Epileptic Neurological Disorders
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Transcript of 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
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OUTLINE
1. Definitions
2. Classification
3. How to diagnose? 4. Pathophysiology
5. Case examples
April 20, 2009
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Definitions
Seizure (or epileptic seizure)
± Abnormal firing of neurons causing neurologicdysfunction:
awareness
motor control
sensory perception
autonomic function
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Definitions
Seizure (or epileptic seizure)
- 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.
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Definitions
Seizure (or epileptic seizure)
- A seizure is a single event
- Tempo: usually sudden onset, seconds-
minutes
- Status epilepticus (longer seizures)necessitates intervention
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Definitions
Epilepsy (or epilepsy syndrome)
± Recurrent seizures
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Definitions
Epilepsy (or epilepsy syndrome)
± Duration of epilepsy is variable ± from
complete resolution to lifetime disorder
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Definitions
Epilepsy (or epilepsy syndrome)
More than just seizures!
Cognitive, behavioral, mood
changes
Stigma, social factors
Quality of life
Drug side effects
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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
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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
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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)
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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)
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How do we diagnose epilepsy?
Electroencephalography (EEG) ± a
³map´ of the brain¶s electrical activity
Signal through dura, CSF,
skin, bone, hair = inexact
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How do we diagnose epilepsy?
Neuroimaging (MRI, CT, PET)
Cortical
dysplasia abnormal neural
circuits
epileptic focus
L frontal lobe look like
one single mass
Child w/ cortical
dysplasia
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How do we diagnose epilepsy?
Other tests
± Metabolic testing
± Genetic testing
± Neuropsychology
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How do we diagnose epilepsy?
± 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)
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Why does a seizure occur?
Imbalance of excitation and inhibition
E I
What factors alter this balance?
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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
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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
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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
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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
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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
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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
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sclerotic (scarred)
hippocampusnormal hippocampus
HIPPO! ->
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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)
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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
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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.
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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.
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Absence seizure: 3 Hz generalized spike-wave
1 2 3
Normal then 3 Hz. Spike-wave
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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)
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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