Benign Intracranial Hypertension (Pseudotumor Cerebri)

Pseudotumor cerebri is a rare condition that is most commonly seen in overweight females. The incidence in the general population is low (-0.9/100,000); however, in obese females weighing more than 20% of ideal body weight, the incidence rises to -20/100,000. Associations with vitamin A, tetracycline, estrogen, and steroid use, steroid tapering, and various endocrine problems have been reported. Except for vitamin A use, these associations are based mostly on case reports and may not be universally applicable; their absence should by no means dissuade one from making the diagnosis. An imaging study followed by a lumbar puncture are required to establish diagnosis. The criteria for diagnosis include the following:

• Elevated ICP (>20 cm H20)
• Normal neurologic examination except papilledema (and sixth nerve palsy)
• Normal neuroimaging (no mass or ventricular enlargement)
• Normal CSF (except low CSF protein)
• No suspicion of cerebral venous sinus thrombosis or other cause for elevated ICP

Causes

• Most cases of pseudotumor cerebri occur in young women who are obese and, less frequently, in men who are otherwise healthy.

• If this disorder presents in an individual who is not overweight, ruling out associated risk factors is necessary. These risk factors include systemic diseases (including Lyme disease), disruption of cerebral venous flow, certain endocrine or metabolic disorders, and exposure to or withdrawal from certain exogenous substances.

Symptoms

• Headache ++++ can be constant or intermittent, often retrobulbar +++, and sometimes worse with eye movement
• Transient visual obscurations +++ defined as visual symptoms lasting seconds to minutes
• Nausea +++
• Visual loss ++
• Neck pain ++
• Vomiting ++
• Diplopia ++
• Tinnitus ++0
• Radicular back and neck pain ++
• Diminished sense of smell ++

Signs

• Papilledema - very frequent, but precise figures are unavailable, since the diagnosis may be made less often in its absence.
• Sixth nerve palsy may occur by definition. To make the diagnosis, no other neurologic physical findings are allowed.

Treatment

Few treatable diseases can cause raised intracranial pressure and symptoms of pseudotumor cerebri. A thorough physical examination is needed to rule out these disorders. If a diagnosis of pseudotumor cerebri is confirmed, hyperosmotic drugs may be used to reduce fluid buildup. Diuretics are commonly used to relieve pressure. Weight loss and cessation of certain drugs (including oral contraceptives) will lead to improvement. Therapeutic shunting, which involves surgically inserting a draining tube from the spinal fluid space in the lower spine into the abdominal cavity, may be needed to remove excess fluid and relieve pressure. Close, repeated ophthalmologic exams are required to monitor any changes in vision. Surgery may be needed to remove pressure on the optic nerve.