Idiopathic Intracranial Hypertension

What is it?

Idiopathic Intracranial Hypertension, or IIH, is when the pressure of fluid around a person’s brain is too high and the doctors don’t know why.

  • Idiopathic means no one knows what is causing it
  • Intracranial means inside the skull
  • Hypertension means pressure

What causes it?

Nobody knows what causes IIH.  If doctors can work out what has caused the pressure then this is called Secondary IH, or SIH for short. If someone has SIH the pressure can be fixed more easily.

What does this mean?

  • People with IIH will have a bad headache and they will feel dizzy, tired and sick.
  • People with IIH may have problems with their eyes. It can make their vision blurred and sometimes they may see blobs and squiggly lines. If the pressure is really high it can cause blindness.
  • People with IIH may look just like everyone else.  It can be difficult for everyone in the family to understand how they are feeling.
  • People with IIH may feel fed up or worried, and have to do things more slowly than other people.
  • People with IIH may not be able to run around and play.

What treatment is there?

  • Sometimes IIH can go away all by itself.
  • People with IIH sometimes have medicine to keep the pressure away.
  • People with IIH will see an ophthalmologist (a special eye doctor) to help them keep their eyes healthy
  • People with IIH sometimes have a shunt to stop the pressure. This is a tube to drain fluid from around the brain.
  • People with IIH have tests to find out more about the pressure. One test is a lumbar puncture. Doctors put a needle into the bottom of the person’s back to see what the pressure is. Another test is when doctors put a little wire into the person’s head. The wire stays in their head for a day or two and a machine tells the doctors what the pressure is.


This information has been approved by IIH UK, March 2015

< Back