Pseudotumor Cerebri – Causes, Signs and symptoms

Pseudotumor Cerebri

Also called: Primary Intracranial Hypertension, Idiopathic Intracranial Hypertension, Benign Intracranial Hypertension

Summary

Pseudotumor cerebri is a rare but potentially serious neurological disorder in which pressure inside the skull (intracranial pressure) increases with no identifiable cause. It causes symptoms that mimic those of a brain tumor (e.g., headaches, dizziness, vision loss), although no tumor can be found.

Pseudotumor cerebri, also known as primary intracranial hypertension, is one type of intracranial hypertension. The other type is secondary intracranial hypertension, in which the condition has a known cause. Possible causes of secondary intracranial hypertension may include brain tumors, hydrocephalus, infection, certain medications, specific disease states (e.g., kidney failure) and excessive vitamin A intake.

Although the cause of pseudotumor cerebri is unknown, certain factors increase the risk of developing the disorder. These include female gender, obesity, and being between the ages of 15 and 50 years. According to the Intracranial Hypertension Research Foundation, among overweight women of childbearing age are 20 times more likely to be diagnosed with pseudotumor cerebri in comparison to the general population.

Diagnosis of pseudotumor cerebri is one of exclusion, in that it requires a physician to eliminate other possible causes of a patient’s symptoms. This is likely to involve physical and neurological examinations, as well as imaging tests, blood tests and a spinal tap.

Once a patient is diagnosed with pseudotumor cerebri, treatment involves methods of reducing intracranial pressure. In many cases, medications are used. When used in conjunction with dietary changes and weight loss, medical therapy is usually successful in treating the problem. In some cases, surgery may be necessary to drain excess cerebrospinal fluid and to relieve intracranial pressure. Surgery may also be necessary to treat problems of vision loss that do not respond to other treatments.

There is no known way to prevent pseudotumor cerebri, although (especially for overweight young women), losing weight may be of help.

About pseudotumor cerebri

Pseudotumor cerebri is a neurological condition in which increased intracranial pressure (pressure within the skull) occurs in the absence of an identifiable cause. Pseudotumor cerebri causes symptoms that mimic those of a brain tumor, although no evidence of a tumor can be found in patients with this disorder. In addition, there are no signs of infection, hydrocephalus (blocked drainage of fluid that surrounds the brain), or any other cause that could explain the increased intracranial pressure.

The condition may also be referred to as primary intracranial hypertension, idiopathic intracranial hypertension or benign intracranial hypertension. Because its cause is unknown, idiopathic (of unknown origin) is sometimes preferred – especially instead of benign (not harmful), which is considered by some to downplay the seriousness of the disorder. However, primary intracranial hypertension appears to be its most current designation.

Pseudotumor cerebri is rare but a potentially serious condition. According to the Intracranial Hypertension Research Foundation, one in 100,000 people in United States develop the condition. They typically experience headaches, dizziness, nausea and vision loss. Most people with pseudotumor cerebri can be effectively treated with no significant consequences. In some cases, however, it can lead to permanent blindness.

Intracranial pressure is related to the amount of material and fluid that can fit within the limited space of the skull. The skull contains a variety of tissues and fluids, including the brain, nerves, blood vessels and cerebrospinal fluid (CSF). An increase in pressure within the skull can squeeze the brain, nerves or blood vessels, causing symptoms of pseudotumor cerebri. The cause of the pressure increase is not known. It is assumed to involve a swelling of tissue and/or increase in fluid within the skull.

Another type of intracranial hypertension is secondary intracranial hypertension. Secondary intracranial hypertension has a known cause, most commonly hydrocephalus, intracranial bleeding, brain tumor, infection, certain medications and systemic diseases (e.g., lupus, leukemia, kidney failure) and excessive vitamin A intake. In diagnosing primary intracranial hypertension, physicians will attempt to rule out these causes of secondary intracranial hypertension.

Risk factors and causes of pseudotumor cerebri

Pseudotumor cerebri is the result of increased pressure within the skull (intracranial pressure). The cause of the increased pressure is unknown.

Physicians have found that patients with pseudotumor cerebri often have a buildup of cerebrospinal fluid (CSF) within the skull. It has been suggested that this may occur due to excessive production of CSF or impaired absorption by the meninges (membranes covering the brain). However, why either of these might occur is unknown.

Physicians have also found that blood flow from the brain is slowed in patients with pseudotumor cerebri. It is suspected that reduced blood flow may cause an increase in blood pressure within the brain and result in intracranial pressure. Another theory is that intracranial pressure results from swelling of the brain due to excess fluid (cerebral edema). However, common causes of cerebral edema (e.g., brain tumor, infection) are not present in patients with pseudotumor cerebri.

While the cause has not been identified, certain factors are associated with higher incidence of pseudotumor cerebri. These include:

  • Female gender
  • Age between 15 and 50
  • Obesity 

These risk factors can greatly increase the chance of developing pseudotumor cerebri. According to the Intracranial Hypertension Research Foundation, the rate of occurrence of pseudotumor cerebri is approximately 20 times higher among overweight women of childbearing age.

Signs and symptoms of pseudotumor cerebri

The signs and symptoms of pseudotumor cerebri result from increased pressure within the skull (intracranial pressure). Headaches, especially behind the eyes, is a common symptom of pseudotumor cerebri. In many cases, the headaches are worse in the morning and become more severe following coughing or straining. Blurred and double vision are also common symptoms of pseudotumor cerebri. This is usually due to swelling around the optic nerve at the back of the eye (papilledema), which may lead to visual loss.

Pseudotumor cerebri may also result in other symptoms, including:

  • Dizziness
  • Nausea and vomiting
  • Pulsating or buzzing noise in the head

In many cases, the symptoms of pseudotumor cerebri are most severe during or following physical activity.

Pseudotumor cerebri is typically a disease of adults, although it can also occur in infants and children. The signs and symptoms that younger patients experience may be different from those of adults. The pressure in the skull may cause a bulging at the back of the head or an increase in head size. In addition, younger patients may not be able to express that they are experiencing headaches and instead may act more irritable as a result of the pain. They can also vomit or become lethargic.

Diagnosis methods for pseudotumor cerebri

Diagnosis of pseudotumor cerebri relies on excluding other possible identifiable causes of a patient’s symptoms, such as brain tumors, hydrocephalus or systemic diseases (e.g., lupus, kidney failure, leukemia).  

Patients with pseudotumor cerebri are likely to see their physician initially with complaints of headaches and/or visual loss. The first step in diagnosis is a review of the patient’s medical history. This will typically involve questions about a patient’s symptoms, including their frequency, severity and possible associated factors. It can include questions about similar symptoms or conditions in family members that might indicate an inherited genetic condition.

A physical examination and neurological examination will be performed. As part of these examinations, a physician will examine the patient’s eyes, ears and reflexes. Vital statistics, including pulse rate, blood pressure and temperature will be taken. If these examinations do not reveal a probable cause of the patient’s symptoms, further tests may be necessary. These are likely to include:

  • Imaging tests. A CAT scan (computed axial tomography) and MRI (magnetic resonance imaging) are used to produce images of the patient’s brain. A negative finding on these brain images excludes a brain tumor may be excluded as a cause of the patient’s symptoms.
  • Spinal tap. Inserting a needle into the space between the vertebrae and the spinal cord allows the physician to sample and analyze the patient’s cerebrospinal fluid (CSF). Elevated CSF pressure is commonly seen in patients with pseudotumor cerebri. A spinal tap can detect the presence of infection (e.g., meningitis).
  • Blood tests. Blood samples may be tested for signs of disease or infection.

In many cases, diagnosis of pseudotumor cerebri will involve evaluation by an ophthalmologist, a physician who specializes in the diagnosis and treatment of eye diseases and disorders. The ophthalmologist can detect signs of swelling around the optic nerve (at the back of the eye) or other possible causes of a patient’s vision loss.

Treatment/prevention of pseudotumor cerebri

Treatment of pseudotumor cerebri focuses on reducing the pressure inside the skull (intracranial pressure). This can be accomplished in multiple ways, including:

  • Medications. Diuretics are a group of medicines used to control fluid content in the body and some types help reduce the production of cerebrospinal fluid (CSF) in the brain. Corticosteroids are sometimes prescribed to reduce inflammation in the brain. Corticosteroids may be unsuitable for patients who require long-term treatment because of the potential for severe side effects.

  • Lifestyle changes. Weight loss and dietary changes (e.g., reducing fluid and salt intake) can be recommended as an aspect of pseudotumor cerebri treatment.

  • Changing medications. Under a physician’s guidance, stopping some types of antibiotics, steroids and/or adjusting other medications may help in the treatment of pseudotumor cerebri.

  • Therapeutic spinal taps. In addition to its use in the diagnosis of pseudotumor cerebri, spinal taps may also be used to reduce fluid pressure within the vertebrae and skull. The procedure may need to be repeated and the duration of relief from symptoms depends on the patient’s rate of production of CSF.

  • Surgical treatment. Surgery can be an option of last resort in treating pseudotumor cerebri. A neurosurgeon may recommend the insertion of a drainage tube to release excess fluids and relieve intracranial pressure. Surgery can be beneficial when other forms of treatment are not effective against vision-related symptoms of pseudotumor cerebri.

Follow-up visits to an ophthalmologist can be recommended for patients with pseudotumor cerebri, particularly in those patients who have forms of visual loss. This can help a physician monitor a patient’s response to treatment and help to ensure a patient’s vision loss does not worsen.

Treatment for pseudotumor cerebri is not always necessary and sometimes it is not completely effective. There are reports of some cases that resolve on their own within six months, especially after a patient loses weight. There are also some patients who experience recurrences despite treatment. These cases tend to be progressive and eventually cause permanent blindness.

Because the cause of pseudotumor cerebri is unknown, it is difficult for physicians to recommend ways to prevent the disease. However, for people who are overweight, especially women of childbearing age, weight loss may reduce the risk of developing the condition.

Questions for your doctor

Preparing questions in advance can help patients to have more meaningful discussions with healthcare professionalsregarding their condition. Patients may wish to ask their doctor the following questions related to pseudotumor cerebri:

  1. Why do you think I have pseudotumor cerebri?
  2. Will my symptoms get worse with time?
  3. What other diseases cause symptoms similar to those of pseudotumor cerebri?
  4. What should I do if my symptoms get worse?
  5. What treatment do you recommend for me? What are the risks or side effects I should be aware of?
  6. Are there certain medications I should avoid?
  7. Will I need surgery?
  8. How necessary is it that I lose weight?
  9. What is the likelihood that my pseudotumor cerebri will recur, even after treatment?
  10. If I have pseudotumor cerebri, can I pass it to my children?
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