Endocrine Abstracts

Pretibial myxoedema (thyroid-associated dermopathy), an extrathyroidal manifestation of Graves disease, is a localized thickening of the skin due to accumulation of acid mucopolysacharides (glycosaminoglycans). Almost invariably, pretibial myxoedema occurs in the presence of ophthalmopathy.

We report the case of a 57-year-old man of North African origin, who presented with pretibial myxoedema as the first manifestation of Graves disease. He was admitted with weight loss, night sweats and a non-productive cough. He had painful shins. In addition to chest signs he also had plaques on the lower legs in the absence of other physical findings of Graves disease. Chest x-ray showed hilar lymphadenopathy with right-sided pleural effusion. His serum calcium was elevated at 2.83 millimoles per liter (Normal range 2.20-2.70). Initial investigations were performed in order to exclude tuberculosis, sarcoidosis or malignancy. He was subsequently confirmed to be thyrotoxic with a suppressed TSH (thyroid stimulating hormone) less than 0.03 milli-units per liter (Normal range 0.25 - 5.55) and elevated serum FT4 of 57.7 micromoles per liter (Normal range 9.7 - 25.7) and FT3 of 21.7 micromoles per liter (Normal range 3.7 - 6.9). Thyroid peroxidase antibodies were negative. There was no evidence of thyroid eye disease. Treatment was commenced using a block and replace regimen with carbimazole and thyroxine. He developed severe thyroid eye disease six months later requiring treatment with high dose steroids.

In our patient, pretibial myxoedema was the earliest clinical manifestation leading to the diagnosis of Graves disease. Pretibial myxoedema rarely occurs in isolation from thyroid eye disease. Thyroid eye disease should be anticipated in any patient presenting with pretibial myxoedema as the sole extrathyroidal manifestation of Graves disease.