Diseases associated with calcium pyrophosphate dihydrate crystal deposition: A controlled study

Abstract

A comparison of the frequency of hypertension, diabetes mellitus, urate gout, hemochromatosis, azotemia and hyperparathyroidism in 28 pseudogout patients and 22 control subjects with osteoarthritis of the large weight-bearing joints failed to provide statistical evidence of intergroup differences. This may be related to the relatively small number of patients studied and the relatively low incidence of the associated diseases as three patients had findings suggestive of mild, clinically inapparent hemochromatosis, three had histologically proved or chemical hyperparathyroidism and three had urate gout in the pseudogout group. None of the control subjects had hemochromatosis, two had urate gout, and one patient with osteoarthritis had chemical hyperparathyroidism. Immunoreactive parathyroid hormone (PTH) levels were increased in most patients in both groups; serum calcium levels correlated significantly with the PTH values, as did roentgenographic evidence of knee joint degeneration in the women patients. If the associated diseases are causally related to calcium pyrophosphate crystal deposits, these findings suggest that pseudogout, like urate gout, has multiple etiologies. A hypothesis relating the possible effects of sustained low grade hyperparathyroidism to the genesis of the articular lesions has been advanced.