Myxedema, pretibial

Dermopathy or pretibial myxedema will often respond to topical corticosteroids applied to the involved area and covered with an occlusive dressing. 

One of the manifestations of generalized or localized pretibial myxedema is a pronounced edema of the corium, with accumulation of mucinous material in the edema fluid. Both hyaluronic acid and a sulfated mucopolysaccharide fraction were isolated in increased quantity from the affected area of the skin of a patient with localized pretibial myxedema (Wl). Following this observation, the relationship between the functional status of the thyroid gland and the mucopolysaccharides of skin has been discussed in numerous publications. Analysis of the acid mucopolysaccharides of human skin has revealed the presence of dermatan sulfate, hyaluronic acid, and a small amount of chondroitin 4- or 6-sulfate (L9). 

A Methimazole has a longer TV2 than PTU and can be dosed once daily PTU requires three to four daily doses, which may affect compliance. PTU does not cause pretibial myxedema rather Graves hyperthyroidism leads to pretibial myxedema. Methimazole does not interact with amiodarone however, amiodarone can affect thyroid function, leading to both hypo- and hyperthyroidism. PTU therapy may result in spontaneous remission, but patients typically require therapy for many years (1 to 15 years). 

Graves disease " is an autoimmune syndrome that may include hyperthyroidism, diffuse thyroid enlargement, exophthalmos, pretibial myxedema, and thyroid acropachy (Figs. 73 and 73-5). Graves disease is the most common cause of hyperthyroidism. The prevalence of Graves disease is estimated to be 3 per... 

The thyroid gland is diffusely enlarged in the majority of patients and is commonly 40 to 60 g (two to three times the normal size). The surface of the gland is smooth and the consistency varies from soft to firm. In patients with severe disease, a thriU may be felt and a systolic bruit may be heard over the gland. The presence of any of the extrathyroidal manifestations of this syndrome including exophthalmos, thyroid acropachy, or pretibial myxedema in a thyrotoxic patient is pathognomonic of Graves disease (see Fig. 73-4). 

Imai Y, Odajima R, Shimizu T, Shishiba Y. Serum hyaluronan concentration determined by radiometric assay in patients with pretibial myxedema and Graves ophthalmopathy. Endocrinol Jpn 1990 37 749-752. 

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