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Seizure Diagnosis and Management

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					  Seizures
  Diagnosis and
  Management

Nisha Kanani, David Cherney
           2004
                 Resources
•   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:
1)    Classic migraines
•     include transient neurologic symptoms (as in partial seizures).
•     epilepsy patients twice as likely to have migraines.

2)    Syncope
•     Postural, flaccid paralysis, pre-syncope symptoms, no post-ictal
      state
•     May have fasiculations (convulsive syncope)

3)    TIA
•     Usually no LOC unless basilar stroke, usually negative findings not
      positive. Sometimes confusing if post-ictal Todd’s paralysis

4)    Pseudo-seizures
•     10-45% of patients with refractory epilepsy. Look for history of
      abuse. Patients can have both.
5)    Movement disorders
•
       Is there an underlying cause?

   (rule out secondary causes of seizures)
1o neurologic disorder     Systemic disorder
•Head trauma               •Hypoglycemia
•Cancer                    •Hyponatremia
•Hemorrage                 •Hypocalcemia
•Stroke                    •Uremia
•Vascular malformations    •Hepatic encephalopathy
•Meningitis/encephalitis   •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
           with 1st 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:
     •   (1)   evidence of a structural lesion
     •   (2)   EEG abnormalities
     •   (3)   partial type seizure
     •   (4)   family history of seizures
     •   (5)   focal abnormalities on exam
• Most patients with one or more of these risk
  factors should be treated
       Antiepileptic Drugs of Choice


               Primary Generalized                                  Atypical Absence,
               Tonic-Clonic          Partial         Absence        Myoclonic, Atonic


First-Line     Valproic acid         Carbamazepine   Ethosuximide   Valproic acid
               Carbamezepine         Phenytoin       Valproate
               Phenytoin




Alternatives   Lamotrigine           Gabapentin      Lamotrigine    Lamotrigine
               Primidone             Topiramate      Clonazepam     Topiramate
               Phenobarbital         Tiagabine                      Clonazepam
                                     Primidone                      Felbamate
                                     Phenobarbital
       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
             Side effects
Guidelines
    Neurologic Consultation (NEJM 2001)

•   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

				
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