Week 4 Seizures F22 Student PDF

PATH 1017 Seizures Professor Jennifer Lamarre PATH 1017 2022-2023 1  Seizures Abnormal, uncontrolled electrical discharge (firing) from a group of neurons in the cerebral cortex Leads to an abrupt and temporary alteration in cerebral activity Considered a sym...

PATH 1017 Seizures Professor Jennifer Lamarre PATH 1017 2022-2023 1  Seizures Abnormal, uncontrolled electrical discharge (firing) from a group of neurons in the cerebral cortex Leads to an abrupt and temporary alteration in cerebral activity Considered a symptom of underlying CNS dysfunction S+S vary according to site of discharge in brain PATH 1017 2022-2023 2 Theories on Causes of Seizures Neuron membrane alterations Altered ion distribution Decreased inhibition neuron activity Structural changes Neurotransmitter imbalances PATH 1017 2022-2023 3 Seizures in Canada 1 in 100 Canadians have epilepsy First seizure typically before 20 years of age First seizure after 20 years of age typically due to structural changes, trauma, tumour, stroke May occur at any age PATH 1017 2022-2023 4 Broad Categories Unprovoked cause unknown seizures: Epilepsy secondary to the underlying Provoked cause seizures Example: HI, BT, CNS infections … PATH 1017 2022-2023 5 Focal Vs. Generalized Absence Seizures Atonic Generalized Myoclonic Seizure Tonic-clonic classification No loss of consciousness Focal Loss of PATH 1017 2022-2023 consciousness6  Focal Seizures Focal One hemisphere involved seizures Most common form of seizures in No the setting of epilepsy impairment of consciousness Sub-classified depending of effect on consciousness or awareness Impairment of consciousness PATH 1017 2022-2023 7  Focal Seizures Without Impairment Of Consciousness OR Awareness One hemisphere involved may be localized or widespread within hemisphere No loss of consciousness or responsiveness Motor, sensory, autonomic symptoms Aura What is an aura? PATH 1017 2022-2023 8  Focal Seizure With Impairment of Consciousness Or Awareness Begins in one hemisphere and rapidly spreads to the other hemisphere Typically arise on temporal lobe Impairment of consciousness and awareness May have hallucinations and illusional experiences What are automatisms? Automatisms What is a post-ictal state? Confusion post-ictually PATH 1017 2022-2023 9 Generalized Seizures Both hemispheres involved at onset Unconsciousness Motor activity is symmetrical on both sides 6 broad categories exist PATH 1017 2022-2023 10 Types of Generalized Seizures disturbances in Absence consciousness Atonic loss of muscle tone muscles strongly contract Myoclonic and jerk muscle contraction & relaxation Tonic-clonic with loss of consciousness PATH 1017 2022-2023 11 Absence Seizures Disturbance in consciousness (no convulsions) Typically children only Manifestations: Blank stare, motionless, unresponsive Motions (automatisms) Brief loss of contact with environment Lasts a few seconds, then resumes normal activities immediately PATH 1017 2022-2023 12 Atonic Seizures Sudden loss of muscle tone Manifestations: Slackening of jaw Drooping of limbs Falling to ground Risk for injury!!! PATH 1017 2022-2023 13 Myoclonic Seizure Brief involuntary muscle contractions Triggered by cerebral stimuli Manifestations: Bilateral jerking of muscles Generalized or confined to face, trunk, or one or more extremities Subtypes exist PATH 1017 2022-2023 14 Tonic-Clonic Seizures Major motor seizure May have a vague warning (focal seizure) Tonic phase: Sharp tonic contraction of muscles with extension of extremities Immediate loss of consciousness Bladder/bowel incontinence may occur Cyanosis Clonic phase: Rhythmic bilateral contraction and relaxation of extremities Unconscious until post-ictal phase –why? PATH 1017 2022-2023 15 Diagnostic Tests Neurological exam EEG Others: CT or MRI Labs to exclude other causes PATH 1017 2022-2023 16  How do anti- Treatment epileptic drugs control seizure activity? Protect from injury during seizure Reduce seizure activity: Pharmacological: Anti-epileptic drugs dependent on seizure type Examples: Phenytoin, Valproic acid Lorazepam during seizure activity Surgery may be considered if not responsive to pharmacological treatment with 2 or more drugs Neurostimulators PATH 1017 2022-2023 17 Complication: Status Epilepticus Seizures that do not stop spontaneously OR that occur in succession with out recovery Clinical or electrical seizures lasting 30 minutes or more Usually tonic-clonic type seizures A medical emergency …. Leads to respiratory failure and death if no treatment Requires life-support measures (airway!) Medications to stop seizure and control Identify underlying cause (i.e. tumour) PATH 1017 2022-2023 18 Prognosis With medications treatment: Seizures eliminated in 1/3 Frequency reduce for 50% 60% of pts who remain seizure-free can eventually stop their drugs and remain seizure- free Sudden unexplained death in epilepsy (SUDEP) is a rare complication , cause unknown PATH 1017 2022-2023 19