creation date: 2026-01-12 11:28
tags: Workups
Seizure
Background
Seizures are a sudden change in behaviour due to electrical hypersynchronization of neurons in the cerebral cortex.
Seizures can either be acute symptomatic seizures (provoked), which is a seizure that occurs at the time of a sytemic insult or in close association with a brain insult, or epileptic (unprovoked), which are discussed in more detail separately.
Causes
Seizures can be due to virtually any acute insult.
Acute brain injury
- Cerebrovascular disorders
- Acute ischemic stroke or hemorrhagic stroke
- Subdural hematoma
- Subarachnoid hemorrhage
- Cerebral venous thrombosis
- Posterior reversible encephalopathy syndrome
- Acute traumatic brain injury
- Eclampsia
- Hypoxic-ischemic injury
- Brain abscess
- Meningitis or encephalitis
Acute systemic disorder
- Hypo/hyperglycemia
- Hyponatremia
- Hypocalcemia
- Hypomagnesemia
- Uremia
- Hyperthyroidism
- Disorders of porphyrin metabolism
- Withdrawal states (particularly alcohol or benzodiazepine)
- Drug intoxication, poisoning, and overdose
- Global cerebral hypoperfusion
Epileptic (unprovoked)
- Genetic
- Structural (lesions)
- Metabolic
- Immune
- Infectious
Differential Diagnosis
- Syncope
- Transient ischemic attack (particularly in older adults)
- Migraine
- Panic attack and anxiety
- Psychogenic nonepileptic seizure
- Transient global amnesia (rare before the age of 50 years)
- Narcolepsy with cataplexy
- Paroxysmal movement disorders, including multifocal myoclonus from toxic and metabolic disorders
Initial Evaluation
The goals of evaluation are to determine:
- If seizure or nonepileptic
- Was the seizure provoked or unprovoked
- Underlying pathology behind unprovoked seizure
- Risk of recurrence
History
History should include:
- Whether seizure was witnessed
- The lead up to the seizure, including possible precipitants or triggers
- Characteristics of movement if there were any
- Prodromes and post-ictal period
- History of seizures, medication use, substance use
- History of malignancy or immunosuppresion
- For patients with known epilepsy, whether there has been changes to medication use
Physical Exam
Physical includes:
- Neurologic exam with attention to focal deficit and eye movements
- Examination of the tongue
Investigations
Laboratory studies
Standard evaluation following first seizure are:
- POC glucose
- Serum electrolytes (including extended)
- Serum lactate
- CBC
- Renal function
- Liver function
- Urinalysis
Toxicology screen may be indicated if suspected.
Additional evaluation
- ECG - for any loss of consciousness
- Neuroimaging - indicated for all patients for new onset seizures (urgent noncontrast CT if intracranial lesion is suspected; otherwise outpatient MRI)
- EEG - supports diagnosis, especially if not obvious
- Lumbar puncture - if acute infectious process is suspected