Epilepsy cause and classification

By:Dr. Zinab Mofadl

A seizure is a symptom of many different disorders that can affect the brain, it is an event not a disease itself.

In centuries past, the word "seizure" referred to people being taken over by supernatural forces.

Seizure: is a transient occurrence of signs and/or

symptoms due to abnormal excessive or synchronous neuronal activity in the brain.Epilepsy :

is a disorder of the brain characterized by an enduring predisposition to generate epileptic seizures, and by the neurobiological, cognitive, psychological, and social consequences of this condition .

What is epilepsy:

Seizures result from an electrochemical disorder in the brain.

Each brain cell either excites or inhibits other brain cells with its discharges. When the balance of excitation and inhibition in a region of brain is moved too far in the direction of excitation, then a seizure can result.

Cause of Seizures:

Non-epilept

icepilept

ic

Febril convulsion Infection :meningitis ,encephalitis ,brain abscess Irritation: brain odemaTumer of brain Toxic :tetanus,or drugs as aminophyllineHemorrhage :trauma ,hemorrhagic blood diseaseHypoxia: hypoxic ischemic encephalopathyHypertensive, uraemic, hepatic enchephalopathyMetabolic: hypo(glycamia,calcaemia,magnesaemia) hypo or hypernatremia pyridoxine(b6) deficincy

Non-epileptic

Seizure

idiopathic secondary

•Post traumatic •Post haemorrhage•Post infection •Post toxic•Post anoxic

•Congenital Malformation •degenerative brain disorder•Tumours •inborn error of metabolism•stroke

Classification:

complex

simple

Secondary generalized

absence

Myoclonic

Tonic-clonic

Tonic Atonic

It is only involved one part of body.Partial seizures constitute 40% to 60% of the classifiable epilepsies of childhood. It is caused by focal brain lesions (tumors, infarct, dysgenesis), but most partial seizures in children are due to genetic influences (rolandic seizures).

Partial epilepsy :

Simple Partial SeizuresComplex Partial SeizuresSecondary Generalized Seizures

Types:

1-Simple Partial Seizures:consciousness is not impaired.Impaired consciousness is defined as the inability to respond normally to exogenous stimuliThe average seizure persists for 10–20 sec

With motor signs

With somatose

nsory symptoms

With autonomic symptoms

or signs

With psychic

symptoms

With motor signs

Focal motor without march

Focal motor with march (Jacksonian)Versive

Postural

Phonatory (vocalization or arrest of speech

With somatosen

sory symptoms

Somatosensory VisualAuditoryOlfactory

GustatoryVertiginous

With autonomi

c symptoms or signs epigastric

pallorsweatingpiloerectionpupillary changes

With psychic sympto

ms

Dysphasic Cognitive Dysmnesic (eg, deja-vu)Affective eg :fear

IllusionsHallucinations

2-Complex Partial Seizures:-consciousness is impaired.

-It is previously called “psychomotor seizures”, “temporal lobe seizures” or

“limbic seizures.”-Associated with aura and/or

automatism -The average seizure persists

for 1–2 min

“Aura:”Is present in approximately one third of children with SPS and CPS.

always indicates a focal onset of the seizure

Children <7 yr old are less likely than older children to report auras

Aura may presented by :

Automatisms:are a common feature of CPS in infants and children

occurring in ≈50–75% of cases

the older the child, the greater is the frequency of automatisms.

Automatisms develop after the loss of consciousness and may persist into the postictal phase.

In infants: is characterized by alimentary automatisms including :

lip smacking chewing, swallowing excessive salivation.

In older children :consists of semi-purposeful, incoordinated, and unplanned gestural automatisms, including: picking and pulling at clothing or bed sheets rubbing or caressing objects walking or running in a nondirective repetitive, and often fearful fashion.

Simple Partial Seizures

Consciousness is

INTACT

MotorSensory

Autonomicpsychic

No automatism

No aura

Complex Partial Seizures

Consciousness is

IMPAIRED

mainly motor

Automatism may occur

preceded by an aura

1. Simple partial seizures evolving to generalized seizures

2. Complex partial seizures evolving to generalized seizures

Secondary Generalized Seizures:

•benign childhood epilepsy with centrotemporal spikes (BECTS)

•Benign epilepsy with occipital spikes

•benign infantile familial convulsion syndromes

•benign infantile nonfamilial syndromes

•Nocturnal autosomal dominant frontal lobe epilepsy

Benign Epilepsy Syndromes with Partial Seizures:

•Migrating partial epilepsy

•pseudo Lennox-Gastaut syndrome.

•mesial (medial) temporal sclerosis

•Landau-Kleffner epileptic aphasia syndrome

•syndrome of continuous spike waves in slow-wave sleep

•Rasmussen's encephalitis Severe Epilepsy Syndromes with Partial Seizures:

Generlized Epilepsy:It Involves both hemispheres of the brain. Always involves loss of consciousness.

Absences

Tonic-clonicMyoclonic

Tonic

Atonic

Brief stare with unresponsiveness(<30 sec).

May have associated eye flutter or simple automatisms.

Sudden onset with arrest of activity

No aura or postictal confusion.F>M , uncommon before 5 yrs age.

Absence (petit mal):

1-Simple (typical) absence Seizure

Hyperventilation for 3-4min routinely

produces an absence seizure.Generalized 3 per second spike and wave.

80% will experience resolution with age.

20% will have convulsive seizures

Associated with myoclonic movement of the face, fingers, or extremities.

Loss of body tone.precipitated by drowsiness Produce atypical EEG spike and wave discharges at 2-2.5lsec.

2-Complex (atypical) absence seizure

It is similar to typical absences but occur at a later age and are accompanied by 4-6 Hz spike–and–slow wave and polyspike–and–slow wave discharges. These are usually associated with juvenile myoclonic epilepsy

3-Juvenile absence seizure

Common and may follow a partial seizure with a focal onset.

Associated with an aura(indicate a site of pathology).

Sudden loss of convulsion ,rolling of eyes , tonic ,then rhythmic clonic convulsion .

Associated with sphincter incontinences.Posticteal sleep may continues for 30 min to several hrs

Generalized tonic clonic seizure

Aura Convulsion Postictal

Sudden single jerks of group of muscle.

Single or in clustersNo alteration in consciousnessAssociated with loss of body tone and falling or slumping forward.

May progress to clonic-tonic seizure

Generalized multispike wave.Five distinct subgroupings can be identified.

Myoclonic

are epileptic drop attacksNo warning, abrupt onset. Injuries common.Very difficult to treat.May respond well to VNSCorpus callosotomy may prevent falls.

Atonic

•Benign myoclonic epilepsy of infancy

•Febrile seizures plus syndrome

•Juvenile myoclonic epilepsy (Janz syndrome)

•photoparoxysmal epilepsy

Benign Generalized Epilepsies:

•Early myoclonic infantile encephalopathy (EMIE)

•Early epileptic infantile encephalopathy (EEIE, Ohtahara syndrome

•West syndrome

•Lennox-Gastaut syndromeSevere Generalized Epilepsies:

•Myoclonic astatic epilepsy

•Progressive myoclonic epilepsies

•Myoclonic encephalopathy in nonprogressive disorders

•Landau-Kleffner syndrome

Begins during infancy . Myoclonic movements confined to the neck, trunk, and

extremities. EEG is normal. Prognosis is good . Normal development and the cessation of myoclonus

by 2yr of age. An anticonvulsant is not indicated.

Benign Myoclonus of Infancy:

Begins at 12-16 yrs of age. ~5% of epilepsy. Autosomal dominant inheritance. At beginning early morning myoclonic jerks occur

then abate later in morning. A few yrs later gen. tonic-clonic seizure with

myoclonus.

Juvenile Myoclonic Epilepsy (JME) (Janz syndrome)

EEG show 4-6 /sec irreguler spikes. Neurological exam. normal. Dramatically response to valporate which required

lifelong.

The mean age of onset is ~2yr (6mo to 4yr).Near normal before the onset of seizure.May occur several times daily, or children may be

seizure-free for weeks .Approximately half of patients occasionally have tonic-

clonic seizures. The EEG shows fast spike wave complexes of >2.5H2

and a normal background rhythm in most cases.

.2Typical Myoclonic Epilepsy of Early Childhood

One third of the children have a positive family history of epilepsy(a genetic etiology)

The long-term outcome is relatively favorable.Mental retardation develops in the minority.>50%are seizure-free several years laterLearning and language problems and emotional and

behavioral disorders.

A heterogeneous group of disorders with a uniformly poor prognosis.

Focal or generalized tonic-clonic seizures beginning in the 1st yr of life.

Frequently develops into status epilepticus.One third have evidence of delayed developmental

milestones.

.3Complex Myoclonic Epilepsies

A history of hypoxic-ischemic encephalopathy in the perinatal period.

A family history of epilepsy is much less prominent. Lennox-Gastaut syndrome:(triad of intractable

seizures of various types, a slow spike wave EEG during the awake state, and mental retardation).

Slow spike waves and are refractory to anticonvulsants.

Frequency of mental retardation and behavioral problems is ~75% of all patients.

Treatment with valproic acid or benzodiazepines may decrease

The ketogenic diet should be considered for patients have refractory seizures .

Heterogeneous group of rare genetic disorders uniformly has a grave prognosis.

These include : Lafora disease, myoclonic epilepsy with ragged-red fibers( MERRF) Sialidosis type

1,ceroid lipofuscinosis ,Juvenile neuropathic, Gaucher disease and luvenile neuroaxonal dystrophy.

.5Progressive Myoclonic Epilepsies

Generalized tonic-clonic seizures ass. with myoclonic jerks with progression of disease.

Mental deterioration within the 1yr of disease. Cerebraller & extra pyramidal signs are prominent. EEG shows polyspike –wave discharge in occipital on

disorganized back ground.Myoclonic jerk are difficult to control

Lafora disease is an ARD presents in children between 10 and 18 yr.

Diagnosed by a skin biopsy characteristic periodic acid-Schiff positive inclusion, prominent in the sweat

gland.

Flexion or extension spasmsTend to occur in clustersCryptogenic vs. symptomatic

Many potential causesOnset: Birth to 2 years

Peak onset: 4-8 months80% develop mental retardation60-70% have lifelong epilepsyHypsarrhythmia pattern on EEG

Infantile Spasms