Idiopathic intracranial hypertension (pseudotumor cerebri)

Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is a cerebrovascular disorder in which cerebrospinal fluid builds up around your brain without a known reason, increasing the pressure in your skull. Cerebrospinal fluid (CSF) is a clear liquid that nourishes and protects the brain and spinal cord.

Pseudotumor cerebri, which means false brain tumor, is an older but still used term for IIH.

IIH is defined as:

• Idiopathic =“unknown cause”
• Intracranial = “within the skull”
• Hypertension = “high pressure”

Increased pressure in IIH can cause headaches and swelling of the optic nerve (papilledema). The optic nerve carries information between your brain and eye and helps you see.

How common is idiopathic intracranial hypertension?

IIH is a rare condition that affects mainly women and is strongly associated with obesity. Overall, about two new cases occur in every 100,000 people each year. In women between the ages of 15 and 44 who have obesity, the rate is 22 in 100,000.

At Penn Medicine, our specialists have the experience needed to accurately diagnose IIH and preserve your vision.

Headaches are the most common symptom of idiopathic intracranial hypertension. These headaches may become progressively worse and more frequent and can impact your quality of life. 

Other symptoms include: 

• Blurred or darkened vision 
• Dizziness 
• Double vision 
• Neck or back pain 
• Whooshing or thumping in the ears that matches your heart rate (pulsatile tinnitus) 

Rarely, IIH can lead to permanent blindness. 

Intracranial hypertension is the result of a buildup of cerebrospinal fluid. Normally, your brain continuously produces and reabsorbs CSF to maintain a constant volume. In intracranial hypertension, there is a loss of CSF balance due to increased production or decreased absorption of CSF. 

Often, intracranial hypertension has a known cause. For example, acute (sudden) intracranial hypertension can occur because of a stroke or blow to the head. Intracranial hypertension can also develop over time due to conditions such as a brain tumor or medications. 

But in pseudotumor cerebri, the cause of the high pressure in your skull is usually not known. In some cases, IIH may be related to narrowing of the large veins that drain blood from the brain (venous sinus stenosis). 

IIH is rarely curable, but weight loss, medications and surgery can significantly reduce symptoms and preserve vision. For people with venous stenosis and IIH, venous stenting is a very effective treatment. 

Pseudotumor cerebri treatment at Penn Medicine 

IIH is usually associated with obesity, so weight loss is a primary treatment. Your doctor may recommend losing five to 15 percent of your weight to reverse the symptoms of IIH. 

Medications are also a treatment option to help: 

• Decrease the production of CSF 
• Reduce overall fluid retention in your body 
• Relieve headaches 

If other treatments are not effective or if your vision is in danger, your doctor may recommend surgery to improve CSF drainage. Surgical procedures to treat pseudotumor cerebri include: 

• CSF diversion surgery: The surgeon places a long thin tube (shunt) between your brain and abdomen to drain CSF. 
• Venous stenting: In this relatively new technique, the surgeon inserts a thin tube (catheter) into a blood vessel and advances it to the venous sinuses in the brain. They thread a metal mesh hollow tube called a stent through the catheter and open it to fit inside the vein. The stent eliminates the outflow obstruction in the venous sinuses. 

Idiopathic intracranial hypertension and pregnancy 

Women of childbearing are most often affected by IIH. If you have IIH and are pregnant or planning a pregnancy, talk to your doctor about: 

• Medications you can safely use during pregnancy 
• Safe levels of weight gain during each trimester 
• Special considerations for delivery