tailieunhanh - Fundamentals of Clinical Ophthalmology (part 7)

Bệnh Dysthyroid mắt là nguyên nhân phổ biến nhất của proptosis ở người lớn và bệnh thường trình bày như là bệnh Graves trong thập kỷ thứ ba và thứ tư, với ưu thế gấp bảy lần bốn ở phụ nữ. Viêm quỹ đạo là song phương thường kèm theo co rút mí mắt và hạn chế của các phong trào mắt. | 11 Dysthyroid eye disease Carol Lane Dysthyroid eye disease is the commonest cause of proptosis in adults and the disease typically presents as Graves disease in the third and fourth decade with a four- to seven-fold predominance in females. Bilateral orbital inflammation is often accompanied by eyelid retraction and restriction of ocular movements. Asymmetrical involvement and extensive fibrosis are less frequent presentations and the diagnosis of dysthyroid eye disease should always be suspected in the presence of any inflamed orbit or with proptosis. Sight is threatened by corneal exposure due to incomplete eyelid closure over a proptotic globe uncontrolled ocular hypertension or optic nerve compression. One-fifth of patients with untreated compressive optic neuropathy develop irreversible visual impairment to 6 36 or less . Treatment of dysthyroid eye disease aims to conserve or restore normal visual function relieve ocular pain and achieve an acceptable appearance. Pathogenesis In Graves hyperthyroidism it is likely that thyroid damage leads to activation of autoimmune thyroid disease by activation of anti-receptor antibodies to the thyrotrophin receptor TSH receptor . Eye disease is clinically evident in 40 of patients with Graves disease but in contrast in only 3 of patients with Hashimoto s thyroiditis and very 112 rarely with primary hypothyroidism. The high correlation between Graves disease and orbital disease suggests a shared antigen such as TSH receptor thyroglobulin or thyroid peroxidase. Circulating activated T lymphocytes infiltrate the orbital tissues where they release cytokines which in turn stimulate proliferation of fibroblasts and deposition of glycosaminoglycans GAGs . Intense lymphocytic infiltration fibroblast proliferation and perimysial oedema result in expansion of orbital contents and proptosis. Subsequent fibrosis of involved perimysial connective tissue results in varying degrees of muscular contracture. Hales and Rundle described .