Pseudotumor cerebri is a condition that causes increased pressure inside the skull, resulting in symptoms similar to those of a brain tumor, particularly visual disturbances. It is caused by a buildup of cerebrospinal fluid within the brain and, untreated can lead to vision loss.
Certain medications or underlying medical conditions may cause increased intracranial pressure, resulting in pseudotumor cerebri. When no underlying cause can be determined, the condition is referred to as idiopathic intracranial hypertension. While pseudotumor cerebri can be the result of a congenital condition, and can occur in children as well as adults, it is most commonly diagnosed in women of childbearing age.
Causes of Pseudotumor Cerebri
The precise cause of pseudotumor cerebri is unknown, but it appears that patients with this disorder have a problem reabsorbing the cerebrospinal fluid that normally cushions the brain and spinal cord, resulting in excessive intracranial pressure. The condition is called "pseudotumor" because a tumor, by crowding the cranial cavity, would have the same effect.
Research indicates that many patients with pseudotumor cerebri have stenosis (narrowing) in the large transverse sinuses in the brain, but in some cases it is unclear whether this is a precursor or result of the condition. Apart from being a woman of childbearing age, risk factors for pseudotumor cerebri include obesity, some medical conditions, such as lupus or sleep apnea, and certain medications.
Symptoms of Pseudotumor Cerebri
Symptoms of a pseudotumor, which frequently mimic those of a brain tumor, may include:
- Headaches, especially behind the eyes
- Nausea and vomiting
- Tinnitus (ringing in the ears)
- Blurred, dimmed or double vision
- Problems with peripheral vision
- Brief episodes of blindness (obsurations)
- Photopsia (seeing light flashes)
- Neck, back or shoulder pain
The reason pseudotumor cerebri may cause so many visual disturbances is that the disorder often results in the swelling of the optic nerve.
Diagnosis of Pseudotumor Cerebri
If pseudotumor cerebri is suspected, eye examinations and visual field tests are usually administered. Other diagnostic tests that may be used to rule out an actual brain tumor and confirm the diagnosis of pseudotumor cerebri include: MRI and CT scans of the brain and a lumbar puncture (spinal tap) to obtain samples of cerebrospinal fluid for laboratory examination.
Treatment of Pseudotumor Cerebri
The focus of treatment is to improve symptoms and preserve the patient's vision. If pseudotumor cerebri is caused by obesity, weight loss may be recommended. Symptoms may also be treated with diuretics or medications for migraines or glaucoma. In severe cases, one of two types of surgery may be considered.
One type of surgical procedure is an optic nerve sheath fenestration during which a window is cut in the membrane surrounding the optic nerve to allow excess cerebrospinal fluid to be drained. The other operation involves the insertion of a spinal fluid shunt which allows excess fluid to drain from elsewhere in the body.