Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension is a rare condition where pressure builds up around the brain without a known cause. While it’s not life-threatening, it can lead to permanent vision loss if left untreated, making early diagnosis and treatment essential.

Table of contents

• What Is Idiopathic Intracranial Hypertension?
• Alternative Names for the Condition
• How Common Is the Condition?
• Symptoms
• What Causes the Condition?
• Risk Factors
• How Is It Diagnosed?
• Treatment Options
• Potential Complications
• Long-Term Outlook

What Is Idiopathic Intracranial Hypertension?

Idiopathic intracranial hypertension (IIH) is a condition where pressure builds up around your brain without a clear medical explanation^[1]. This happens when cerebrospinal fluid (CSF)—the liquid that normally cushions your brain and spinal cord—builds up inside your skull^[1]. The increased pressure affects your optic nerve, which is the nerve at the back of your eye that helps you see^[1].

The name tells us something about the condition itself. “Idiopathic” means the cause is unknown. “Intracranial” means inside the skull. “Hypertension” means high pressure^[1]. Healthcare providers don’t fully understand why the cerebrospinal fluid builds up, though researchers think there may be a blockage in the path the fluid uses to travel through your brain or a narrowing of the large veins in your brain^[1].

Alternative Names for the Condition

pseudotumor cerebri, benign intracranial hypertension

Idiopathic intracranial hypertension used to be called pseudotumor cerebri, which means “false brain tumor”^[1]. Doctors used this name because the symptoms can be very similar to those caused by a brain tumor^[1]. The condition has also been called benign intracranial hypertension^[6]. However, the term “idiopathic intracranial hypertension” is now the preferred and more precise name^[6].

How Common Is the Condition?

Idiopathic intracranial hypertension is a rare condition. It affects an estimated 0.2 to 2 people out of 100,000 in the general population^[1]. However, the rate is much higher in certain groups. In young women who are overweight, the condition can affect about 20 out of 100,000 people—which is 20 times higher than in people with normal weight^[9].

Most people who develop IIH are women between the ages of 20 and 50^[2]. In fact, about 19 out of 20 people with IIH are women^[2]. The condition most commonly affects women between ages 20 and 45, particularly those with a body mass index (BMI) above 30^[1]. Because of the close relationship between obesity and IIH, and since obesity rates have increased dramatically in recent years, the number of people developing IIH is expected to rise rapidly^[9].

Symptoms

Symptoms of idiopathic intracranial hypertension develop when pressure increases around your brain. The most common and significant signs include^[1]:

• Headaches that are sudden and severe
• Double vision
• Loss of peripheral (side) vision
• Temporary blindness or blind spots in vision
• Ringing in your ears (tinnitus)
• Nausea and vomiting
• Shoulder and neck pain
• Fatigue

Headaches are the most common symptom, affecting about 84% of people with IIH^[6]. These headaches can be throbbing and may be worse in the morning or when coughing or straining^[4]. They may improve when standing up^[4]. About 68% of people experience temporary visual obscurations—a “graying out” of vision lasting seconds at a time, often triggered by coughing, sneezing, or bending down^[6].

Some people experience pulsatile tinnitus, which means hearing a pulsing or rhythmic noise in the ears that matches their heartbeat^[1]. This affects about 52% of people with IIH^[6]. About 18% of people may experience double vision, which happens because of pressure affecting the nerve that controls eye movement^[6].

Less commonly, people may experience problems with coordination and balance, mental confusion, feeling sleepy or irritable, and difficulty looking at bright lights^[4]. Some people may also experience memory problems, difficulty finding the right words, or nerve pain^[15].

Because several conditions can cause these symptoms, it’s important to check with a healthcare provider to find out if they are related to IIH or something else^[1]. If you notice changes in your vision along with headaches or ringing in your ears, let a healthcare provider know immediately^[1].

What Causes the Condition?

Healthcare providers don’t know the exact cause of idiopathic intracranial hypertension^[1]. The word “idiopathic” specifically means that the cause is unknown^[1]. This is what makes it different from other types of intracranial hypertension that have known causes, such as a severe head injury, stroke, brain tumor, or infection^[4].

Researchers have some theories about what might be happening. One possibility is that there may be a blockage in the pathway that cerebrospinal fluid uses to travel through the brain^[1]. Another theory is that the large veins in the brain may become narrowed, causing fluid or blood to back up as it tries to exit the brain, which increases pressure^[1].

While the exact cause remains unknown, some factors seem to be linked to the development of IIH. These include certain hormone conditions like hypoparathyroidism or Addison’s disease, some medications (including certain antibiotics, lithium, and thyroid medications), high levels of vitamin A, iron deficiency anemia, and conditions affecting the immune system like lupus^[4].

Risk Factors

While idiopathic intracranial hypertension can affect anyone, certain factors increase the likelihood of developing the condition^[1]:

• Being female
• Being between ages 20 and 45
• Having a body mass index (BMI) above 30
• Recent weight gain

Obesity is one of the strongest risk factors for IIH^[2]. Being overweight or obese makes IIH more likely, and people who have recently gained weight are at higher risk^[2]. The condition occurs much more frequently in young women who are overweight, with rates about 20 times higher than in people with normal weight^[9].

Some medications have been linked to a higher risk of developing IIH. These include birth control pills, certain antibiotics, chemotherapy medicines, steroids, and some acne medicines^[3]. Other medicines that can increase risk include amiodarone, growth hormone, isotretinoin (Accutane), lithium carbonate, tetracycline, and drugs containing vitamin A^[5].

Certain medical conditions are also linked to IIH, including thyroid conditions, chronic kidney failure, Down syndrome, polycystic ovary syndrome, obstructive sleep apnea, and some infectious diseases^[5].

Studies are ongoing to learn whether IIH can run in biological families^[1]. Some people who have the condition report that family members have had it too^[1].

How Is It Diagnosed?

To diagnose idiopathic intracranial hypertension, a healthcare provider will review your symptoms and medical history, perform a physical exam, and order several diagnostic tests^[1]. The goal is to rule out other conditions that can cause similar symptoms, particularly brain tumors^[3].

An eye doctor (ophthalmologist) will perform a detailed examination of your eyes^[1]. This includes looking for swelling of the optic nerve at the back of the eye, a condition called papilledema^[6]. The eye exam will also include a visual field test to check for blind spots in your vision^[1]. You may have photos taken of your eyes and an imaging test to measure the thickness of the layers of your retina^[10].

Brain imaging is essential and is usually done before any other invasive procedures. Your doctor will likely order a magnetic resonance imaging (MRI) scan or computed tomography (CT) scan of your brain^[1]. These tests help rule out other problems that can cause similar symptoms, such as brain tumors and blood clots^[10]. An MRI with magnetic resonance venography (MRV) is preferred because it can also check for blood clots in the brain’s veins^[6].

Once a brain scan rules out other causes, a lumbar puncture (also called a spinal tap) is performed^[1]. During this procedure, a specialist inserts a needle between two vertebrae in your lower back and removes a small amount of cerebrospinal fluid for testing^[10]. This test measures the pressure inside your skull and analyzes the spinal fluid^[1]. A lumbar puncture should never be performed before neuroimaging^[6].

Your doctor may also perform an examination to check functions such as your muscle strength, reflexes, and balance, as any problems could be a sign of an issue with your brain or nerves^[4].

Idiopathic IIH is diagnosed when you have increased pressure in the fluid surrounding your brain and no other cause can be found^[4].

Treatment Options

The goal of treatment for idiopathic intracranial hypertension is to preserve vision and reduce symptoms, particularly headaches^[8]. Treatment is tailored based on symptoms and the extent of visual impairment^[8].

Weight Loss

For people who are overweight or obese, weight loss is usually the first treatment recommended^[2]. Losing just 5 to 10 percent of your body weight can help lessen symptoms^[2]. For example, if you weigh 200 pounds, losing 10 to 20 pounds may be enough to see improvement^[2]. Weight loss is important because it can reverse the underlying cause of the condition^[11]. Your doctor may recommend consultation with a nutritionist or involvement in an intensive weight-loss program^[11].

Medications

The first-line medical treatment is typically a medicine called acetazolamide (Diamox)^[2]. This medication helps your body make less cerebrospinal fluid, which reduces pressure around the brain^[11]. The starting dose is usually 500 mg twice daily, but it can be increased up to 3-4 grams daily depending on the severity of symptoms and response to treatment^[11]. In a recent clinical trial, acetazolamide combined with weight loss was found to be more effective than weight loss alone in patients with IIH and mild visual loss^[11].

Another medication option is topiramate, which works similarly to acetazolamide by reducing cerebrospinal fluid production^[11]. Topiramate has the added benefit of promoting weight loss and can be effective for treating migraine headaches, which often occur alongside IIH^[11].

If you can’t tolerate acetazolamide or topiramate, your doctor may try furosemide, a type of water pill (diuretic) that helps the body get rid of extra fluid^[3]. However, furosemide has less effect on cerebrospinal fluid production than the other medications^[11].

A short course of steroid medicine may be used to relieve headaches and reduce the risk of vision loss^[4].

For patients with migraine or tension-type headaches occurring alongside IIH, treatment by a headache specialist may be beneficial^[11]. It’s important to note that acetazolamide is less effective for treating the headaches associated with IIH compared to its effect on vision problems^[11].

Lumbar Puncture

A lumbar puncture (spinal tap) can help relieve pressure in the brain and prevent vision problems^[5]. Repeat lumbar punctures are particularly helpful for pregnant women to delay surgery until after delivery^[5]. However, the use of repeated lumbar punctures remains controversial^[8].

Surgery

Surgery may be considered if other treatments don’t help, particularly if your vision is getting worse or you’re at risk of losing your vision^[4]. If there is an immediate threat to visual function, a temporary cerebrospinal fluid draining procedure may be performed immediately while a definitive surgical plan is made^[8].

The main types of surgery for IIH include^[4]:

• Shunt surgery: A thin, flexible tube is inserted into the fluid-filled space in your skull or spine to divert excess fluid to another part of your body, such as your abdomen. This can be either a ventriculoperitoneal shunt or a lumboperitoneal shunt^[8].
• Optic nerve sheath fenestration: The protective layer surrounding your optic nerve is opened up to relieve pressure on it and allow fluid to drain away^[4].

A newer surgical option is venous sinus stenting, an endovascular treatment for patients whose condition doesn’t respond to medical therapy^[8]. This procedure involves placing a stent to open narrowed veins in the brain. While preliminary studies suggest it may be effective in select patients with appropriate venous anatomy, it has not yet been studied in a randomized controlled clinical trial^[11].

All surgical procedures carry risks of potentially serious complications, so it’s important to talk to your surgeon about what the operation involves and what the risks are^[4].

Bariatric Surgery

For patients who are unable to lose weight through traditional methods, bariatric surgery (weight-loss surgery) may be an effective option^[8]. This may be supported by medications like GLP-1 receptor agonists that help with weight loss^[8].

Additional Considerations

Your doctor may recommend limiting fluids or salt in your diet^[3]. If you’re taking any medicines that may be causing your symptoms, your doctor may recommend stopping them^[4].

Regular eye examinations, especially visual field tests, are essential to evaluate the effectiveness of treatment^[8]. These tests are crucial because simple visual acuity exams may not detect early signs of vision loss^[8]. If vision deteriorates despite ongoing treatment, surgery may be needed urgently^[8].

Potential Complications

The most serious complication of idiopathic intracranial hypertension is permanent vision loss^[1]. This happens because the increased pressure around the brain causes swelling of the optic nerve^[4]. If left untreated, chronic swelling of the optic nerve (papilledema) may lead to progressive optic atrophy, visual field loss, and ultimately blindness^[6].

At the time of diagnosis, various degrees of visual impairment are present in up to 90% of patients with IIH^[9]. In earlier studies, an estimated 10 to 24 percent of people with IIH progressed to severe and permanent visual impairment^[9]. However, more recent studies show that the visual prognosis can be good with earlier diagnosis, increased awareness, dedicated team effort, and close follow-up^[9].

Vision loss from IIH can occur at any time during the disease but is often gradual and may go unnoticed by patients because central vision is usually preserved until late in the illness^[9]. This is why it’s so important to inform your healthcare provider as soon as you notice any changes to your vision^[1]. Once vision loss occurs, it is irreversible^[1], but a healthcare provider can offer treatment options to prevent this complication^[1].

With early and accurate treatment, vision can often be preserved^[17]. This is why it’s so important for patients to be seen and treated in a timely manner^[17].

Long-Term Outlook

Idiopathic intracranial hypertension is not usually life-threatening^[4]. However, it can be a lifelong problem that significantly affects quality of life^[4].

For some people, IIH can settle on its own after diagnosis^[15]. In some cases, the condition disappears on its own within six months^[5]. For the majority of people, weight loss combined with medical treatment will control symptoms well^[15]. Once patients reach their weight loss target (typically 6 to 10 percent of body weight), they can often be tapered off acetazolamide^[11].

However, some people may continue to have disabling symptoms despite treatment^[15]. In some cases, the pressure inside the brain remains high for many years^[5]. Symptoms can return in some people^[5]. A small number of people have symptoms that slowly get worse and lead to blindness^[5].

Most people with IIH will need to have their vision closely monitored over time^[5]. Follow-up MRI or CT scans may be done to rule out other problems such as tumors or hydrocephalus (buildup of fluid inside the skull)^[5].

With treatment, most people with IIH can manage their symptoms and preserve their vision^[1]. The key is early diagnosis and appropriate treatment to prevent the irreversible complication of vision loss^[1].