Idiopathic Intracranial Hypertension

What is idiopathic intracranial hypertension?

Idiopathic intracranial hypertension (IIH) occurs when elevated pressure surrounding the brain leads to symptoms such as headaches and changes in vision. The term “idiopathic” indicates that the underlying cause is unknown, “intracranial” refers to the area within the skull, and “hypertension” signifies high pressure.

IIH arises when there is an excessive accumulation of cerebrospinal fluid (CSF)—the fluid that surrounds the brain and spinal cord—within the skull. This buildup exerts additional pressure on the brain and the optic nerve, which is the nerve located at the back of the eye.

If you experience any alterations in your vision, it is important to consult your eye care professional. They can determine whether your symptoms are associated with IIH or another medical issue. If it is indeed IIH, there are various treatment options available to alleviate the symptoms.

What are the symptoms of IIH?

Symptoms may include:

  • Headaches

  • Tinnitus (ringing in the ears)

  • Temporary vision loss

  • Double vision

  • Blind spots

  • Pain in the neck and shoulders

  • Loss of peripheral (side) vision

If you observe any changes in your vision or experience other symptoms, it is advisable to reach out to your eye doctor.

Did you know?

  • The symptoms of IIH often resemble those of a brain tumor, which is why IIH is sometimes referred to as pseudotumor cerebri, or “false tumor.”

  • Approximately 19 out of 20 individuals diagnosed with IIH are women.

Am I at risk for IIH?

While IIH is uncommon, certain individuals are at an increased risk. It is most frequently seen in women between the ages of 20 and 50.

Being overweight or obese also heightens the likelihood of developing IIH. You may be at a greater risk if your body mass index (BMI) exceeds 30 or if you have recently experienced weight gain. You can calculate your BMI using the NHS’s online calculator.

What causes IIH?

The exact cause of IIH remains unknown to experts. However, there are other forms of intracranial hypertension that have identifiable causes:

  • Acute intracranial hypertension occurs suddenly, typically due to an accident or stroke.

  • Chronic intracranial hypertension develops gradually, often as a result of a medical condition such as a blood clot or brain tumor, or due to certain medications.

When medical professionals cannot identify a specific reason for the elevated pressure, it is classified as IIH.

How will my doctor check for IIH?

Your eye doctor will conduct several assessments to look for indications of IIH, including a dilated eye examination to inspect the back of your eye and a visual field test to evaluate your peripheral vision.

Additionally, your eye doctor may refer you to a neurologist, a specialist in brain-related conditions. The neurologist will ensure that your symptoms are not due to another health issue, such as a brain tumor. The neurologist may perform tests that include:

  • A physical examination

  • Brain imaging, such as a CT or MRI scan

  • A spinal tap (lumbar puncture) to analyze your CSF

What's the treatment for IIH?

For the majority of individuals, symptoms of IIH improve with appropriate treatment. Treatment options include:

  • Weight loss. For those who are overweight or obese and have IIH, weight loss is typically the initial course of action. Shedding approximately 5 to 10 percent of your body weight can significantly alleviate symptoms—for instance, if you weigh 200 pounds, this would involve losing around 10 to 20 pounds. Discuss with your doctor safe and effective methods for weight loss.

  • Medication. Your physician may prescribe a medication known as acetazolamide (Diamox) in conjunction with weight loss efforts. This medication assists in reducing the production of CSF in your body.

  • Surgery. If other treatment methods prove ineffective, your doctor may recommend surgical options to relieve the pressure. In shunt surgery, a small incision is made, and a thin tube, referred to as a shunt, is inserted to facilitate the drainage of excess fluid from around the brain into the rest of the body. There is also a surgical procedure for the eye where a small opening is created in the membrane surrounding the optic nerve.