Myositis associated with the decline of thyroid hormone levels in thyrotoxicosis: a syndrome?
BACKGROUND
Musculoskeletal complaints are common in patients with thyroid dysfunction. Both thyrotoxic and hypothyroid myopathy have been well described, and there are distinct presentations, laboratory findings, and clinical outcomes between the two groups. Myopathy has also been reported in hyperthyroid patients only after beginning treatment, suggesting that relative hypothyroidism may also contribute to musculoskeletal disease. A confounding factor in these cases was that these patients were on antithyroid drugs that may also have direct effects on the muscle, irrespective of the rate of decline in thyroid hormone levels.


CONCLUSIONS
We report a patient with Graves' disease who developed myalgias with elevated creatine kinase levels after total thyroidectomy. Addition of triiodothyronine quickly resolved her symptoms and creatine kinase levels, whereas discontinuation of triiodothyronine, despite having normal to elevated total thyroxine levels, led to a relapse.


CONCLUSIONS
Myositis after correction of thyrotoxicosis may constitute a syndrome that should be assessed for in hyperthyroid patients complaining of myalgias after starting treatment.
Shaheen
Duha
D
Division of Endocrinology, Diabetes, and Metabolism, Tufts Medical Center , Boston, Massachusetts, USA.
Kim
Caroline S
CS
D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006111:Graves Disease / Q000150:complications*; D006801:Humans; D009220:Myositis / Q000209:etiology*; D013577:Syndrome; D013963:Thyroid Hormones / Q000378:metabolism*; D013965:Thyroidectomy; D013971:Thyrotoxicosis / Q000150:complications*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D013963:Thyroid Hormones; D014284:Triiodothyronine; D003402:Creatine Kinase; D013974:Thyroxine