Increased calcium tolerance in patients with tetania latenta.

We studied the calcium tolerance on 59 subjects with tetania latenta. The calcium tolerance was tested by induced hypercalcemia (Klotz's test). In 12 cases the dynamic changes of serum magnesium were also investigated during the same test. Eight cases exhibited a normal tolerance and 51 exhibit an abnormal response, calcemia remaining at a high value after 4 hours of the test. The magnesium values remained low when finishing the test (p less than 0.001). It was concluded that 86 per cent of the subjects having tetania latenta and exhibiting an increase of calcium tolerance had a possible calcitonin deficiency. The significance of the magnesium decrease remains unclear. These phenomena have not been observed in Graves' disease and in the Turner's syndrome.