Pseudotumor cerebri (PTC) is caused by high pressure in the fluid around the brain. The condition can mimic the symptoms of a brain tumor. The condition is sometimes referred to as Idiopathic intracranial hypertension (IIH).
Anatomy of the brain
Inside the brain are four ventricles. CSF flows through the ventricles by way of channels that connect one ventricle to another. Eventually, the CSF is absorbed into the bloodstream. In order to maintain normal pressure inside the skull the production, flow and absorption of CSF must be kept in balance.
In patients suffering from PTC or IIH, the pressure inside the brain builds and causes severe, chronic headaches, vision problems and ringing in the ears. Most patients are first evaluated for a brain tumor before their neurologist suspects PTC or IIH. It is unknown why this condition occurs. It is mostly identified in young women who are overweight.
Patients with PTC or IIH may present with any of the following symptoms:
- Chronic, severe headaches
- Ringing in the ears
- Blurred vision
- Tunnel vision
- Loss of vision
- Double vision
- Papilledema (swelling of the optic disc)
There are patients who are at greater risk for developing the condition. These risk factors include being:
- Young adulthood Ages 18-35
- Overweight or obese
An evaluation will include the following:
- Clinical exam
- Imaging studies. Imaging studies are highly unreliable in the diagnosis of PTC or IIH because the size of the ventricles does not change. However, the doctor may recommend this test to rule out other possible neurological conditions.
- Examination of your visual fields by a highly trained neuro-ophthalmologist. These exams will include:
- Assessing the patient's peripheral vision
- Using a color chart to determine if the patient can distinguish different colors
- Using an eye chart to ascertain central vision acuity
- Dilation of the pupils in order to examine the optic discs for swelling
If the neurologist or neuro-ophthalmologist suspects you have PTC or IIH, he or she will recommend a very aggressive evaluation and treatment plan. If IIH is not treated immediately, permanent and lasting damage can occur to a patient's vision. If the doctor continues to suspect a diagnosis of PTC or IIH, he or she will probably order a spinal tap. This spinal tap will measure the pressure of CSF using a manometer, a measurement tool. If the pressure is determined to be too high, the doctor may recommend:
- Weight loss
- Weight loss and medication taken by mouth
- Placement of a permanent shunt in order to maintain the correct balance of CSF
- Making an opening in the covering of the optic nerve to let the fluid out and relieve pressure on the nerve.
In most cases, the condition can be treated successfully with a combination of weight loss and intracranial pressure-lowering medication. It is almost always present in young women who are overweight. Research has shown that if an individual loses up to 10% of her body weight, her intracranial pressure will become normal and symptoms and signs of IIH will resolve. However, this is not always a long-term solution, so medication and/or surgery might be recommended.
If medication and weight loss do not resolve the symptoms from IIH, the doctor will probably recommend either placement of a shunt to drain the excess CSF away from the brain or a surgical procedure in which an opening is made in the covering of the optic nerve to release the fluid and relieve pressure on the nerve.
Surgical treatment method
Most patients with the condition are good candidates for two types of shunts:
- Ventricular shunt- the fluid will be drained from the brain into the peritoneal cavity, stomach or into a chamber in the heart
- Lumbar shunts- the fluid will be drained from the spinal region into the peritoneal cavity or stomach
- Optic nerve sheath fenestration- an opening will be made in the covering of the optic nerve to release fluid and relieve pressure on the nerve.
The goal of the shunt is to remove the correct amount of CSF so the patient has relief from all IIH symptoms. The most critical part of the treatment for PTC or IIH is to insure that the shunt relieves the pressure in the brain so that the eyes are protected. Because the amount of CSF is usually as small as 1 cc, a special valve is used. Your doctor may recommend a procedure called an optic nerve sheath fenestration. The goal of this procedure is to relieve the pressure on the nerve by making an opening in the covering of the nerve so that the CSF can escape.