Seizure – CMAJ 2003

Seizure:  Transient neurological dysfunction caused by xs activity of cortical neurons, resulting in paroxysmal alteration of behaviour &/or EEG changes
Epilepsy: Chronic condition characterized by ≥ 2 unprovoked Sz
Status Epilepticus: Unremitting Sz >5min or successive Sz w/o return to a baseline state

  • Complication include neuronal death, rhabdomyolysis, lactic acidosis

Nonconvulsive Status epilepticus: alt of awareness (confusion to coma) w/o motor manifestations. Dx with EEG

S/Sx:
  1. Ictus (sec to mins): Salivation, cyanosis, tongue biting, incontinence, loud cry, head + eye roll
    • tonic and/or clonic movements of head, eyes, trunk, or extrem.
  2. Aura (sec to mins) – Temporal: behaviour (olfactory, gustafactory), unusual behavior, oral / appendicular automastisms
  3. Post-ictus (mins to hr): limb pain, h/a, drowsiness / lethargy, focal weakness, slowly resolving period of confusion, disorientation
    • may have Todd’s paralysis – focal neurologic deficits

1 In a patient having a seizure:
a) Ensure proper airway control (e.g., oropharyngeal airway or nasal trumpet, lateral decubitus to prevent aspiration).
b) Use drugs (e.g., benzodiazepines, phenytoin) promptly to stop the seizure, even before the etiology is confirmed.
c) Rule out reversible metabolic causes in a timely fashion (e.g., hypoglycemia, hypoxia, heat stroke, electrolytes abnormalities).

5 In a patient with a previously known seizure disorder, who presents with a seizure or a change in the pattern of seizures:
a) Assess by history the factors that may affect the primary seizure disorder (e.g., medication compliance, alcohol use, lifestyle, recent changes in medications [not just antiepileptic medications], other illnesses).
b) Include other causes of seizure in the differential diagnosis. (Not all seizures are caused by epilepsy.)

Acute Management:
  1. Secure airway (nasal trumpet, oropharyngeal airway), lateral decubitus
  2. Give O2
  3. Rectal diazepam
  4. Secure IV access
  5. Acutely r/o hypoglycemia, hypoxia, lytes (hyponatremia), heat stroke, EtOH withdrawal, fever
Status Epilepticus
  1. Consult neurology
  2. Place pt in semi-prone position to decrease risk of aspiration
  3. Oral airway or if prolonged, endotracheal intubation
  4. IV access, start NS infusion
  5. STAT labs: Glc, Na, Ca, serum & urine toxicology screen, anticonvulsant levels
  6. Thiamine 100mg IV prior to dextrose to prevent exacerb of Wernicke’s encephalopathy
  7. Dextrose 50g IV push
  8. Antiepileptics
    1. Lorazepam (Ativan) 0.1mg/kg at 2mg / min (2-4mg IV push)or Diazepam 0.2mg/kg at 5mg/min
    2. Phenytoin 20mg/kg at 50mg/min (1-1.5g IV over 20min)
    3. If still not working, Intubate, ICU +
    4. Phenobarbital 20mg/ kg at 50-75 mg/min (1-1.5g IV over 30min)
    5. General anesthesia with midazolam / propofol
Etiologies (other causes of Sz besides epiplepsy):
  • Alcohol withdrawal, illicit drugs, meds (b-lactams, bupropion, tramadol, metronidazole, meperidine, CsA, antidep., clozapine can lower Sz threshold)
  • Brain Tumor or Penetrating trauma (mild-mod head trauma followed by a tonic-clonic Sz)
  • Cerebrovascular dz: subdural hematomas, hypertensive encephalopathy,
  • Degenerative disorders of the CNS: Alzheimer’s, metabolic encephalopathy, meningitis (CNS infection)
  • Electrolyte (hyponatremia) & other metabolic: uremia, liver failure, hypoglycemia
  • Febrile Sz in early childhood & Sleep deprivation

2 In a patient presenting with an ill-defined episode (e.g., fits, spells, turns), take a history to distinguish a seizure from other events

ddx of Convulsions
  • Syncope
  • Pseudoseizure
  • Hyperventilation
  • Panic disorder
  • TIA
  • Hypoglycemia
  • Movement disorder
  • Alcoholic blackouts
  • Migraines – confusional, vertebrobasilar
  • Narcolepsy – cataplexy
Hx: Sz pt usually w/o recollection, must talk to witnesses & get collateral hx
  1. Unusual behavior before seizure (aura)
  2. Type and pattern of abnl movements, incl. head turning, eye deviation (gaze preference usually away from Sz focus)
  3. LOC?
  4. HPI: recent illness, head trauma, sleep deprivation, medications
  5. PMH: prior Sz or + FHx, prior meningitis / encephalitis, prior stroke / head trauma
  6. Meds/ illicit drugs, EtOH
Features Sz Syncope
Aura Unusual behavior / automatisms Diaphoresis, nausea, tunnel vision
Convulsions Variable duration <10sec
Post-ictal state Yes No
Other clues Tongue biting, incontinence Skin pallor, clamminess
Nonepileptic Sz (psychogenic)
  • side-to-side head turning, asymmetric large-amplitude limb movements, diffuse twitching w/o LOC, and crying or talking during eventT2.medium

3 In a patient presenting with a seizure, take an appropriate history to direct the investigation (e.g., do not overinvestigate; a stable known disorder may require only a drug-level measurement, while new or changing seizures may require an extensive work-up).

Ix
  • Lab: Full electrolytes, BUN, Cr, glc, LFTs, tox screen, medication levels
  • ECG
  • EEG (abn spikes, polyspike d/c, spike-wave complexes) – support Dx but doesn’t r/o Sz
    • sleep deprived EEG ↑ dx yield
    • video monitoring may help with nonepileptic Sz
  • Neuroimaging: MRI >CT, to r/o structural abnormalities
    • If <2yo, focal onset, continuous despite 1st line meds
  • LP after r/o space-occupying lesion –
    • if suspect meningitis (fever, WBC, nuchal rigidity) or encephalitis &
    • in ALL HIV + pt

4 In all patients presenting with a seizure, examine carefully for focal neurologic findings.

PEx
  • skin – neuroectodermal disorders: neurofibromatosis, tuberous sclerosis
  • Neurolgoical exam: focal abnormalities due to underlying structural abnormality

6 In the ongoing care of a patient with a stable seizure disorder:
a) Regularly inquire about compliance (with medication and lifestyle measures). side effects of anticonvulsant medication, and the impact of the disorder and its treatment on the patient’s life (e.g., on driving, when seizures occur at work or with friends).
b) Monitor for complications of the anticonvulsant medication (e.g., hematologic complications, osteoporosis).
c) Modify management of other health issues taking into account the anticonvulsant medication (e.g., in prescribing antibiotics, pregnancy).

Antiepileptic drug
  • reserved for pt w/ underlying structural abnormality on brain imagingor
  • Idiopathic / unprovoked Sz +
    • status epilepticus on presentation,
    • focal neurological deficit
    • postictal Todd’s paralysis,
    • abnormal EEG – shows unequivocal epileptic activity
    • Pt or family considers risk of further Sz is unacceptable
  • Start antiepileptic after 2nd unprovoked Sz
    • Use monotherapy when possible
    • The severity of the seizure disorder, not the laboratory numbers, determines the “therapeutic range.” Whatever serum drug level renders the patient seizure free is adequate for that patient, even if it is below the laboratory range.
  • May consider taper / withdrawal if Sz -free (>1yr) and normal EEG
  • First line for all kinds of Sz: Valproate & Lamotrigine (except myoclonic)

T3.medium

 Contraception:
  • Hepatic enz antiepileptic: carbamazepine, phynytoin, phenobarbital, topiramate, primidone
  • ↑ hormone metabolism by 50%
  • NO progesterone only pill, no progesterone IUD
  • Use 50 ug estrogen
  • Double the dose of emergency contraceptive dose (1.5mg levonorgestrel from 0.75mg bid)
Pregnancy
  • Frequency smaller doses – dosing qid ↓ serum surge and has less effect on fetus
  • 5mg/d folic acid
Driving: Provicial Regulation madnates Sz-free duration before being allowed to drive
  • Single, unprovoked: referfor work up (EEG, CT) and no driving x 3mo min
  • After Dx and on med: : May drive if 6mo Sz free on meds
  • Sz at sleep or immediately upon awakening – may drive if no change in 5 years
  • Medication withdrawal: no drive x 3mo from med change
  • Recur after withdrawal: may drive if no Sz x 6mo
  • Long-term withdrawal: may drive any vehicle if no Sz x 5yr
  • Alcohol withdrawal: EtOH free + no Sz x 12 mo
  • Febrile / toxic Sz: no concern if fully recovered.
Counseling:
  • Discuss the Dx, prognosis, triggers
  • Action to take after missed dose or vomiting

References:
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Posted in 81 Seizures, 99 Priority Topics, FM 99 priority topics, Neuro

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