Cerebral Oedema
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Cerebral oedema is dangerous swelling of brain tissue that raises pressure inside the skull. It is a medical emergency, usually managed with corticosteroids such as dexamethasone or osmotic agents.
Key facts
- Cerebral oedema is an abnormal build-up of fluid within brain tissue, raising pressure inside the skull.
- It is a medical emergency: because the skull cannot expand, even modest swelling can compress vital structures rapidly.
- Common triggers include head injury, stroke, brain tumours, severe infections such as bacterial meningitis, and severe metabolic disturbances like low blood sodium.
- Treatment relies on corticosteroids such as dexamethasone and osmotic agents such as mannitol; outcomes depend heavily on how quickly treatment starts.
What cerebral oedema is
Cerebral oedema is an abnormal build-up of fluid within brain tissue, causing pressure to rise inside the skull. Because the skull is a fixed, rigid space, even modest swelling can compress blood vessels and brain structures rapidly. It is a medical emergency, and outcomes depend almost entirely on how quickly treatment begins.
Why it develops
The most common triggers include traumatic head injury, stroke, brain tumours, and severe infections such as bacterial meningitis. High-altitude exposure can also cause it in travellers who ascend too quickly without acclimatising. Metabolic causes, including severe hyponatraemia (low blood sodium), account for a meaningful share of cases as well.
How it is managed
Corticosteroids are a mainstay where oedema surrounds a tumour or is driven by inflammation. Dexamethasone reduces the permeability of blood vessels around the affected tissue, limiting further fluid leakage. Osmotic agents such as mannitol draw excess water out of brain tissue and are used alongside or instead of steroids depending on the underlying cause. Treatment always happens in a hospital setting with close monitoring of neurological status.
When to seek emergency care
Any sudden severe headache, confusion, vomiting, seizure, or loss of consciousness warrants immediate emergency assessment. Cerebral oedema can worsen quickly, and delayed treatment raises the risk of permanent brain injury.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.