Seizure, Adult

Basics

Description

  • Generalized seizures:
    • Abnormal neuronal activity in both cerebral hemispheres
    • Classically tonic–clonic (grand mal) seizures: Impaired awareness, muscle rigidity (tonic), rhythmic jerking movements (clonic)
    • Absence (petit mal) seizures: Altered consciousness but no postural tone change; can have brief twitches (myoclonus)
  • Focal (partial) seizures:
    • Usually involves one cerebral hemisphere preserving consciousness, may spread to involve both hemispheres and cause altered sensorium
    • More likely to be secondary to localized structural lesion
    • No longer classified as simple partial (i.e., Jacksonian) and complex partial (consciousness or mentation affected)
  • Status epilepticus:
    • Seizure lasting longer than 5 min (classically defined as at least 30 min) or recurrent seizures without return to baseline mental status between events
    • Nonconvulsive status epilepticus may present in >9% of hospitalized patients with prolonged decreased mental status
    • Life-threatening emergency, mortality approaching 30% if seizure lasts >1 hr
    • At least one-half of patients presenting to ED in status do not have a history of seizures
  • Special populations:
    • HIV: Mass lesions, encephalopathy, herpes zoster, toxoplasmosis, Cryptococcus, neurosyphilis, meningitis
    • Neurocysticercosis: CNS infection of tapeworm Taenia solium, MCC of provoked seizures in developing world
    • Pregnancy beyond 20 wk of gestation: Eclampsia (hypertension, edema, proteinuria, seizures)
    • Alcohol withdrawal seizures: Peak within 24 hr of last drink, rarely progress to status epilepticus
  • 8–10% lifetime risk of symptomatic seizure
  • Patients with a single seizure have a 35% risk of recurrent seizure within 5 yr
  • In 2011:
    • 1.6 million ED visits for seizures
    • 400,000 with new-onset seizures

Pediatric Considerations
Simple febrile seizures (self-limited and benign)
  • Age 6 mo–6 yr
  • Generalized convulsions
  • Typically lasts <15 min
  • Do not recur within 24 hr
  • No CNS infection or other neurologic disease

Etiology

  • Hypoxia
  • Hypertensive encephalopathy
  • Eclampsia
  • Infection:
    • Meningitis
    • Abscess
    • Encephalitis
  • Vascular:
    • Ischemic stroke
    • Hemorrhagic stroke
    • Subdural hematoma
    • Epidural hematoma
    • Subarachnoid hemorrhage
    • Arteriovenous malformation
  • Structural:
    • Primary or metastatic neoplasm
    • Degenerative disease (e.g., multiple sclerosis)
    • Lesion from previous trauma
  • Metabolic:
    • Electrolytes
    • Hypernatremia
    • Hyponatremia
    • Hypocalcemia
    • Hypo/hyperglycemia
    • Uremia
  • Toxins/drugs:
    • Lidocaine
    • Tricyclic antidepressants
    • Salicylates
    • Isoniazid
    • Cocaine
    • Alcohol withdrawal
    • Benzodiazepine withdrawal
  • Congenital abnormalities
  • Idiopathic
  • Trauma

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