epilepsy
DESCRIPTION
medicineTRANSCRIPT
DEFINITION• Came from the Greek word epilepsia which
means to seize• Is a chronic neurologic disorder characterised
by seizures• The seizures are transient signs or symptoms
of abnormal, excessive but synchronous neuronal activity in the brain
• Should not be understood as a single disorder but rather as a syndrome with vastly divergent symptoms with all involving episodic abnormal electrical activity in the brain
EPIDEMIOLOGY• About 50 million people world wide have
epilepsy• About 20,000,000 cases in US• About 3,000,000 in UK• It is placed at 14-57 per thousand population
for Africa and some South American countries• Generally it has been placed at 40-70per
100,000 population for developed countries and 100-190 per 100,000 population for developing countries.
CLASSIFICATION• Epilepsies are classified in five ways• By their first cause or aetiology• By the observable manifestations of the
seizures known as semiology• By the location in the brain where the
seizures originate• As a part of discrete identifiable medical
syndromes• By the event that triggers the seizure as in
primary reading epilepsy.
CLASSIFICATIONIn 1981. the International League against
epilepsy (ILAE) proposed a classification scheme for individual seizures that is still in common use.
It is simple
ClassificationGeneralised means the source is distributed
around the brain and it involves loss of consciousnessTonic – clonicTonicClonicAbsenceAtonic
ClassificationPartial or focal when the source of the
seizure within the brain is localisedSimple: consciousness is unaffectedComplex: involving loss of consciousnessSimple with secondary generalisationComplex with secondary generalisationSimple becoming complex with secondary
generalisation
ClassificationUnclassified these are seizure types that
could not fit into any particular category
ClassificationSince 1997 the ILAE has been working on a
new scheme that have five axisIctal phenomenon ( pertaining to an epileptic
seizure )Seizure typeAetiologySyndromeImpairment
SIMPLE PARTIAL SEIZURES• Can present with the following signs
– Motor signs• Focal without a match• Focal with a match (Jacksonian )• Postural• Phonatory ( vocalisation, or arrest of speech )
– With somatosensory or special sensory symptoms e.g simple hallucinations like tingling, light flashes, buzzing.• Somatosensory• Visual
SIMPLE PARTIAL SEIZURES• Auditoy• Olfactory• Gastatory• Vertiginous
– With autonomic symptoms or signs• Epigastric sensation• Pallor• Sweating• Flushing• Piloerection• Pupillary dilatation
SIMPLE PARTIAL SEIZURESWith psychic symptoms ( disturbance of higher
centre functions ). These symptoms however, rarely occurs without impairment of consciousness and are therefore more commonly experienced as complex partial seizures Dysphasic Cognitive ( dreamy state, distortion of time ) Dysmesic e.g dejavu Affective ( fear, anger etc )
CAUSES • The word epilepsy actually denotes idiopathic
nature of the problem • The diagnosis requires that the seizures
occurs spontaneously• Nevertheless, certain epileptic syndromes
require particular precipitants or triggers; these are termed reflex epilepsy– Patients with primary reading epilepsy have
their seizures triggered by reading– Photosensitive epilepsy is limited to seizures
triggered by flashing lights.
CAUSES – Children with childhood absence seizures may
be susceptible to hyperventilation
• Other precipitants can facilitate rather than obligately trigger seizures in susceptible individuals
• Emotional stress • Sleep deprivation• Sleep itself• Heat stress• Alcohol• Fever as in febrile convulsions
CAUSES • The influence of various precipitants varies
with the epileptic syndrome• In different age groups some causes are
common– Neonatal age• HIE ( Hypoxic ischaemic encephalopathy )• CNS infections• Trauma• Congenital abnormalities• Metabolic disorders
CAUSES – Infancy and early childhood• Febrile convulsion
– Childhood• Well defined epilepsy syndromes
– Adolescents and adulthood• CNS lesions• Stress • Trauma• CNS infections• Brain tumours• Illicit drug use
PATHOPHYSIOLOGY• Seizures are paroxysmal manifestation of
electrical properties of the cerebral cortex• A seizure results when a sudden imbalance
occurs between the excitatory and inhibitory forces within the network of cortical neurons in favour of a sudden onset net excitation.
• Depending on the affected cortical network the manifestation will differ if it is the visual cortex, the clinical manifestation are visual. Other areas may give rise to sensory, gastatory or motor manifestations.
INVESTIGATIONS• FBC• MPS• LP• Blood culture• EEG may tell seizure type• Neuroimaging; these may provide evidence
about structural abnormalities that could be the cause for the seizures– CT scan– MRI
TREATMENTIndications for starting treatment include
A patient with more than one seizure episodeThe older indication was 2 episodes in 6
months or 3 episodes in a yearThis is taken in conjunction with abnormal
results like abnormal EEG, MRI or CT scanIndications also reflect seizure type as complex
seizures require treatment
DRUGSBlockers of repetitive activation of sodium
channelsPhenytoinCarbamazepineOxcarbamazepineLamotrigineTopiramate
Enhancer of slow activation of sodium channels
DRUGSLacosamideRufinamide
GABA – A receptor enhancersPhenobarbitalBenzodiazepines
Glutamate modulatorsTopiramateLamotrigineFelbamate
DRUGST. Calcium Channel blockers
EthusuximideValproate
N- and L- Calcium channel blockersLamotrigineTopiramateZonisamideValproate
DRUGSH. Current modulators
GabapntinLamotrigine
Blockers of unique binding sitesGabapentinLenetiracetin
Carbonic anhydrase inhibitorsTopiramateZonisamide
Indication for discontinuing treatmentSeizure free for 2 – 5 yearsOver 30% of patients with epilepsy do not
have seizure control even with the best medications
Other treatment modalitiesSurgery
Palliative: Anterior callostomy which is rarely done now. Used for intractable atonic seizures
Curative Lobectomy Lesionectomy
DietKetogenic diet has been effective in improving
seizure control in selected patients
Other treatment modalitiesElectrical stimulation; one approved method
is the vagus nerve stimulation ( VNS )Stem cell transplantation
PROGNOSISThe patient prognosis for disability and for
recurrence of epileptic seizures depends on the type of seizure and the epileptic syndrome in question.
Prognosis is worse with partial seizuresPrognosis is worse with frequent seizures
before presentation
FEBRILE CONVULSIONSDefinition: Convulsion with fever in children
aged 6 months to 5 years whose cause is of an extra cranial origin. Usually lasts 15minutes or less.
About 4% of people will have one seizure episode in their life time
CLASSIFICATIONSimpleComplex
CAUSESAny condition that causes a rapid increase in
temperatureAOMMalariaMeaslesBronchopneumoniaPost immunisation
DIFFERENTIAL DIAGNOSISMeningitisEncephalitisCerebral malariaMetabolic problems
HypoglycemiaHypocalcaemia
INVVESTIGATIONSFBCMPBlood cultureViral serologyLPRBS Serum calcium
TREATMENTControl seizureTreat cause Long term seizure control
STATUS EPILEPTICUSA life threatening condition in which the
brain is in a state of persistent seizuresDefined as one continuous seizure lasting
more than 30minutes or recurring seizures lasting more than 30 minutes without regaining consciousness in between.
Mortality is in the upward of 20% if not treated early
STATUS EPILEPTICUSWith optimal neurologic care a good
prognosis is expected
TREATMENTMake sure patient is breathingClear airway by suctioning if need beDrugs
Diazepam given intravenously its effect lasts 5 – 15 minutes may need to be repeated ( though its half life is 30 hours )
Lorazepam when available lasts longer.
TREATMENTPhenytoin or fosphenytoin: takes 15 – 30
minutes to act so could be administered together with diazepam
Sodium valproate may also be used intravenously
Phenobarbitone or barbiturates
TREATMENTPractice here
DiazepamPhenobarbitoneLargactil
When all failAnaesthesia with patient paralysis and
ventilation