Abstract

THYROID ASSOCIATED ORBITOPATHY- A REVIEW

*D. Sai Aravind, N. Varshitha, Dr. G. Susmitha, Dr. V. Tejaswi, Dr. P. Srinivasa Babu

ABSTRACT

Thyroid-associated orbitopathy (TAO), frequently termed Graves ophthalmopathy, is part of an autoimmune process that can affect the orbital and periorbital tissue, the thyroid gland, and, rarely, the pretibial skin or digits (thyroid acropachy) and characterised by enlargement of the extraocular muscles and increase in fatty or connective tissue volume. The most significant pathological findings in TAO include glycosaminoglycan (GAG) deposition (accompanied by swelling resulting from the hydrophilic capacity of these macromolecules), fibrosis affecting the extraocular muscles, and adipogenesis in the orbit. To date, there are no effective means of preventing the disease or reliably altering its course. There appears to be a female preponderance in which women are affected 2.5-6 times more frequently than men; however, severe cases occur more often in men than in women. The disease can manifest as predominantly fat expansion or with isolated extraocular muscle (EOM) involvement or most commonly a mixture of both. Fibroblasts can be identified on the basis of cell surface markers such as Thy-1 and CD34. Subsets differ in their ability to differentiate into adipocytes or myofibroblasts. Cells from orbital fat differ phenotypically from those of perimysial derivation. TAO is associated with accelerated glycosaminoglycan production, resulting in mechanical embarrassment of the orbital contents. Orbital fibroblast proliferation and differentiation into adipocytes leads to fat tissue expansion. In this article we want to give a complete on this disorder.

Keywords: orbitopathy, hyperthyroidism, fibroblasts, extraocular muscle.