Serum parathyroid hormone levels in patients with calcium pyrophosphate crystal deposition disease (chondrocalcinosis, pseudogout)

Abstract Immunoreactive parathyroid hormone was measured in the sera of 26 patients with calcium pyrophosphate crystal deposition disease, using a sensitive radioimmunoassay procedure. Elevated concentrations were found in the sera of 10 (38%) of these patients. Four of these 10 patients had hypercalcemia suggesting primary hyperparathyroidism, but 3 had hypocalcemia suggesting secondary hyperparathyroidism. The data extend the previously documented relationship between hyperparathyroidism and calcium pyrophosphate crystal deposition disease, but an explanation for the association is not readily apparent.