Loss of motility predicts vision loss in Graves'.
Loss of vision is the most serious complication of Graves' ophthalmopathy. It may become irreversible if left untreated. In a series of 137 consecutive patients with severe Graves' ophthalmopathy, loss of vision occurred in 18, said Dr. Laurberg, professor of endocrinology at Aarhus (Denmark) University.
Reduced eye motility in more than two directions was present in 14 of 18 patients who developed loss of vision, compared with just 20 of 119 without this complication. In a multivariate regression analysis, the presence of reduced eye motility in more than two directions was associated with nearly a 10-fold increased risk of loss of vision, compared with the risk associated with reduced eye motility in two or fewer directions, he said.
Patients with loss of vision experienced a mean 50% reduction in visual acuity in the affected, compared with the unaffected eye.
Factors that proved unrelated to loss of vision in patients with severe Graves' ophthalmopathy included age, body weight, type of thyroid dysfunction, smoking status, duration of Graves' ophthalmopathy and thyroid disease, antithyroid antibody levels, and the presence of double vision or ocular proptosis. Increased ocular tension and more extensive orbital inflammation were associated with loss of vision in a univariate analysis but became nonsignificant in the multivariate analysis.
CT scanning studies have shown that reduced eye motility in more than two directions corresponds to more than two external eye muscles being severely affected by Graves' ophthalmopathy.
In a separate presentation, Vahab Fatourechi, M.D., reported that 18% of patients free of Graves' ophthalmopathy at the time they undergo radioactive iodine therapy for Graves' disease will develop the condition within 5 years. But whether it is a side effect of the radioactive iodine or a result of the natural history of Graves' disease remains unresolved.
He presented a retrospective study of 119 patients who received radioactive iodine (RAI) therapy for Graves' disease with the intent of achieving hypothyroidism during 1990-1993 at the Mayo Clinic, Rochester, Minn. Ten percent had Graves' ophthalmopathy at the time of treatment.
Risk factors for new-onset Graves' ophthalmopathy during 5 years of follow-up were higher levels of thyroid-stimulating immunoglobulin and an extensive smoking history. Among women, who comprised 77% of the study population, each pack-year of tobacco use was associated with an additional 2.6% increase in risk.
Among US physicians, RAI is a popular choice for the treatment of Graves' disease because of its relative lack of side effects and low cost.
In Europe and elsewhere, however, patients often undergo thyroidectomy or treatment with antithyroid medications as first-line therapy. Some nondefinitive studies suggest that RAI may aggravate Grave's ophthalmopathy, so the combination of corticosteroids and RAI has been gaining popularity.
George J. Kahaly, M.D., emphasized that patients with Graves' ophthalmopathy not only experience physical illness, but emotional distress and even psychiatric illness as a result of the physical disfigurement. He reported on 102 consecutive patients with Graves' ophthalmopathy who completed the Hospital Anxiety and Depression Scale as well as the Short Form-36 to assess quality of life. The results were compared with normative values as well as the scores recorded in 102 patients with type 1 diabetes and 102 others with inflammatory bowel disease.
Of patients with Graves' ophthalmopathy, 45% showed high levels of emotional distress warranting psychiatric treatment. Scores on all domains of the SF-36 were significantly lower in the Graves' group than the age- and gender-adjusted normative values. Psychosocial scores on the SF-36 were significantly lower in the Graves' and bowel disease groups than the diabetics, said Dr. Kahaly of Gutenberg University, Mainz, Germany.
ARTICLES BY BRUCE JANCIN
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|Publication:||Internal Medicine News|
|Date:||Dec 1, 2004|
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