What is idiopathic intracranial hypertension?
Idiopathic intracranial hypertension, or IIH, is the result of an increased pressure within the spaces that surround the brain and spinal cord. Normally, the cerebrospinal fluid (CSF) fills up this space. The CSF is responsible for protecting the brain from trauma, and provide it with nutrition. In addition, it also removes the toxins and waste.
What causes idiopathic intracranial hypertension?
Intracranial hypertension can be either acute or chronic, depending upon how long the disease has lingered.
Typically, in chronic or longstanding IIH, the increased pressure may cause a swelling of the optic nerve. This swelling of the optic nerve is called papilledema.
Chronic increase in CSF pressure may be a result of:
- Brain tumor
- Blood clot in the brain
- Excessive intake of vitamin A
- Use of tetracycline
- Most commonly, without a specific reason
When there is no detectable cause for the increased CSF pressure, the condition is known as idiopathic intracranial hypertension.
What are the symptoms of idiopathic intracranial hypertension?
Very often, the symptoms of IIH are non specific. The most common symptoms include:
- Headaches
- Vision loss
- Poor peripheral vision
- Double vision
- Squint or deviation of eyes
- Transient episodes of blindness
- In addition, some patients report a ringing in the ears and pain in the neck and shoulders.
In fact, the symptoms of IIH often mimic those of a brain tumor. Therefore, the disease is often called pseudotumor cerebri, or “false brain tumor.”
Are you at risk for IIH?
Surprisingly, IIH is most common in women between the ages of 20 and 50; more than 90% of those affected are women.
Remember, high body weight or obesity, defined as a body mass index (BMI) greater than 30, is a major risk factor. Your risk also increases if you’ve recently gained a lot of weight.
How is Idiopathic intracranial hypertension diagnosed?
Usually, your neurologist will take a thorough medical history and perform a physical exam.
Thereafter, your eye doctor will look for signs of increased intracranial pressure on the eye. These include:
- Papilledema
- Visual loss
- Possible weakness in the lateral rectus muscles, which may lead to a squint, and possible double vision.
What are the tests for Idiopathic intracranial hypertension?
The eye tests performed are:
- Comprehensive dilated eye exam
- Visual field testing or perimetry
- Occasionally, RNFL OCT to image the optic nerve and its thickness
- Optic nerve photo
Other tests include:
- Brain imaging, including computed tomography (CT) and magnetic resonance imaging (MRI) scans
- Lumbar puncture, or spinal tap, to measure CSF pressure, and to test it for infection.
in fact, all these tests. may be required for diagnosis, and have to be repeated at regular intervals to monitor the clinical course of the disease.
How is idiopathic intracranial hypertension treated?
Acetazolamide is the most commonly used drug that decreases CSF production. Therefore, it decreases the intracranial pressure.
In addition, weight loss through healthy eating, restriction of salt intake, and exercise is key to the treatment of IIH.
Rarely, surgery may be required to relieve pressure on the optic nerve.
