Pseudotumor cerebri is an eye condition that can be confused with a brain tumor due to swelling of the optic nerve. Like a brain tumor, the fluid inside the skull that cushions the brain and flows around the spinal column develops elevated pressure. It is also referred to as Idiopathic Intracranial Hypertension or Benign Intracranial Hypertension. It is more prevalent in women between the ages of 20 and 50. Symptoms of pseudotumor cerebri are usually an undiagnosed chronic headache, and in more severe cases there may be visual symptoms such as double vision. Also nausea and vomiting may occur. There is an unusual effect of pulsating sounds within the head that are synchronous with the heart rate referred to as Pulse-synchronous tinnitus.
A routine eye exam is where the initial diagnosis of mild cases of pseudotumor cerebri is often first made. The optic nerve that enters the back of the eye appears elevated in both eyes, a condition referred to as papilledema. Because the nerve is an extension of the brain and enclosed by the same tissues and fluid that cushion the brain, elevation in the pressure inside the brain also cause the nerve to swell. Since most cases occur in young to middle age overweight females, an elevated nerve with a history of chronic headaches and otherwise healthy is often indicative of pseudotumour cerebri. Other visual symptoms include double vision, brief periods of blurred vision or dim vision, and occasionally patient will have temporary episodes of blindness in one or both eyes. Changes in posture such as suddenly standing up or bending over may elicit symptoms, as may coughing or sneezing.
Double vision may occur when looking to the side. This is caused by a defect in abduction or the ability of an eye to turn out. due to a restriction in the capacity for one or both eyes to turn out. This presents a confusing picture when taken out of context because it is not due to damage to the abducens nerve (6th Cranial Nerve) that controls the eyes outward motion. In this case, the double vision is called a false localizing sign. Pain can occasionally be associated with eye movements.
Rarely, the pressure can become very high and cause severe problems with vision and alterations in levels of awareness. Most of the time truly is benign idiopathic intracranial hypertension and is managed by weight loss and occasionally medications. Sometimes discontinuation of certain medication may resolve the problems. The most severe cases may require a shunt to drain the increased fluid from the ventricles in the brain into the abdominal cavity.