What is idiopathic intracranial hypertension? Idiopathic intracranial hypertension (IIH) is increased pressure around your brain. It occurs when cerebrospinal fluid (CSF), the liquid that cushions your spinal cord and brain, builds up in your skull. Pressure builds up in your brain and on your optic nerve, the nerve at the back of your eye that helps you see. The word idiopathic means “no known cause.” Intracranial means “in the skull,” and hypertension means “high pressure.” Who might get idiopathic intracranial hypertension? Women are more likely to develop IIH than men. About 19 in 20 people with idiopathic intracranial hypertension are women. Most are between ages 20 and 50. You are also more likely to have IIH if you have:

• Body mass index (BMI) above 30.
• Chronic kidney disease.
• Conditions that affect your hormones, such as Cushing’s syndrome, hypothyroidism or hyperthyroidism.
• Iron deficiency anemia (lack of red blood cells).
• Lupus.
• Polycythemia vera (too many red blood cells).
• How common is idiopathic intracranial hypertension?
• Overall, about 1 in every 100,000 people have idiopathic intracranial hypertension. In young females who have obesity, the rate is about 20 out of every 100,000.

SYMPTOMS AND CAUSES What causes intracranial hypertension? Some intracranial hypertension occurs because of known causes. Some people have chronic (long-lasting) intracranial hypertension because of health conditions like brain tumors or blood clots. Acute (sudden) intracranial hypertension can occur after a:

• Brain abscess (collection of pus and swelling in the brain).
• Head injury or traumatic brain injury (TBI).
• Stroke.
• If you have idiopathic intracranial hypertension, that means CSF builds up for no known reason. This type can affect anyone but is most common in younger women who carry excess weight.

What are the symptoms of intracranial hypertension? The most common sign of intracranial hypertension is a sudden, severe headache. Sometimes the headache is so painful that it wakes you from sleep. People with IIH may also have a change in vision. You might see double or have sudden blind spots. Several conditions can cause these symptoms, so check with your provider to find out if symptoms are related to IIH or another condition. Intracranial hypertension symptoms can also include:

• Fatigue.
• Headaches.
• Loss of peripheral (side) vision.
• Nausea and vomiting.
• Shoulder and neck pain.
• Temporary blindness.
• Tinnitus (ringing in your ears)

DIAGNOSIS AND TESTS How is intracranial hypertension diagnosed? IIH used to be known as pseudotumor cerebri because the symptoms resembled symptoms of a brain tumor. Your provider may use several diagnostic tests to rule out a tumor and find the cause of your symptoms. You may have:

• Brain CT scan or MRI.
• Eye exam to check for swelling near your optic nerve.
• Spinal tap (lumbar puncture) to evaluate your CSF.
• Tests to check your reflexes, balance or muscle strength.
• Visual field test to check for blind spots in your vision.

MANAGEMENT AND TREATMENT How is idiopathic intracranial hypertension treated? For most people, intracranial hypertension symptoms improve with treatment. Your provider may recommend:

• Weight loss: If you have a high BMI, weight loss can reduce IIH symptoms. Your healthcare provider may recommend losing 5% to 10% of your body weight.
• Medication: Some medicines manage IIH symptoms. Your provider may prescribe acetazolamide (Diamox®) or topiramate to help your body produce less CSF. You may also take a diuretic (water pill) to decrease fluid retention.
• Surgery: In severe cases, you may need surgery for IIH. Your provider may recommend a spinal fluid shunt. A shunt is a long, thin tube placed in your brain to drain excess CSF. Or you may have an eye surgery called optic nerve sheath fenestration. Your provider makes small incisions around your optic nerve to allow better CSF drainage.

PREVENTION How can I reduce my risk of intracranial hypertension? If you have a condition that increases your risk of IIH, speak with your provider about how to best manage it. For example, if you have a high BMI, you can reduce your risk of IIH by losing weight. If you have iron-deficiency anemia, you may take iron supplements or other medications. Can you live a normal life with intracranial hypertension? In some people, after diagnosis, IIH can settle itself. For the majority weight loss and combined with medical treatment, will control the symptoms well. However, some people may continue to have disabling symptoms despite treatment. What is the life expectancy of someone with IIH? IIH does not normally affect life expectancy. The major complications from IIH arise from untreated or treatment-resistant papilledema. In various case series, the long-term risk of one's vision being significantly affected by IIH is reported to lie anywhere between 10 and 25%.