Most authorities eschew the use of corticosteroids and have objected strenuously to their inclusion as a treatment for pseudotumor in previous editions of this book. Nevertheless, with the administration of prednisone (40 to 60 mg/d) we have occasionally observed a gradual recession of papilledema and a lowering of CSF pressure, but such responses were not consistent or sustained and it has been difficult to decide whether this represented the effect of treatment or the natural course of the disease. Greer, who reported on 110 patients, 11 of whom were treated with these agents, decided that they were of no value. Moreover, in patients whose papilledema seems to recede under the influence of corticosteroids, there is always a danger that it will recur when the drug is tapered. Considering the potential for undesirable side effects of corticosteroids, we have used them very sparingly and only for brief periods while preparing the patient for more definitive treatment.
Fenestration of the Optic Nerve Sheath
For patients who are losing vision, unilateral fenestration of the optic nerve sheath is a procedure favored by some ophthalmologists. According to Corbett and colleagues, this procedure—which consists of partial unroofing of the orbit and the creation of an intraorbital window opening in the dural–arachnoid sheaths surrounding the optic nerve—effectively preserved or restored vision in 80 to 90 percent of patients. Even when the procedure is performed on only one side, its effect on vision is often bilateral and about two-thirds of patients have some relief of headache as well, although this has been transient in most of our patients.
However, the operation carries a moderately high risk of orbital vascular obstruction and unilateral visual loss, as happened in two of our patients. The causes of visual loss after this operation by various reports have included central retinal artery or vein occlusion, choroidal infarction, optic nerve trauma, hemorrhage into the nerve sheath, and infection. Over the past decades, enthusiasm for the procedure had diminished after publication of several series in which there was visual loss in 2 to 11 percent of patients. Some of these data come from studies of sheath fenestration for ischemic optic neuropathy, a condition not comparable to the disc swelling of pseudotumor. Follow-up studies have indicated that the reduction in ICP was limited to 1 year or less. As a result of recent reexamination of the complications of this procedure, considered to be lower than in the past, there is renewed interest for the procedure over lumbar peritoneal shunting.
Relief of Venous Obstruction
In a number of patients, the CSF pressure remains elevated and the papilledema becomes chronic despite one of the above-described treatments. It is the management of this group that is the most difficult and controversial. A careful search should then be made for anatomic and hematologic causes that might underlie cerebral venous dural sinus disease. Sometimes it is useful to treat venous occlusion using interventional vascular techniques. In cases of venous thrombosis antiphospholipid antibody syndrome, sickle cell disease, hormonally induced clotting, and related disorders, medical measures may be tried first, but intravascular thrombolysis remains an option.
The more complex decision to apply stenting to the partial occlusion of the transverse sinus by generous pacchionian granulations should probably be guided by the same principles, that is, failure of medical treatment to adequately control CSF pressure, or relive the threat to vision. In a series of 10 patients with intractably raised CSF pressure and morphologic obstruction in the venous sinuses, Donnet and colleagues were able to provide complete relief by stenting in 6 patients and partial relief in 2 patients, with follow-up ranging from 6 to 36 months. In a summary of published cases and series of patients with pseudotumor cerebri treated by endovascular stenting of venous sinus stenosis, Arac and colleagues concluded that approximately 80 percent were relieved of their main symptoms, and a similar proportion showed resolution, or improvement in papilledema. This is a selected group of patients.