Epileptic Neurological Disorders

8/3/2019 Epileptic Neurological Disorders

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Seizures and Epilepsy

Carl E. Stafstrom, MD, PhD

Chief, Pediatric Neurology

University of Wisconsin-Madison



OUTLINE

1. Definitions

2. Classification

3. How to diagnose? 4. Pathophysiology

5. Case examples

April 20, 2009



Definitions

Seizure (or epileptic seizure)

± Abnormal firing of neurons causing neurologicdysfunction:

awareness

motor control

sensory perception

autonomic function



Definitions


- Specific clinical manifestations of a seizuredepend upon which parts of the brain affected

± Humunculus: L -> Arm -> HandQuickTime and a

decompressor

are needed to see this picture.



Definitions


- A seizure is a single event

- Tempo: usually sudden onset, seconds-

minutes

- Status epilepticus (longer seizures)necessitates intervention



Definitions

Epilepsy (or epilepsy syndrome)

± Recurrent seizures



Definitions


± Duration of epilepsy is variable ± from

complete resolution to lifetime disorder



Definitions


More than just seizures!

Cognitive, behavioral, mood

changes

Stigma, social factors

Quality of life

Drug side effects



Seizure Classification

clinical observationsEEG findings

Focal (partial)

± Begin in one part of

the brain

Generalized

± Begin in both

hemispheres at once

A seizure begins either focally or generalized, and it

matters ± for pathophysiology, treatment, prognosis





Focal seizures

Simple focal

seizureComplex focal seizure

Secondarily generalized

seizure

Consciousnesspreserved

³aura´

Consciousness impairedautomatisms

Consciousness impaired

+

bilateral cerebral

involvementSimple: consciousness preserved or complex (consciousness impaired)

Both can generalize to other hemisphere and rest of brain



Generalized seizures - types

Generalized tonic-clonic (grand mal)

Clonic (jerking)

Tonic (tightening of muscles) Atonic (total loss of tone)

Myoclonic (fast jerks)

Absence (petit mal)



How do we diagnose epilepsy?

History

± Signs/symptoms

± Localization (cortex; which lobe?)

± Tempo (acute onset; duration seconds-minutes)

± Patient specific factors

Age

Etiology (genetic vs acquired)

Concurrent medical conditions epilepsy syndrome

Family history

Medication responsiveness

Lab (EEG findings)




Electroencephalography (EEG) ± a

³map´ of the brain¶s electrical activity

Signal through dura, CSF,

skin, bone, hair = inexact




Neuroimaging (MRI, CT, PET)

Cortical

dysplasia abnormal neural

circuits

epileptic focus

L frontal lobe look like

one single mass

Child w/ cortical

dysplasia




Other tests

± Metabolic testing

± Genetic testing

± Neuropsychology




± Rule out seizure ³mimics´

± These disorders share some features of epileptic seizures

such as tempo, signs, symptoms, etc.:

Syncope

Movement disorders: Tics, tremor, choreoathetosis

Hyperventilation/anxiety

Migraine

Episodic dyscontrol (rage)

Daydreaming (absence seizure? Complex-partial?) Pseudoseizures (Somatization disorder)



Why does a seizure occur?

Imbalance of excitation and inhibition

E I

What factors alter this balance?



Why does a seizure occur?

E

IDecreased K

channel activity

Decreased

inhibitory synapse

function (GABA)

Increased Na

channel activity

Increasedexcitatory

synapse function

(glutamate,

network

connectivity)Intracellular recordings of

normal and epileptic

neurons

?

and/or



Case examples

1. Focal epilepsy ± temporal lobe epilepsy

2. Generalized epilepsy ± absence epilepsy

These cases illustrate t he etiology, pat hophysiology, and clinical approac h to a

few common and representative types of

epilepsy



Case 1: Focal sz secondary generalization

A 16 y.o. girl presents with multiple seizures per

week, beginning 3 years ago

Seizures consist of brief stare head turn to left

side fumble with hand tonic-clonicconvulsion of all limbs for ~ 2 min, followed by

sleep

Hx:

± Normal pregnancy and birth

± Prolonged (40 min) febrile sz at 2 y.o. (most febrile

seizures are benign, some predispose)

± Moderate developmental delay, special ed



Video 1 will be here

R. Hippo - stare

R. Motor cortex: head turn, arm jerk

L. Motor cortex after crossing corpus collosum: arm jerk

Generalized: all limbs affected



Case 1: Temporal lobe epilepsy

Neuronal injury early in life (here, a prolonged

febrile sz), followed by several year ³latent

period´ during which brain becomes epileptic

Sz manifestations vary from aura to complexfocal sz to GTC convulsion

Aura -

± Self-described perception of abnormal feeling, odor, taste, etc.

± Represents a simple partial seizure



Case 1: Temporal lobe epilepsy

TLE tends to become refractory to medications;

may respond to surgical resection of

hippocampus

Pathological basis is scarring (sclerosis) of

hippocampus



sclerotic (scarred)

hippocampusnormal hippocampus

HIPPO! ->



N ormal

HS

dg

C A3 C A3

dg

dg dg C A3 C A3

Hippocampal (medial temporal) sclerosis

Neuron death and

gliosis/scarring

(dentate gyrus)



Case 2: Generalized seizure (absence type)

Healthy, normally developing 11 y.o. girl

Episodes of staring and ³spaciness´ in class, up

to 20 per day, 10 sec each

Parents also noticed staring spells at home,

described as ³like hitting the pause button on the

VCR´

Seizures readily controlled with medication In clinic, episodes elicited by hyperventilation



Video 2 will be here

Little girl blowing on pin-wheel to induce seizure - a couple blinks w/ stopped

blowing, didn¶t hear pink spaghetti and red something or another.



Case 2: Absence epilepsy

Staring/unresponsive spells in otherwise

normal children

EEG shows ³3 Hz spike wave´ during

seizure; abrupt onset and offset

Pathophysiology is thalamo-cortical loop:

abnormal calcium channels

Genetic basis, no pathology

Responds well to medication; children

often outgrow

Meds: valproic acid and other.



Absence seizure: 3 Hz generalized spike-wave

1 2 3

Normal then 3 Hz. Spike-wave



THERAPEUTIC APPROACHES

1. Avoid triggers ± sleep deprivation,

alcohol, flashing lights

± Blowing on pinwheel induces hypocapnea

and decreased blood flow to brain

2. Pharmacological (upcoming lecture)

3. Surgery (selected cases)

4. Other

Dietary (e.g., ketogenic diet)

Brain stimulation (e.g., vagus nerve

stimulator)



Summary

Seizures come in 2 basic flavors: focal and

generalized

Epilepsy consists of recurrent seizures

Epilepsy is a disorder of neuronal excitability:

excitation > inhibition

Diverse clinical manifestations, ranging from

staring to convulsion Management of a patient with epilepsy involves

treating both the seizures and the associated

cognitive, emotional, and social concerns

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Epileptic Neurological Disorders

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