July 16, 2003
The presence of white matter lesions on baseline MRI is the most potent predictor of multiple sclerosis (MS) in patients with acute unilateral optic neuritis, according to findings reported in the July issue of the Archives of Ophthalmology.
In contrast, when patients with optic neuritis exhibit severe optic disc edema, peripapillary hemorrhage or retinal exudates accompanied by normal MRI findings, they are unlikely to develop MS during the next 10 years, according to results of the Optic Neuritis Treatment Trial.
The new findings highlight the importance of a dilated fundus examination and MRI at presentation, Dr. Roy W. Beck, of the Jaeb Center for Health Research in Tampa, Florida, and colleagues, note.
Members of the Optic Neuritis Study Group prospectively followed 388 patients who initially experienced acute optic neuritis between 1988 and 1991. The 160 patients who had at least one lesion measuring 3 mm in diameter or more on their baseline MRI had a 56% risk of developing MS during 10 years of follow-up.
"However, the presence of 1 or more lesions did not signify that the patient was destined to develop multiple sclerosis," the group points out. Conversely, the absence of such lesions did not eliminate the risk, since the 10-year probability in this subgroup was 22%.
None of the patients with painless or total visual loss, or who had severe disc swelling, hemorrhages, or exudates, developed MS during follow-up. Therefore, the authors conclude, "In patients who bear these atypical features, the optic neuritis may not be part of a multifocal demyelinating central nervous system illness."
In fact, these patients may not have optic neuritis at all, Dr. Leonard A. Levin, of the University of Wisconsin Medical School in Madison, and Dr. Simmons Lessell in Boston write in an accompanying editorial. For example, symptoms may be due to nonarteritic anterior ischemic optic neuropathy, neuroretinitis or papillophlebitis.
Therefore, they recommend that treatment with interferon-beta or glatiramer acetate be deferred for patients with atypical optic neuritis with normal MRIs. On the other hand, Drs. Levin and Lessell conclude, "even a single brain lesion on a T2-weighted MRI scan is sufficient to consider initiating immunomodulatory treatment in a patient with typical optic neuritis."
Arch Ophthalmol 2003;121:944-949.
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