Transcript Seizure Dx and Mgt II

Seizures
Diagnosis and
Management
Nisha Kanani, David Cherney
2004
Resources
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Primary Care: Epilepsy. Browne T. R., Holmes G.
L. NEJM; 344:1145-1151, Apr 12, 2001.
Current Concepts: Patients with refractory seizures.
Devinsky O. NEJM; 340: 1565-1570, May 20, 1999
Consensus statements: Medical management of
epilepsy. Neurology; 51(5 suppl4): S39-43, Nov 01
1998
Textbook of clinical neurology. Greenberg
Canadian Driving Guidelines Online
Objectives
1. First seizure evaluation in adults
2. Seizure classification
3. Management options
Case
• 32 y/o male taxi-driver is referred
for evaluation of a “spell” while
walking to the corner store, after
which he was found on the ground.
• Brought in by EMS to the ER
• Subsequently sent home
• What are you going to do and tell
the patient?
Definitions
• Seizure: transient disturbance in
cerebral function caused by
abnormal neuronal discharge
• Epilepsy: group of disorders
represented by recurrent seizures
(3% lifetime prevalence)
Evaluating seizures:
1) Is this a seizure?
2) What type of seizure is this? (implications
on treatment)
3) Is there an underlying cause?
Is this a Seizure? Seizure Mimics:
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Classic migraines
include transient neurologic symptoms (as in partial seizures).
epilepsy patients twice as likely to have migraines.
2)
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Syncope
Postural, flaccid paralysis, pre-syncope symptoms, no post-ictal
state
May have fasiculations (convulsive syncope)
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TIA
Usually no LOC unless basilar stroke, usually negative findings not
positive. Sometimes confusing if post-ictal Todd’s paralysis
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Pseudo-seizures
10-45% of patients with refractory epilepsy. Look for history of
abuse. Patients can have both.
Movement disorders
5)
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Is there an underlying cause?
(rule out secondary causes of seizures)
1o neurologic disorder
Systemic disorder
•Head trauma
•Cancer
•Hemorrage
•Stroke
•Vascular malformations
•Meningitis/encephalitis
•Hypoglycemia
•Hyponatremia
•Hypocalcemia
•Uremia
•Hepatic encephalopathy
•Drug OD/withdrawal
•Hyperosmolar states
•Hyperthermia
History
• Witness testimony is key!
• Triggers, ictal behaviors, LOC,
behaviour during seizure and the
postictal state.
• Seizure precipitants or triggers:
– strong emotions, intense exercise, flashing
lights, and loud music (often immediately
before the seizure)
– fever, menstruation, lack of sleep, and
stress
History
Ask about . . .
Drugs, alcohol, constitutional symptoms,
HIV risk factors, fever, head trauma.
Family History (absence and myoclonic
seizures may be inherited)
Physical examination
• Generally unrevealing
• Look for signs of disorders associated with
seizures.
• Head trauma, meningismus, sinus infection.
• Focal or diffuse neurological abnormalities.
• Mental status abnormalities suggest lesions in
the anterior frontal, parietal, or temporal
lobes.
• Evaluate for lateralizing abnormalities:
weakness, hyperreflexia, positive Babinski sign
Laboratory evaluation
• Glucose, calcium, magnesium,
hematology studies, renal function
tests, lytes toxicology screens.
• Acute postictal changes: metabolic
acidosis and leukocytosis, high CK
• LP if risk factors for infection
(fever, HIV positive).
Electroencephalography
• Information provided:
• Presence of abnormal electrical activity
• Information of type of seizure disorder
• Location of seizure focus
• Perform study >48hrs after seizure
• Include recordings during sleep, photic
stimulation, hyperventilation.
• 50% of patients with epilepsy have
normal single EEG
Electroencephalography
• If normal and high suspicion, repeat
study after sleep deprivation
• 10% of persons with true seizure with
have normal multiple EEG studies
• +EEG  likelihood of second seizure
over two years
Neuroimaging in adults
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with 1 seizure
• Retrospective review of 148 patients
studied within 30 days of the seizure
• Structural lesion was identified by CT in
55 (37 percent); 16 (11 percent) had
metabolic seizures
• CT findings agreed with the results of
neurological examination in 82 percent
of cases.
Ramirez-Lassepas, et al. Value of computed tomographic scan in the evaluation of
adult patients after their first seizure. Ann Neurol 1984; 15:536.
Neuroimaging
• All patients should receive
neuroimaging.
• MRI preferred over CT to identify
small lesions such as cortical
dysplasias, infarcts, or tumors.
• CT scan is suitable in emergency
situations to exclude a mass lesion,
hemorrhage, or large stroke.
When to initiate Antiepileptic drug
therapy
1) Two or more seizures
2) Single seizure secondary to identified CNS
lesion with an epileptogenic focus
3) Consider if significant occupational risk if
patient suffers a second event.
4) Consider if single seizure event with one or
more risk factors for recurrent seizures
5) Consider in the elderly patient with increased
risk of seizure related morbidity (age,
prolonged post-ictal state)
Risk of seizure recurrence in a
patient with an apparently
unprovoked or idiopathic seizure
• 31 to 71% risk in the first 12 months after the
initial seizure.
• Risk factors associated with recurrent seizures
include the following:
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(1)
(2)
(3)
(4)
(5)
evidence of a structural lesion
EEG abnormalities
partial type seizure
family history of seizures
focal abnormalities on exam
• Most patients with one or more of these risk
factors should be treated
Antiepileptic Drugs of Choice
Primary Generalized
Tonic-Clonic
Partial
Absence
Atypical Absence,
Myoclonic, Atonic
First-Line
Valproic acid
Carbamezepine
Phenytoin
Carbamazepine
Phenytoin
Ethosuximide
Valproate
Valproic acid
Alternatives
Lamotrigine
Primidone
Phenobarbital
Gabapentin
Topiramate
Tiagabine
Primidone
Phenobarbital
Lamotrigine
Clonazepam
Lamotrigine
Topiramate
Clonazepam
Felbamate
Principles of Treatment
• Start with an average dose of a first line drug
• Poor control? Address compliance, maximize drug
dose, confirm right diagnosis (partial complex v.s
generalized)
• Majority of patients are controlled with single
antiepileptic drug.
• This drug can be gradually withdrawn if seizure free
for two years.
• Seizures recur in 25% of patients without risk factors
and 50% of patients without risk factors.
• The drug can be reduced by 25% every two to four
weeks.
Principles of Treatment
• 20-35% of patients with epilepsy have persistent
seizures despite medical therapy.
• If poor control with maximal dose, monotherapy with
second drug.
• Continue to administer first drug until a full dose of
second drug reached, then gradually withdraw first
drug.
• If monotherapy with two drugs fail, patient may need
re-evaluation (repeat MRI/EEG) before polytherapy
commenced (1998 guidelines).
Side effects
• Idiosyncratic toxicity:
– rash, bone marrow suppression, or
hepatotoxicity.
• Require laboratory tests (e.g.,
complete blood count and liver
function tests)
– baseline
– during initial dosing and titration
Other management issues:
• Impact on independence, self-esteem,
employment.
Driving regulations:
• Private drivers cannot drive for 3 months
after a single seizure.
• Private drivers can resume driving after being
seizure free for 12 months on medication.
Canadian
Guidelines
Side effects
Neurologic Consultation (NEJM 2001)
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Change in the type of seizure
Uncertain diagnosis (e.g. normal EEG)
Lack of seizure control in 3 months
Failure of two monotherapies
Patient is considering pregnancy
Prolonged post-ictal state
History of status epilepticus
Summary
• Management after 1st seizure
involves lots of discussion with
patient about risks/benefits
• Remember impact on driving: tell
the ministry!
• When in doubt about management
(especially medications), get a
neurologist involved