Epilepsy Epilepsy

11

Seizures Seizures

A seizure is as a sudden, disorderly discharge of A seizure is as a sudden, disorderly discharge of cerebral neurons. cerebral neurons.

Seizures involve a Seizures involve a transient alteration in transient alteration in brain function brain function (motor, sensory, (motor, sensory, autonomic, or autonomic, or psychic clinical psychic clinical manifestations)manifestations)

22

DefinitionDefinition

A A chronic neurologic disorderchronic neurologic disorder manifesting by manifesting by repeated epileptic seizures repeated epileptic seizures (attacks or fits) which (attacks or fits) which result from result from uncontrolled discharges of neurons uncontrolled discharges of neurons within the central nervous systemwithin the central nervous system

The clinical manifestations The clinical manifestations rangerange fromfrom a major a major motor convulsion to a brief period of lack of motor convulsion to a brief period of lack of awareness. The uncontrollable nature of the attacks awareness. The uncontrollable nature of the attacks is characteristic of epilepsy.is characteristic of epilepsy.

33

Epidemiology and Epidemiology and coursecourse5% of the population suffer a single sz at some 5% of the population suffer a single sz at some

timetime0.5-1% of the population have recurrent sz = 0.5-1% of the population have recurrent sz =

EPILEPSYEPILEPSY70% = well controlled with drugs (prolonged 70% = well controlled with drugs (prolonged

remissions)remissions)30% epilepsy at least partially resistant to drug 30% epilepsy at least partially resistant to drug

treatmentstreatments

44

Types of Seizures Types of Seizures

Seizures can be classified as either partial or Seizures can be classified as either partial or generalizedgeneralized

The type of seizure as well as the signs and The type of seizure as well as the signs and symptoms that accompany the seizure depend on the symptoms that accompany the seizure depend on the

part of the brain in which the seizures occurpart of the brain in which the seizures occur

55

Types of Seizures - Types of Seizures - PartialPartial

Partial Seizures are seizures that begin locally (in Partial Seizures are seizures that begin locally (in one part of the brain)one part of the brain)

i.i. Simple Partial seizureSimple Partial seizure (consciousness not (consciousness not impaired)impaired)

ii.ii. Complex partial seizureComplex partial seizure (consciousness (consciousness impaired)impaired)

iii.iii. Secondary generalized seizureSecondary generalized seizure (begins as (begins as partial and transitions into a generalized partial and transitions into a generalized seizure)seizure)

66

Types of Seizures - Types of Seizures - GeneralizedGeneralized

Generalized seizures are bilaterally symmetric; there is Generalized seizures are bilaterally symmetric; there is no local onset and although they involve the entire no local onset and although they involve the entire brain, physical control is rarely lost. brain, physical control is rarely lost.

Types of GS include:Types of GS include:i.i. Absence seizures (Absence seizures (petit mal)petit mal)-- staring, slight body staring, slight body

movement and short periods of unawareness movement and short periods of unawareness ii.ii. Myoclonic seizures-Myoclonic seizures- sudden jerks of arms and sudden jerks of arms and

legslegsiii.iii. Atonic seizures (Atonic seizures (drop attacks)-drop attacks)- suddenly suddenly

collapse or fall downcollapse or fall downiv.iv. Tonic-clonic seizures (Tonic-clonic seizures (grand mal)grand mal)-- most severe most severe

type of seizure; characterized by loss of type of seizure; characterized by loss of consciousness, body stiffening, shaking and consciousness, body stiffening, shaking and sometimes tongue bitingsometimes tongue biting 77

Partial and Generalized Partial and Generalized

Partial Seizure with Secondary Generalization

Primary Generalized Seizure

Partial Seizure

88

Etiology - Etiology - EpilepsyEpilepsy

Metabolic defects Congenital malformation Genetic predisposition Perinatal injury Postnatal trauma Myoclonic syndromes Infection Brain tumor Vascular disease Fever Drug and/or alcohol abuse

99

Pathogenesis Pathogenesis A seizure occurs when a A seizure occurs when a burst of burst of electrical impulses in the brain electrical impulses in the brain escape their normal limits (past escape their normal limits (past threshold).threshold).

They spread to neighboring areas They spread to neighboring areas and create an uncontrolled storm of and create an uncontrolled storm of cortical nerve cell electrical activity.cortical nerve cell electrical activity.

The electrical impulses can be The electrical impulses can be transmitted to the muscles, causing transmitted to the muscles, causing twitches or convulsions.twitches or convulsions.

1010

PathogenesisPathogenesis

The 19th century neurologist Hughlings Jackson The 19th century neurologist Hughlings Jackson suggested suggested ““aa sudden sudden excessiveexcessive disorderly disorderly discharge of cerebral neuronsdischarge of cerebral neurons“ as the causation “ as the causation of epileptic seizures.of epileptic seizures.

Recent studies in animal models suggest a central Recent studies in animal models suggest a central role for the excitatory neurotransmiter role for the excitatory neurotransmiter glutamateglutamate and inhibitory gamma amino butyric acid (and inhibitory gamma amino butyric acid (GABAGABA) ) (decreased)(decreased)

1111

B-Slide B-Slide 1212

Normal CNS FunctionNormal CNS Function

ExcitationInhibition

glutamate,aspartate GABA

B-Slide B-Slide 1313

Hyperexcitability reflects both Hyperexcitability reflects both increased excitation and increased excitation and decreased inhibitiondecreased inhibition

Excitation

Inhibition

GABA

glutamate,aspartate

Diagnosis Diagnosis

EEGsEEGs can be used to confirm diagnosis and determine can be used to confirm diagnosis and determine type of seizuretype of seizure

An An MRIMRI may be ordered if the initial medications pt. is on may be ordered if the initial medications pt. is on fail to control seizures or a CT scan if pt. is an older fail to control seizures or a CT scan if pt. is an older adultadult

Plasma levels of electrolytesPlasma levels of electrolytes, glucose and calcium , glucose and calcium levels, renal function tests, liver function tests and even levels, renal function tests, liver function tests and even drug screening may be performeddrug screening may be performed

Diagnostic testsDiagnostic tests include:include:

1414

Diagnosis Diagnosis

If the pt. has already been diagnosed with epilepsy: If the pt. has already been diagnosed with epilepsy: anti-epileptic drug (AED) levels may be tested to ensure anti-epileptic drug (AED) levels may be tested to ensure that the dosage levels are accuratethat the dosage levels are accurate

An ECG can exclude cardiac cause of symptoms or An ECG can exclude cardiac cause of symptoms or seizure CSF may be tested for infectionseizure CSF may be tested for infection

1515

TreatmentTreatment

Current treatment methods can control seizures for Current treatment methods can control seizures for approximately 66% of people with epilepsy.approximately 66% of people with epilepsy.

TreatmentsTreatments includeinclude::Anti-epileptic drugs are the most common form of Anti-epileptic drugs are the most common form of treatment treatment Brain surgery is performed if seizures originate in a Brain surgery is performed if seizures originate in a small, defined area in the temporal or frontal lobes, but is small, defined area in the temporal or frontal lobes, but is not common otherwise due to added risk of damaging not common otherwise due to added risk of damaging vital brain functionsvital brain functions

1616

Diagnosis & TreatmentDiagnosis & Treatment cont.cont.

Vagus nerve stimulationVagus nerve stimulation-- a vagus nerve stimulator a vagus nerve stimulator is implanted into the chest beneath the collarbone, is implanted into the chest beneath the collarbone, wraps around the vagus nerve and stimulates the wraps around the vagus nerve and stimulates the brain to inhibit seizuresbrain to inhibit seizures

Children (and some adults) who don’t respond to Children (and some adults) who don’t respond to medicinal treatment have been prescribed a high-medicinal treatment have been prescribed a high-fat, high-protein and low carbohydrate diet to fat, high-protein and low carbohydrate diet to produce ketones, which allow the body to use fat produce ketones, which allow the body to use fat instead of glucose for energy. The exact instead of glucose for energy. The exact mechanism for why this works is unknown.mechanism for why this works is unknown.

1717

Epilepsy - TreatmentEpilepsy - Treatment

The majority of pts respond to drug therapy The majority of pts respond to drug therapy (anticonvulsants). In intractable cases surgery may be (anticonvulsants). In intractable cases surgery may be necessary. The treatment target is seizure-freedom necessary. The treatment target is seizure-freedom and improvement in quality of life!and improvement in quality of life!

The commonest drugs The commonest drugs used in clinical practice are: used in clinical practice are: Carbamazepine, Sodium valproate, Lamotrigine Carbamazepine, Sodium valproate, Lamotrigine (first line drugs) (first line drugs) LevetiracetamLevetiracetam, Topiramate, Pregabaline (second line drugs) , Topiramate, Pregabaline (second line drugs) Zonisamide, Eslicarbazepine, Retigabine (new AEDs) Zonisamide, Eslicarbazepine, Retigabine (new AEDs)

Basic rules for drug treatment: Drug treatment should Basic rules for drug treatment: Drug treatment should be simple, preferably using one anticonvulsant be simple, preferably using one anticonvulsant (monotherapy). “Start low, increase slow“. (monotherapy). “Start low, increase slow“. Add-on therapy is necessary in some patients… Add-on therapy is necessary in some patients…

1818

Witness Response Witness Response

When you see someone having a seizure you should: When you see someone having a seizure you should: Loosen their clothingLoosen their clothing Move surrounded objects that the seizing individual Move surrounded objects that the seizing individual

could hurt him/herself oncould hurt him/herself on Stay until seizure ends to make sure the person is okay Stay until seizure ends to make sure the person is okay

and can get upand can get up

1919