Seizure, Adult

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

• 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