Differential Diagnosis of Paroxysmal Disorders – adapted from Tintinalli’s Emergency Medicine: A Comprehensive Guide

  • CNS
    • Seizure
    • Syncope
    • Migraines
    • TIAs
  • Neuromuscular
    • Movement disorders (dystonia, myoclonic jerks, chorea, tremor, tics)
  • Psychiatric
    • Pseudoseizure
    • Narcolepsy
    • Cataplexy (drop attacks)
    • Hyperventilation syndrome


Etiology of seizures

D rugs                 – side-effects, overdose, illicit

I nfection         – CNS, febrile type

M etabolic       – ↑/↓glucose, ↑/↓sodium, hyperosmolar, uremia, hepatic failure hypocalcemia, hypomagnesemia

W ithdrawal     – EtOH – delirium tremens

I ntracranial hemorrhage

T rauma

S tructural        – congenital, vascular, mass, degenerative

S leep deprivation

P regnancy eclampsia


Generalized – loss of consciousness, whole cerebral cortex activation (tonic-clonic, tonic, clonic, myoclonic, atonic, absence, febrile)

Partial – no loss of consciousness, localized activation of cortex (simple partial, complex partial, *may have 20 generalization)


Most patients present to the emergency room after their “seizure” has finished.  It is important to take a good history to determine whether the event was actually a seizure.  Information may be gathered from the patient themselves, as well as descriptions of the patient’s attack from those who witnessed the event.

  • HPI
    • Preceding symptoms: aura
    • Event: onset, activity, sphincter control, duration
    • Postictal: confusion, lethargy, recovery, recollection of event, Todd’s paralysis
    • ? ingestions, ?precipitants, ?extent of trauma, ?focality
  • PMHx
    • Known seizure disorder – diagnosis, prior seizures, baseline, triggers, antiepileptics (missed or changes in Rx)
    • Infection
    • Trauma
    • Sleep
    • Metabolic
    • Unknown seizure disorder – school/work, injuries unexplained, sphincter control
  • Drugs – EtOH, illicit Rx, withdrawal
  • Pregnancy
  • FHx

Physical Exam

  • Vitals (especially temperature and glucose)
  • Look for injuries (orthopedic, oral)
  • Look for infection
  • Neurological examination
  • Dermatologic exam (especially in pediatrics – look for ash leaf spots, café au lait spots, port wine stains…)

Investigations – use clinical judgement based on patient’s presentation and history

  • Blood glucose
  • CBCD
  • Electrolytes, BUN, creatinine, calcium, magnesium, anion gap, lactate, prolactin (will be elevated after seizure, sometimes used if not sure if event was a seizure)
  • Beta-HCG
  • ABG, U/A, LP
  • Toxicology
  • Anticonvulsant levels
  • CK – for rhabdomyolysis (urine shows Hgb but no RBC)
  • CT head if trauma, suspected intracranial hemorrhage, suspected structural lesion in first time seizure, prolonged altered mental status, focal neurological deficit, anticoagulated patient, HIV/Cancer patients, ongoing H/A, change in seizure pattern
  • If infection – may require full septic w/u (LP, cultures, etc)
  • EEG – most likely to be done as an outpatient
  • MRI – in consultation with neurology
  • Don’t forget to investigate for suspected injuries as a result of the seizure!


  • If the patient is seizing
    • Move to safe place
    • Turn to side (recovery position) if possible
    • Observation for specific activity and progression and duration
    • Prepare to assess/monitor once seizure subsides (ABC’s)
    • Consider treatment if patient is in status
  • Postictal
    • Seizure precautions
    • ABC’s and monitors, chemstrip, O2
    • Benzodiazepines may be used to prevent further seizures
    • Consider anticonvulsant therapy
      • Phenytoin (Dilantin) 300-600mg PO tid
      • Phenobarbital 60-200mg PO daily
      • Valproic acid (Epival) 15-60mg/kg daily divided bid or tid
      • Carbamazepine (Tegretol)  400-1200mg daily divided tid/qid
  • Status epilepticus – 30+min of active seizing or no recovery/consciousness between
    • IV line, O2, monitors
    • Consider intubation
    • Benzodiazepines (diazepam 10-20mg IV, or lorazepam 4-8mg IV)
    • Phenytoin 18-20mg/kg IV @ 25mg/min

In first time seizures with normal EEGs approximately 25% will seize again within 2 years.  In first time seizures with abnormal EEGs, it rises to 50%.  Also mortality is unchanged with medication.


  • No driving for 1 year
  • Warn about swimming and heights

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