Idiopathic Intracranial Hypertension/Pseudotumor Cerebri

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What is idiopathic intracranial hypertension/pseudotumor cerebri?

Idiopathic intracranial hypertension (IIH), also called pseudotumor cerebri, is a condition in which there is high pressure in the fluid surrounding your brain, spinal cord, and optic nerves. This can cause headaches and problems with vision. Although the cause, or causes, of the condition is not known, we know much about the condition itself.

Do I have a tumor?

Patients with pseudotumor cerebri do not have a tumor. A brain tumor may also cause increased intracranial pressure, which is why this condition is called a “pseudotumor” - it can cause symptoms like a real tumor, but the tests do not show any tumors (pseudo- means “false,” so pseudotumor means “false tumor”).

Who can get IIH?

IIH can affect anyone, but is more common in women (90%) than men (10%). It is more common in teenagers and young women but can affect people of any age. 

What causes IIH?

We do not know what causes IIH. However, there is a clear association to being overweight. Not all overweight or obese people develop this condition. This likely means that there are unique features that predispose some people to develop IIH that we have yet to discover. Medical studies have shown that recent weight gain can cause IIH, and that weight loss alone can achieve remission in some cases. There is ongoing research into the cause/causes of IIH.

How does IIH affect me?

Not everyone will develop all the symptoms of IIH. The most common symptoms of IIH include:

  • Headaches

    • Headache is the most common symptom, although not everybody with IIH has headaches. 

  • Brief visual changes such as dimming, blurring or graying of vision

    • These changes only last for a few seconds (often with bending or stooping).

  • Sounds of a heartbeat-like noise in the ears (pulsatile or pulse-synchronous tinnitus)

  • Neck pain

Less common symptoms include:

  • Double vision

  • Memory problems

  • Nerve or back pain

  • Dizziness

    In severe cases, IIH can cause severe peripheral vision loss and blurred central vision. If left untreated, there is a high risk of permanent disabling loss of vision.

How is IIH diagnosed?

There are three important steps that must be done in order to diagnose IIH:

  • A complete eye exam must be performed, including special tests on your visual field and dilation of the pupils to look for swelling of the optic nerves caused by high pressure in the brain (papilledema).

Courtesy of Dr. Valerie Biousse, M.D.

Normal optic nerve (left) and papilledema (right). The normal optic nerve looks like a flat orange-yellow disc. In papilledema, the edges of the disc become blurred and fuzzy, and the entire nerve eventually swells.

  • Brain scans by computed tomography (CT) or magnetic resonance imaging (MRI) must show that there is no tumor, blood clot, or other cause for the suspected high pressure. Sometimes the brain scan report will say that there are changes to the pituitary gland or fluid around the optic nerve that suggests IIH. These can be useful clues for your doctor to diagnose IIH but cannot replace a lumbar puncture with opening pressure.

  • A lumbar puncture (also called a spinal tap) must be performed to confirm a high pressure and a normal spinal fluid (CSF). The lumbar puncture must be performed with you relaxed and lying on your side for the reading to be accurate.

Why do I need to see a neuro-ophthalmologist?

Neuro-ophthalmologists are the experts with the most experience and knowledge about IIH. Though many neurologists and ophthalmologists may also see and manage people with IIH, neuro-ophthalmologists receive specific training to help take care of all forms of IIH. Many specialists may be involved in your treatment:

  • Neuro-ophthalmologists evaluate and guide the medical and/or surgical treatment.

  • Ophthalmologists or neuro-ophthalmologists monitor your vision by performing dilated eye exams, visual field testing, photos and/or a special imaging test called an optical coherence tomography (OCT). Some ophthalmologists or neuro-ophthalmologists are specifically trained to perform optic nerve surgery, which may be one of several alternatives for management of severe cases of IIH. 

  • Neurologists may help coordinate the testing for diagnosing IIH and help treat headaches that are not caused by high pressure.

  • Neurosurgeons may be involved if surgery is necessary to control the high pressure.

How is IIH treated?

Most people with IIH are treated with medications and are encouraged to lose weight. Less than 1 out of 10 people (< 10%) with IIH will have surgical treatment.

Very few people become blind from IIH and most people recover if they are treated early. Surgery is needed if medical treatment and weight loss does not stop the visual loss. In very rare cases, blindness may occur even with correctly administered medications and surgery.

Surgical treatments

Surgery is recommended when vision is getting worse from high pressure despite aggressive treatment with medications. Because surgery has small but potentially dangerous risks to your life and/or vision, surgery for IIH is not recommended when your vision is good. The goal of surgery is to release pressure around the optic nerves. There are three main types:

  1. Shunt surgery:  a neurosurgeon places one end of a flexible tube into one of the normal fluid-filled spaces in your brain (ventricle) or into your spine (lumbar) and the other end into another part of your body, such as your abdomen (peritoneum).

  2. Venous stenting:  A neurovascular surgeon inserts a device that holds open a vein that drains blood from the brain. It is a newer technique for lowering brain pressure. There are risks for this procedure, so it is still not used commonly as a treatment for IIH.

  3. Optic nerve sheath fenestration:  an orbital surgeon creates a small window in the lining (sheath) around your optic nerve to allow the fluid to drain behind your eye.

Main Treatments of IIH

Do I need treatment?

If you have no significant headaches or vision loss, no treatment may be necessary (though weight reduction is always a good idea to prevent the disease from worsening). The decision to treat or not treat is based on the clarity of your vision (visual acuity), peripheral vision (visual fields), presence of papilledema, and whether or not you have headaches.

Weight loss is hard to do. How much weight do I need to lose?

Weight loss can be a sensitive issue for both the doctor and the patient. Weight loss is difficult to do and maintaining a lower weight long-term is challenging. 9 out of 10 people with IIH are overweight, and weight loss can be a very effective treatment. Weight reduction programs that include lifestyle modification and a diet low in sodium have been shown to be effective in treating IIH. The goal is weight loss of 5-10% of your starting weight; for example, someone with a starting weight of 250 lbs (113 kg) would have a target weight loss of 12.5 lbs-25 lbs (5.6 kg-11.3 kg). In some cases, weight management (bariatric) surgery may be helpful.

What medications are used for treating IIH?

Diamox (acetazolamide) is the most common medication used for treating IIH. It is thought to lower brain pressure by reducing fluid (cerebrospinal fluid, or CSF) production. Research shows that Diamox significantly improves vision, papilledema, quality of life and CSF pressure.

Common side-effects of Diamox include:

  • Tingling of fingers and toes

  • Loss of appetite

  • Metallic taste when drinking fizzy drinks (carbonated beverages)

  • Tiredness (fatigue)

  • Kidney stones may occur in rare cases (2-3%)

If you are not able to take acetazolamide, your doctor may prescribe other medications such as Lasix (furosemide), Topamax (topiramate), Zonegran (zonisamide), and Neptazane (methzolamide).

What medications help for headache in IIH?

There are no medications specifically designed for IIH-related headaches. Over-the-counter analgesics such as non-steroidal anti-inflammatory drugs (NSAIDS) and/or migraine medications may be helpful if you have headaches even after the IIH treatment is successful.

Using pain medications >2-3 days per week for more than a few months can make you dependent on the medications, so that when you don’t take the pain medications you get a withdrawal headache (medication-overuse headache). This is a background daily headache that may be confused with high pressure and can make the severe headaches worse. Withdrawal from these medications is helpful.

When will the IIH go away? Can the IIH come back?

IIH may go away over months to years or it may be a lifelong medical problem. IIH can return, and is linked to regaining weight.

Will I need another spinal tap in the future?

Generally not, unless there is a new problem. IIH is rarely treated with multiple spinal taps.

Does IIH run in families?

IIH may run in some families (approximately 5%).


Copyright © 2020. North American Neuro-Ophthalmology Society. All rights reserved.

This information was developed collaboratively by the Patient Information Committee of the North American Neuro-Ophthalmology Society. This has been written by neuro-ophthalmologists and has been edited, updated, and peer-reviewed by multiple neuro-ophthalmologists. The views expressed in this brochure are of the contributors and not their employers or other organizations. Please note we have made every effort to ensure the content of this is correct at time of publication, but remember that information about the condition and drugs may change. Major revisions are performed on a periodic basis.

This information is produced and made available “as is” without warranty and for informational and educational purposes only and do not constitute, and should not be used as a substitute for, medical advice, diagnosis, or treatment. Patients and other members of the general public should always seek the advice of a physician or other qualified healthcare professional regarding personal health or medical conditions.

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