Seizures in intensive care are often different from seizures seen in an outpatient epilepsy clinic. They can be caused by acute brain injury, systemic illness, organ failure, medication effects or withdrawal, and many are non-convulsive.
Not every ICU seizure means epilepsy
A seizure during an acute stroke, infection, metabolic crisis or toxic exposure may be an acute symptomatic seizure rather than evidence of an enduring epileptic disorder.
This distinction affects prognosis, long-term treatment and how the event is explained to patients and families.
Common neurological causes
Stroke, intracranial haemorrhage, traumatic brain injury, brain tumour, encephalitis, meningitis and neurosurgery can all provoke acute seizures.
Some of these conditions also increase the longer-term risk of later unprovoked seizures and epilepsy.
Systemic illness can provoke seizures too
Severe abnormalities of glucose, sodium, calcium or other metabolic parameters can provoke seizures. Liver or kidney failure, sepsis and drug toxicity can also contribute.
Treating the underlying physiological disturbance can be as important as giving an antiseizure medicine.
Sedation hides clinical signs
Ventilated or heavily sedated patients may have little visible movement during a seizure.
Neuromuscular blocking drugs can eliminate motor signs completely while cortical seizure activity continues, making EEG essential when seizures are suspected.
Status epilepticus in intensive care
Status epilepticus is a common reason for neurological ICU admission and can itself create respiratory, cardiovascular, metabolic and systemic complications.
Refractory cases may require anaesthetic treatment, mechanical ventilation and continuous EEG.
The danger of diagnostic anchoring
Abnormal movements in intensive care are not always seizures. Shivering, tremor, rigors, posturing, myoclonus and medication-related movements can mimic epilepsy.
Video-EEG can be crucial when the distinction changes management.
Recovery and prognosis depend on cause
The outcome after an ICU seizure is often determined more by the underlying brain or systemic illness than by the seizure alone.
This is particularly important when discussing prognosis after stroke, infection, trauma or cardiac arrest.
Related reading
Sources and further reading
- Status epilepticus: what’s new for the intensivist — 2024
- Acute symptomatic seizures and systemic illness
- Continuous EEG consensus statement — indications
Evidence checked: September 2026.