[Phospho-calcium and bone metabolism in hyperthyroidism in adults].

The abnormalities of calcium-phosphorum metabolism observed in hyperthyroidism (tendency to hypercalcaemia with subsequent functional hypoparathyroidism, increase in serum alkaline phosphatase and in hydroxyprolinuria) essentially result from excessive mobilization of bone calcium and phosphates by the thyroid hormones themselves. Histomorphometric studies have shown that the skeletal repercussions of hyperthyroidism are almost constant. There is, in particular, excessive bone remodelling due to increased bone-forming and bone-resorbing cellular activities. However, since bone resorption is quantitatively more stimulated than bone formation, the physiological bone loss is accelerated and is only partly repaired by re-establishment of the normal thyroid function.