What should you know about intracranial hypertension?

The skull is a rigid space containing the brain, blood and cerebrospinal fluid. Extra fluid, swelling, bleeding or a mass can raise pressure within that space. Symptoms may include a persistent or worsening headache, nausea, vomiting, blurred or double vision, brief visual dimming, pulsating noise in the ears, sleepiness or difficulty thinking. A headache alone does not establish the diagnosis. Clinicians may examine the eyes for optic-nerve swelling and arrange brain imaging or other tests to identify the cause.

Arrange prompt medical assessment for new persistent headaches with visual changes, vomiting or unusual drowsiness. Bring a list of medicines and mention recent head injury, infection, pregnancy, weight change or previous neurological problems. Treatment is directed at the cause and may involve hospital monitoring, medicines, drainage of fluid or a procedure. Do not drive if vision is impaired or you feel confused. Conditions such as [Obesity](/conditions/obesity/) and [Obstructive Sleep Apnoea](/conditions/obstructive-sleep-apnoea/) may be relevant to the clinician’s assessment.

Call emergency services for a sudden severe headache, new weakness or numbness, trouble speaking, seizure, collapse, unequal pupils, repeated vomiting, marked confusion or rapidly worsening vision. These signs can reflect dangerous pressure or another emergency such as [Stroke](/conditions/stroke/). Do not wait for symptoms to settle or attempt to manage severe neurological changes at home.

What might be causing the pressure? How will my vision and optic nerves be checked? Which scan or test is appropriate? What symptoms mean I should return immediately? Could any current medicine be contributing?