread simultaneously to all areas of brain.
- 5. Different parts havedifferent functions, and different seizures!
- 6. 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
- 7. 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
- 8. Generalized Seizures (Produced bythe 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
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- 10. Generalized Tonic ClonicSeizures
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- 16. Thalamocortical relays are believed toact on a hyperexcitable cortex A low threshold Ca2+ current Oscillatory responses in thalamic neurons Scheme of Seizure Spread
- 17. EEG: Bilaterally synchronous,high voltage 3-per-second spike-and-wave discharge pattern.
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- 21. Atonic seizure • Theseare seizure involving brief loss of muscle tone, usually resulting in heavy falls with or without loss of consciousness.
- 23. Focal Seizures (Produced bya 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
- 26. • Jacksonian March Someattacks 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.
Editor's Notes
- #3 ILAE commission has provided an updated approach to classification of seizuresThis system is based on clinical features of seizures and associated EEG findings
- #5 The Pathophysiological classification of seizure*The seizure may subsequently spread to the rest of the brain via diencephalic activating pathways. This is called as secondary generalization.
- #6 Suppose I put a device on a part of brain, that will hyperexcite & hypersynchronize an area of brain.Lets say we put it on the Primary Motor area, of the left frontal lobe. The yellow part.What will happen? Right hand seizure & may extend to right face area, lips etc.Is consciousness or awareness affected? NOWhy? Because a focal area controlling only the motor movement is affected.Now this will help us to classify.
- #8 Seizure which cannot be put into any of these two is put in unknown category
- #10 Generalized tonic-clonic seizures (formerly known as grand mal seizures) The Classical form has four phases viz. (i) aura (ii) tonic phase (iii) clonic phase (iv) post ictal phaseIn this there is abrupt loss of consciousness, and bilateral tonic extension of the trunk and limbs (tonic phase), this phase is often accompanied by a loud vocalization. as air is forcefully expelled across contracted vocal cords (epileptic cry), the respiration is arrested and central cyanosis can occur in this phase with the person turning dusky blue in colorThis is followed by synchronous muscle jerking (clonic phase).And then the post ictal phase
- #11 Generalized Tonic Clonic Seizuresare very easily recognized. The convulsions last for few minutes, Postictally, patients are briefly unarousable, then lethargic and confused, often preferring to sleep.Witnesses of a seizure are usually frightened by the event, often believe the person to be dying, and may not give clear account of the episode
- #12 The seizure starts with the person crying out, losing consciousness and falling to the ground.There is Generalized stiffening of the bodyFollowing this there are alternate periods of spasm and relaxation of musclesSo that jerking movements of the face, arm, trunk, & legs occurDuring the attack, urinary incontinence and tongue-biting may occur and the person might bleed from the mouth.After 1-3 mins seizure subsidesAfter the attack the person is confused, complains of a headache and wishes to sleep.
- #13 In tonic seizure the skeletal muscles go into sustained spasm.
- #14 Spasm of the laryngeal muscles, forces the air out from the lungs, through a partially closed glottis resulting in shrill cry.The muscular rigidity is most marked in the antigravity muscles, such as flexors of arms and extensors of lower extremeties.
- #15 Clonic seizure is characterized by rhythmic alternating contractions of muscle groups,Which persists for few minutes
- #16 Absence Seizures (also k/a Petit mal)Absence seizures are often described as staring spells. The person stops what he or she is doing and stares vacantly for a few seconds, then continues as if nothing happened. The seizure lasts less than 30 seconds.This type of seizure is more common in children and usually starts between the ages of 4 and 12. Some children experience up to 100 absence seizures in a day. Absence seizure are not associated with post-ictal confusion.
- #17 This is important to know because the drugs Ethosuximide and valproate act on thalamic ca+ channels.It will be dealt with the next speaker.
- #18 Electro-encephalogram shows a characteristic 3 per second spike and slow wave pattern.
- #19 The person shows sudden discontinuation of the activity being performed with staring spell, rapidly blinking eyes.As you can see there is no loss of posture, no urinary incontinence or breathing difficulty.Other neurological manifestations and post ictal phenomena are absent. And the person can resume normal work soon after the seizure.Reassurance is important.
- #20 Myoclonic seizures are characterized by rapid, brief ,shock like muscle jerks that can occur bilaterallyor unilaterally.Myoclonic jerks range from isolated small movements of face, arm, or leg muscles to massive bilateral spasms simultaneously affecting the head, limbs, and trunk.West syndrome (onset 3-8 months)Lennox-gastaut syndrome (onset late infancy or childhood)
- #21 Myoclonic seizure in a sleeping child
- #22 As the name tells… Atonic seizure areIn this the patient loses tone suddenly and falls down like a lump.
- #24 3. Symptoms that are initially associated with a preservation of consciousness that then evolves into a loss of consciousness and convulsions.
- #25 Epileptic activity arising in the pre-central gyrus causes partial motor seizures,affecting the contralateral face, arm, trunk or leg.There is sustained spasm or rhythmical jerking of the affected parts.Seizure arising in the sensory cortex, cause unpleasant tingling or ‘electric sensations’ in the contralateral face or limbs.
- #26 Types of partial seizures Motor – focal motor activity, Jacksonian march, versive movements (turning of the eyes, head and/or trunk), vocalizations or arrest of speech Sensory – paresthesias, feelings of distortion of an extremity, gustatory sensation, olfactory symptom, auditory symptoms, visual phenomena (flashing lights) Autonomic seizures – sweating, piloerection, papillary changes, epigastric “rising” sensation Psychic symptoms – dysphagia, cognitive, déjà-vu (dysmnestic), unreality (jamais vu) affective, illusions, hallucinations
- #29 Complex partial seizure was formerly known as temporal lobe seizure.Only a Part of the brain is affected and consciousness is impaired.Some people experience aura-Like strange burnt rubber or gasoline smellOr epigastric rising sensationPerson stops what they are doing and stare blankly, making smacking lip movements,Or displaying other automatisms, such as pricking at their clothes, wandering around.People mistakenly confuse this type of seizure with drunkeness or drug overdose.Seizure lasts for 2-4 mins.Person is unable to recall the seizure events later on and is confused.