Rheumatologisch-osteologische Aspekte bei Schilddrüsenerkrankungen

Abstract

Thyroid diseases are often associated with symptoms of the locomotive system on one hand and with various rheumatic diseases on the other. An increased prevalence of autoimmune thyroid diseases is observed in primary Sjogrens syndrome, rheumatoid arthritis, juvenile chronic arthritis, systemic sclerosis, systemic lupus erythematosus and fibromyalgia. A strong pathogenetic relationship between thyroid function and the co-existing rheumatic disease is lacking. On the other hand, various unspecific rheumatic symptoms are observed frequently in hyperthyroidism and hypothyroidism. These include mild non-erosive arthritis, polyarthralgia and myalgia in autoimmune thyroiditis and adhesive capsulitis of the shoulder in hyperthyroidism. Especially in patients with long-lasting Graves disease with orbitopathy, thyroid acropachy can occur. About 2 % of Asian people with thyrotoxicosis may suffer from thyrotoxic periodic paralysis. Typical manifestations of hypothyroidism are carpal tunnel syndrome and hypothyroid myopathy which is associated with elevated creatine kinase and should be considered in differential diagnosis of polymyositis. A very important manifestation of thyroid disease is osteoporosis in hyperthyroidism. Both an excess of thyroid hormone and a deficiency of thyroid-stimulating hormone are involved in high bone turnover and bone loss. In hyperthyroid subjects, a reduction of 12 - 15 % in bone mineral density has been shown. Risk factors for bone loss in subclinical hyperthyroidism are older age, menopausal state, a long-lasting TSH suppression and the combination with other risk factors for osteoporosis. Overt and subclinical hyperthyroidism should be considered in the differential diagnosis of osteoporosis in general. An early treatment of hyperthyroidism is effective in the prevention of bone loss. With regard to bone metabolism, a TSH-suppression during T 4-therapy should be avoided if possible. If TSH suppression is indicated, the prophylactic use of bisphophonates should be considered.