Idiopathic Intracranial Hypertension
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.”
An outdated name for idiopathic intracranial pressure is pseudotumor cerebri. Pseudotumor cerebri means false brain tumor. IIH used to sometimes be called pseudotumor cerebri because the symptoms can be similar to brain tumor symptoms.
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).
- 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).
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:
- 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.
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.
Outlook / Prognosis
What is the outlook for people with intracranial hypertension?
Without treatment, intracranial hypertension may lead to permanent vision loss. But most people find that treatment relieves intracranial hypertension symptoms. After treatment, you'll need regular checkups with an ophthalmologist (eye doctor) to monitor your vision.
What conditions cause similar symptoms to IIH?
Some conditions that affect your brain and spine may have similar symptoms to intracranial hypertension. These conditions include:
- Arachnoiditis: Swelling and inflammation in the membrane around your spinal cord.
- Brain tumors: Masses of irregular cells in your brain.
- Epiduritis: Inflammation in the outer tissues of your brain and spinal cord.
- Meningitis: Infection of the membranes (meninges) surrounding your brain and spinal cord.
What else should I ask my doctor?
You may also want to ask your healthcare provider:
- What's the most likely cause of intracranial hypertension symptoms?
- What tests do I need to diagnose intracranial hypertension?
- Can I do anything at home to manage symptoms?
- Can anything worsen IIH symptoms and signs?
- Do I need to lose weight to reduce symptoms?
- How can I best manage IIH along with other health conditions?
A note from Cleveland Clinic
Intracranial hypertension is increased pressure in your skull. It occurs because of CSF buildup. If you have idiopathic intracranial hypertension, it means healthcare providers don’t know what’s causing the fluid buildup. Intracranial hypertension can put pressure on your optic nerve. Symptoms often include severe headaches, blurred vision, blind spots or vision loss. If you have IIH, treatment might include weight loss, medications or surgery.
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