**4.6. Super antigens**

Super antigens are endogenous or exogenous proteins such as microbial proteins, capable of stimulating a strong immune response through molecular interactions with non-variant parts of the T- cell repertoire and the HLA class II proteins.

Thyroid Hormone Excess: Graves' Disease 167

thyroiditis. Thrill and bruit can be present over goiter in severe cases and it is due to increased vascularity of the gland. Thrill and bruit are present usually on upper or lower pole and continuos in nature, but sometimes can present only in systole. Large goiter with intrathoracic extension can be associated with facial swelling and flushing, and neck vein

Graves' ophthalmopathy is one of the distinctive manifestations of Graves' disease. Overall clinical ophthalmopathy is present in about 50% of Graves' disease patients,29 however CT or MRI reveals extraocular muscle enlargement in about 70% of patients without overt clinical ophthamopathy.30,31 Bimodal age distribution was noted for ophthalmopathy in both men and women. Peak age is 40 to 44 years and 60 to 64 years in women, whereas in men it

There is no specific genetic predisposition for graves' ophthalmopathy. Environmental

Smoking is a major risk factor for ophthalmopathy. Smoking also increases the risk for worsening of ophthalmopathy after radioiodine treatment. Possible contributors are orbital

Graves' disease is predominantly a disease of females (F: M= 8-10:1). In comparison to Graves' disease, ophthalmopathy is relatively more common in males (F: M= 1:1.8-2.8) than

Graves' disease patients treated with radioiodine are at increased risk for onset and worsening of eye disease, as compared to antithyroid drugs alone. 36,37 This risk can be

Current evidence support an autoimmune pathogenesis with important environmental influences, particularly smoking. Orbital muscles, connective tissues, and adipose tissues are infiltrated by lymphocytes and macrophages. TH1 mediated immune response predominates in early stage of disease while TH2 response predominates in late stage. 40 In response to cytokines secreted by the infiltrating immune cells, orbital fibroblasts start synthesizing and secreting hydrophilic glycosaminoglycans, resulting in edema of orbital

distension upon raising the arm above the head. This is known as Pemberton sign.

**6.2. Graves' ophthalmopathy** 

is 45 to 49 years and 65 to 69 years.

*Smoking* 

*Gender* 

females. 34,35

*Radioiodine* 

*6.2.2. Pathogenesis* 

*6.2.1. Risk factors for Graves' ophthalmopathy* 

factors are more important for ophthalmopathy.

hypoxia and free radical present is smoke. 32,33

decreased by concurrent use of corticosterodis.38,39
