Transcript A Practical Approach to The Diagnosis and Evaluation of

A Practical Approach to
The Diagnosis and
Evaluation of Seizures
Carol Leicher MD
Connecticut Children’s Medical Center
University of Connecticut School of Medicine
Three basic questions
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1. Is it a seizure?
– If so, what kind?
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2. What caused it?
3. What should be done?
Seizure
A seizure is a set of clinical symptoms
associated with abnormal electrical activity
in neurons in the cortex of the brain.
The clinical characteristics of a seizure are the
result of the area of the brain that is
abnormally stimulated.
Epilepsy is a clinical condition in which there
are multiple seizures that are unprovoked.
Types of seizures
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Generalized seizures
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Focal (or partial seizures)
Generalized seizures
– Generalized seizures arise from both sides
of the brain simultaneously. Motor activity
is symmetrical and alteration of
consciousness occurs.
– Ex. Primary generalized seizures (grand mal)
Absence seizures (petit mal)
 Myoclonic seizures, atonic seizures
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Focal (Partial seizures)
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Arise from one area of the cortex and may
spread to involve adjacent areas or distant
areas
Examples:
– Simple partial seizures
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Symptoms are referable to the area of the brain
involved, no alteration of consciousness
– Complex partial seizures
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Partial seizures with alteration of consciousness
– Partial seizures with secondary generalization
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Partial seizure at onset (aura) followed by generalized
convulsive activity
Seizure like episodes
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Syncope
– Syncopal seizures may have tonic stiffening,
clonic jerking and/or post-ictal confusion
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Parasomnias
– Sleepwalking, night terrors
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Hyperventilation
Stereotypies/Tics
Staring spells
Diagnosis is largely based
on the history of the event*
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Precipitating factors
– Position, activity, intercurrent illness, medications
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Description of the episode
– Eye movements, body movements, one sided or both
sides, loss of consciousness or alteration of
consciousness, incontinence, duration, aftereffects
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Predisposing factors
– Past medical history, recent illness or neurological
symptoms, family history
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*Is it a seizure, if so what kind?
Etiology of Seizure
– Symptomatic seizures
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Acute/subacute
– Metabolic causes
 Hypoglycemia, hypo or hypernatremia, hypocalemia
 Intoxications/ toxins (lead)
– Infectious/Inflammatory
 Meningitis, encephalitis, sepsis
 Post-infectious or autoimmune causes
– Fever*
– Trauma
– Vascular accidents
Symptomatic seizures,
part 2
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Chronic/ Progressive
– Remote insults
 Perinatal asphyxia or vascular insult
 Past head injury
– Developmental brain abnormalities
 Agenesis of the corpus callosum,
schizencephaly, cortical dysplasia
– Inborn errors of metabolism
 Storage disorders, amino acid disorders,
organic acid disorders
– Neurocutaneous disorders
– Cerebral degenerative diseases
Idiopathic seizures
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The cause of the seizure can not be
determined by conventional testing or
Seizures of genetic origin in which
seizures are the only manifestation.
This category may comprise as much
as 60% of all childhood seizure
disorders.
Determining the cause of
a child’s seizure(s) *
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History
– Associated symptoms, intercurrent illness, recent
medications, exposures (drugs,toxins, pets), past medical
history ( birth history, developmental history, family
history)
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Examination
– Fever or other abnormal vital signs
– Head size, skin abnormalities (hypo/hyperpigmented
areas) ,menigismus, asymmetry of the face or the
extremities, enlarged organs, dysmorphic features
– Alteration of mental status, cranial nerve abnormalities,
motor tone or strength or reflex changes, gait
abnormalities,ataxia, sensory abnormalities.
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*What caused it?
Diagnostic Studies
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Bloodwork - electrolytes, Ca, glucose
Urine- toxicology, amino acid and organic acid
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EEG
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measurement*
– Useful for evaluating interictal abnormalities
– Occasionally useful for determining nature of a
clinical symptom (absence seizures, tics or other
frequent movements)
– Helpful in predicting recurrence of seizures.
– A normal EEG does not exclude a diagnosis of
seizure.
Diagnostic studies #2
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Ambulatory EEG
– Allows for Ictal recording- ie, EEG activity during
a suspected episode
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Drawbacks- technical, availability, depends on
patient/parent to indicate when the episodes are
occurring
Videotelemetry
– Simultaneous recording of EEG and video of
patient.
– Can be done as a day procedure or as inpatient
– Episodes must occur with some frequency
Diagnostic Studies#3
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Imaging procedures
– CTT is not the procedure of choice but is
appropriate in emergencies, especially trauma
– MRI is the imaging procedure of choice
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Abnormal neurological examination
Focal seizure activity
Focal findings on EEG
– PET scanning is a specialized procedure done in
limited circumstances (usually as part of
evaluation of intractable seizures or when a
surgical treatment is proposed.
Treatment Decisions*
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The decision to treat depends on
evaluation of risks and benefits
– Risk of subsequent seizures
– Risk of treatment
– Particular circumstances of patient
– *What to do about it?
Risks of further seizures
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Risk of a second seizure is 20-30% if:
– Examination, EEG and CTT (imaging study) is
normal (and careful review of history discloses
no other events)
– Exceptions: Absence seizures. Myoclonic seizures
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Risk of a second seizure if EEG is abnormal
is 60%
Risk of a third seizure is 70%
Risk of having another
seizure
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Most seizures do not produce injury to
the brain.
Seizures in a bad place- bath, driving a car,
climbing, riding a bicycle etc.
Prolonged seizure which can lead to hypoxia
or secondary complications.
Sudden unexplained death- a very rare
complication of seizures, particularly in
children.
Risk of treatment
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Medication side effects
– Severe- liver failure, aplastic anemia,
severe allergic reaction (Stevens-Johnson
syndrome)
– Decreased alertness, personality/behavior
changes, weight loss/gain
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Social stigma
Treatment
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Discuss risks and benefits with patient and
parent based on available statistics
If 1st seizure with lower risk of recurrence,
consider no treatment.
Use of rectal valium as a “rescue measure”
If decision to treat, choose a medication
based on seizure type, age of patient and
side effect profile.
Monotherapy is generally preferable,
especially in first line treatment.
Anticonvulsant
medications
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Generalized seizures
Divalproex sodium
Zonisamide
Topiramate
Lamotrigine
Levetiracetam
Rufinamide
Ethosuximide*
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Partial Seizures
– Carbamazepine
– Oxycarbazepine
– Zonisamide
– Topiramate
– Levetiracetam
– Lamotrigine
– Phenytoin
– Phenobarbital*
Other Treatment Alternatives
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Dietary treatment
– Ketogenic diet
– Modified Atkins diet
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Surgical treatment
– Vagal nerve stimulator
– Surgical removal of seizure focus
Algorithm
Initial Event
History- eyewitness report if possible
Probable seizure
Other
Another lecture
Physical Examination
Normal
EEG, imaging study if
EEG focal
If isolated event, no
treatment or Rectal
valium
Abnormal
EEG,Imaging study, consider
more emergent evaluation
If multiple episodes
discuss medication
Historical Clues
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Precipitating factors
– Seizures may be precipitated by flashing lights,
hyperventilation, illness or being overtired (stress?)
– Syncope is precipitated by standing up, being
overheated, sight of blood, frightening event
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State of alertness- syncope doesn’t occur in sleep,
Seizures may occur in sleep or wakefulness.
Parasomnias only occur in sleep.
Further historical cues
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Position- seizures may occur in any position,
syncope usually occurs when sitting or standing
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Eye movements- eyes are usually closed or
partially open during a syncopal episode, more
likely to be open during a seizure. The presence of
deviation of the eyes to one side or another
suggests a partial seizure.
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Seizures that affect one side of the body more
than the other are likely to be focal in origin.
Syncopal episodes are usually symmetrical.
Staring vs. Absence vs.
Partial Complex seizures
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Staring spells are more apt to occur when the
patient is passive, listening to a teacher, or parent
or watching TV. They can be of indeterminate
length and are interruptible by voice or touch.
Absence seizures can occur in the midst of activity,
usually brief 10-20 seconds. There may be eye
blinking/fluttering or subtle head movements. The
patient recovers very quickly. Incontinence may
occur.
Partial complex seizures are usually 1-2 minutes in
length, and can not be interrupted. There are often
stereotypic movements and postictal confusion is
common.
Generalized seizures vs
Partial Seizures
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Generalized seizures have sudden onset
without warning. Motor symptoms are
symmetrical. Postictal state is common
when there is convulsive activity but not for
absence or myoclonic seizures
Partial seizures may begin with localized
symptoms that the patient is aware of
(aura) and may have asymmetric motor
symptoms. Postictal state is common, even
without convulsive activity.
Algorithm
Initial Event
History- eyewitness report if possible
Probable seizure
Other
Another lecture
Physical Examination
Normal
EEG, imaging study if
EEG focal
If isolated event, no
treatment or Rectal
valium
Abnormal
EEG,Imaging study, consider
more emergent evaluation
If multiple episodes
discuss medication