Seizure

Background

Types

• Simple (consciousness not impaired)
• Complex (consciousness necessarily impaired)
• Generalized (diffuse brain overactivity)
  • Tonic-clonic, tonic, clonic, myoclonic
  • Absence
  • Atonic
• Partial (specific area in brain affected)
  • Partial seizures with secondary generalization

Precipitants (known seizure disorder)

• Medication noncompliance
• Sleep deprivation
• Infection
• Electrolyte disturbance
• Substance withdrawal (eg alcohol, BZPs)
• Substance intoxication

Causes (First-Time Seizure)

• Idiopathic
• Trauma (recent or remote)
• Intracranial hemorrhage (subdural, epidural, subarachnoid, intraparenchymal)
• Structural CNS abnormalities
  • Vascular lesion (aneurysm, AVM)
  • Mass lesions (primary or metastatic neoplasms)
  • Degenerative neurologic diseases
  • Congenital brain abnormalities
• Infection (meningitis, encephalitis, abscess)
• Metabolic disturbances
  • Hypoglycemia or hyperglycemia
  • Hyponatremia or hypernatremia
  • Hyperosmolar states
  • Uremia
  • Hepatic failure
  • Hypocalcemia, hypomagnesemia (rare)
• Toxins and drugs
  • Cocaine, lidocaine
  • Antidepressants
  • Theophylline
  • Alcohol withdrawal
  • Drug withdrawal
• Eclampsia of pregnancy (may occur up to 8wks postpartum)
• Hypertensive encephalopathy
• Anoxic-ischemic injury (cardiac arrest, severe hypoxemia)

Clinical Features

• Abrupt onset, unprovoked
• Brief duratoin (typically <2min)
• AMS
• Jerking of limbs
• Postictal drowsiness/confusion

Differential Diagnosis

Seizure

• Epileptic seizure
  • First-time seizure
  • Seizure with known seizure disorder
  • Status epilepticus
  • Temporal lobe epilepsy
  • Non-compliance with anti-epileptic medications
  • Hyponatremia
  • INH toxicity
• Non-epileptic seizure
  • Meningitis
  • Encephalitis
  • Brain abscess
  • Intracranial hemorrhage
  • Alcohol withdrawal
  • Benzodiazepine withdrawal
  • Barbiturate withdrawal
  • Baclofen withdrawal
  • Metabolic abnormalities: hyponatremia, hypernatremia, hypocalcemia, hypomagnesemia, hypoglycemia, hyperglycemia, hepatic failure, uremia
  • Eclampsia
  • Neurocysticercosis
  • Posterior reversible encephalopathy syndrome
  • Impact seizure (head trauma)
  • Acute hydrocephalus
  • Arteriovenous malformation
  • Seizure with VP shunt
  • Toxic ingestion (amphetamines, anticholinergics, cocaine, INH, organophosphates, TCA, salicylates, lithium, phenothiazines, bupropion, camphor, clozapine, cyclosporine, fluoroquinolones, imipenem, lead, lidocaine, metronidazole, synthetic cannabinoids, theophylline, Starfruit)
  • Psychogenic nonepileptic seizure (pseudoseizure)
• Intracranial mass
• Syncope
• Hyperventilation syndrome
• Migraine headache
• Movement disorders
• Narcolepsy/cataplexy
• Post-hypoxic myoclonus (Status myoclonicus)

Diagnosis

Physical

• Check for:
  • Head / C-spine injuries
  • Tongue/mouth lacs
    • Sides of tongue (true seizure) more often bitten than tip of tongue (pseudoseizure)
  • Posterior shoulder dislocation
  • Focal deficit (Todd paralysis vs CVA)

Work-Up

Known Seizure Disorder

• Glucose
• Pregnancy test
• Anticonvulsant levels

First-Time Seizure

• Glucose
• CBC
• Chemistry
• Pregnancy test
• Utox
• Head CT
• LP (if SAH or meningitis/encephalitis is suspected)

Indications for Head CT

• First seizure if age older than 40
• History of acute head trauma
• History of malignancy
• Immunocompromised status
• Suspect Intracraneal Process
• History of anticoagulation
• New focal neurologic deficit
• Focal onset before generalization
• Persistently altered mental status

Treatment

Actively Seizing

• Protect pt from injury
  • If possible place pt in left lateral position to reduce risk of aspiration
  • Do not place bite block
  • Ensure clear airway after seizure stops
• Most seizures self resolve. If a patient is actively seizing then any benzodiazepine can be used however Lorazepam IM or IV is generally first line

Status Epilepticus

• Continuous or intermittent seizures >5 min without recovery of consciousness
• Consider secondary causes of seizure (e.g. hyponatremia, INH overdose, ecclampsia)
• Consider EEG to rule-out nonconvulsive status
• Consider prophylactic intubation
• Meds
  • First-Line
    • Lorazepam 2mg IV (up to 0.1mg/kg) OR diazepam 5-10mg IV (up to 0.15mg/kg); AND
    • Phenytoin 20-30mg/kg at 50mg/min OR fosphenytoin 20-30mg/kg/PE at 150mg/min
      • Phenytoin/fosphenytoin contraindicated in pts w/ 2nd or 3rd degree AV block
      • Phenytoin may cause hypotension due to propylene glycol diluent
      • Fosphenytoin may be given IM
  • Refractory
    • Valproic acid 20-40mg/kg at 5mg/kg/min OR
    • Phenobarbital 20mg/kg at 50-75mg/min (be prepared to intubate) OR
    • Propofol 2-5mg/kg, then infusion of 2-10mg/kg/hr OR
    • Midazolam 0.2mg/kg then inusion of 0.05-2mg/kg/hr OR
    • Ketamine 1.5mg/kg then 0.01-0.05mg/kg/hr
      • Contraindicated in pts w/ intracranial masses

No IV

• Midazolam IM 0.2mg/kg OR
• Diazepam PR 0.5-1.0mg/kg (up to 20mg)

History of Seizure

• Identify and correct potential precipitants
• Reload seizure medication if necessary: Seizure Levels and Reloading
  • May use IV vs PO reload at physican discretion

First-Time Seizure

• No treatment necessary if pt has:
  • Normal neuro exam
  • No acute or chronic medical comorbidities
  • Normal diagnostic testing (including normal imaging)
  • Normal mental status
• Treatment generally indicated if seizure due to an identifiable neurologic condition

Special Populations

Neurocysticercosis

• Seizures are typically controlled by antiepileptic monotherapy

Pregnancy

• If pregnancy >20wks and <4wks postpartum consider eclampsia
• Most seizures in pregnancy are not first-time seizures
  • Due to pharmacokinetic drug changes as result of pregnancy or med noncompliance

Disposition

• Typical seizure with known seizure history, normal w/u
  • Discharge after reload
• New onset seizure
  • Discharge (no need to start antiepileptic) with neuro follow up
  • Risk for recurrent seizure is greatest within the first 2 years after a first seizure (21%-45%)
• Status epilepticus
  • Admit ICU

See Also

• Seizure Levels and Reloading
• Seizure (Peds)
• Febrile Seizure
• Anticonvulsants