Tetany due to hypomagnesaemia with secondary hypocalcaemia.

The case is described of a 5-month-old boy who had convulsions and persistent tetany, associated with hypomagnesaemia and hypocalcaemia. Vitamin D treatment corrected the hypocalcaemia without modifying the clinical status; parenteral magnesium was given, but the child died shortly thereafter. The pathological examination showed calcinosis of the myocardium, kidneys and in one of the cerebral arteries.