CASE OF THE MONTH

CASE #3

Idiopathic intracranial hypertension, commonly known as pseudotumor cerebri, is characterized by elevated cerebrospinal fluid (CSF) pressure, papilledema, and normal CSF composition. The peak incidence is in the third decade of life. The major symptoms are generally severe headache, transient visual obscuration, blurred vision and horizontal diplopia, pulsatile tinnitus, and pain in the neck, shoulders, back and arms. Pseudotumor cerebri may be associated with identifiable etiological factors such as middle ear disease, chronic obstructive pulmonary disease, radical neck dissection, nonspecific infections, corticosteroid use or steroid withdrawal, or with other medications including vitamin A, tetracycline, and nalidixic acid. Pseudotumor cerebri is also associated with obesity and pregnancy. For example, the incidence is at least 1/100, 000 in the general population and increases to 19/100, 000 in obese women. The etiology of the increased CSF pressure is unknown, and diminished CSF absorption and cerebral edema have both been investigated as causes.

The major risk for a patient with pseudotumor cerebri is visual loss which occurs in 10% to 26% of patients. The primary cause of visual loss is progressive optic atrophy. Other causes include juxtapapillary choroidal neovascularization, preretinal hemorrhage, central retinal vein occlusion, macular edema (star), and chorioretinal folds. Our patient had both optic atrophy and choroidal neovascularization with associated exudative retinal detachment and macular edema as causes for visual loss in the left eye. The occurrence of juxtapapillary choroidal neovascularization is a rare event, and, to the best of our knowledge, only five cases have been reported so far, two of them bilateral. There have been no reports of subfoveal CNV excision in the setting of pseudotumor cerebri. An unusual feature of this case is that the CNV was identified before the papilledema was recognized clinically. However, bilateral fluorescein leakage from the optic nerve heads confirmed the presence of papilledema at the time the CNV was noted OS. The association of choroidal neovascularization with papilledema is not fully understood. Morse et al. suggested that physical deformation of the peripapillary tissues by papilledema may create the required pathway for the ingrowth of the neovascularization beneath the retinal pigment epithelium and the sensory retina. Furthermore, hypoxia, created by axonal swelling-induced impaired vascular perfusion, was suggested to contribute to the development of CNV.