[Osteoarthropathies and Myopathies associated with Disorders of the Thyroid Endocrine System].

Triiodothyronine (T3) is a key regulator of bone, muscle and articular cartilage. Musculoskeletal symptoms of hyperthyroidism include loss of bone mass finally leading to osteoporosis and weakness of the skeletal musculature. Hypothyroidism on the other side frequently leads to muscle stiffness and cramping and, occasionally, results in rhabdomyolysis. To prevent terminal differentiation of chondrocytes with consecutive cartilage degeneration, cartilage probably depends on exact regulation of local T3 availability by the intracellular deiodinase system. Recent findings underline the importance of local T3 generation by deiodinase type 2 and support the existence of local hypo- or hyperthyroidism.In the review, the implications of the recent literature for current understanding of osteoarthritis, myopathies and diabetic osteoarthropathy will be discussed. Further emphasis will be placed on the association of autoimmune thyroiditis with musculoskeletal diseases and fibromyalgia.