The severity of hypercalcaemic symptoms is related both to the degree of elevation in the ionized calcium level and to the rapidity with which the calcium level rises.
Hypercalcemia can also cause nephrogenic diabetes insipidus due to the stimulation of the calcium-sensing receptor (CaSR) in the collecting ducts of the kidney. Consequently, patients with hypercalcaemia frequently report symptoms of polyuria and polydipsia.