Let's start with the name:
Idiopathic Intracranial Hypertension is a mouthful so mostly we say "IIH".
(This is basically the same thing as pseudotumor cerebri which is more of an old fashioned term, that I do not like to use because many patients get confused and just hear the "tumor" part. - Let me be clear this is not a tumor.)
Idiopathic- for reasons we cannot explain
Intracranial- inside the head
Hypertension- high pressure
IIH - for reasons we cannot explain the fluid inside the head has too high of a pressure.
Pressure in the head can cause various symptoms.
Headaches are prominent, but sometimes patients feel neck or back pains, too since all those are connected to the same fluid.
This can create a hearing symptom since your ears are also located inside the head. Patients are hearing the blood flow through these narrow veins. It is described as whooshing or thumping. If you've ever heard a heartbeat on an ultrasound then you might recognize this sound.
The eyes connect to the brain through the optic nerve
So, that brain fluid pressure can extend all the way up the nerve and create pressure on the back of the eye. If that pressure creates swelling in the tip of the nerve, we call that swelling papilledema.
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| Normal Papilledema Note the blurriness of the nerve edges in papilledema. |
Papilledema can cause vision changes. Sometimes it can cause spots in the vision or decreased peripheral vision. It can also cause blackouts of the vision that last just a moment, especially with position changes, like if you bend over and stand up too quickly.
IIH is diagnosed by excluding other causes of pressure. There should be a brain scan to rule out a tumor or any other mass or clot that could cause pressure to build up.
Then patients will often have a lumbar puncture (also called spinal tap). This procedure is very similar to an epidural which is given during labor and delivery, but instead of injecting medicine in, the fluid will be drained out. Checking this fluid helps rule out inflammatory or infectious disease and can allow the pressure to be measured right out of the spine. (Of course we are really interested in the pressure of the head, but there is no safe place to put a needle in the head. Since it is all connected, the patient lays flat and we can accurately measure pressure in the lower back.)
If the tests all come back negative except for signs of pressure then we can confirm the diagnosis of IIH.
IIH is treatable. Most patients are treated with Diamox (acetazolamide) but sometimes Topamax (topiramate) works, too.
We don't know what the connection might be, but patients with IIH are usually overweight. So, sometimes weight loss can make an improvement.
In summary, IIH is a condition of pressure in the head. Symptoms include headache, vision changes and certain hearing symptoms. Diagnosis is based on eye exam, brain scans and lumbar puncture. Treatment is usually with medication and sometimes weight loss.