Idiopathic Intracranial Hypertension
What is idiopathic intracranial hypertension?
Idiopathic intracranial hypertension (IIH) is high pressure in the spaces around the brain and spinal cord, which are protected and nourished by cerebrospinal fluid (CSF). Such pressure increase may result from a number of causes, but in people with IIH, the cause is not known. IIH can cause vision problems such as double vision and even temporary blindness.
What raises the risk of developing idiopathic intracranial hypertension?
IIH is most common in women ages 20-50; about 5 to 10 percent experience disabling vision loss. Obesity is a major risk factor. Even if you are overweight but not obese, a recent gain of 5 to 15 percent of your total body weight can increase your chance of developing IIH.
What are the symptoms of idiopathic intracranial hypertension?
An increase in pressure around the brain and spinal cord can cause:
- Vision loss (blind spots, impaired peripheral vision, double vision, short episodes of blindness, and sometimes permanent vision loss)
- Ringing in the ears
- Neck and shoulder pain
How is idiopathic intracranial hypertension diagnosed?
Your doctor will take a complete medical history and perform a physical exam as well as a neurological exam. Some people with IIH have weakened muscles near the temples which normally help turn your eyes outward. As a result, your eyes may turn inward, causing double vision. Your doctor may perform these tests:
- Vision tests. A comprehensive dilated eye exam can spot signs of papilledema (swelling and damage to the optic nerve). Visual field testing can be used to assess your peripheral vision.
- Brain imaging. Scans such as MRI or CT imaging may be completed to rule out a brain tumor or other cause of your symptoms.
- Lumbar puncture (spinal tap). This test is done to measure CSF pressure and to collect a small amount of CSF for analysis, to look for the cause of the pressure increase. A spinal tap may also temporarily reduce CSF pressure and relieve your symptoms.
Can idiopathic intracranial hypertension be treated?
IIH usually improves with treatment, and in some cases goes away and then comes back. If tests show you have IIH, your doctor will monitor your vision regularly. He or she may also recommend:
- Weight loss. If you are overweight, it’s very important that you lose weight through healthy eating, restricting salt, and exercising. Losing 5 to 10 percent of your body weight may be enough to help you feel better. If you are very obese and cannot lose the weight through these means, your doctor may recommend weight loss surgery.
- Medication. While you are trying to lose weight, you may also be prescribed acetazolamide, a medication that reduces CSF production.
- Surgery. If your IIH is quickly getting worse and the other steps you are taking aren’t working well, you may need surgery to relieve pressure on the optic nerve. Inserting a tube called a shunt to drain excess CSF from the brain can lower intracranial pressure. With another procedure—optic nerve sheath fenestration—the surgeon relieves pressure on the optic nerve by creating a small window into its covering, just behind the eyeball. However, most people with IIH do not need surgery.