Definition: WHAT: Hyperparathyroidism. Hyperparathyroidism: a condition due to an increase in the secretion of the parathyroids, causing generalized osteitis fibrosa cystica, elevated serum calcium, decreased serum phosphorus, and increased excretion of both calcium and phosphorus. WHY: Several rheumatological disorders are associated with hyperpara- thyroidism. First, hyperuricemia and gouty arthritis (which may mimic hyperparathyroidism with renal stone formation and colic) have an increased incidence in patients with hyperparathyroidism. Second, patients with primary hyperparathyroidism show an increased incidence of chondrocalcinosis with episodes of calcium pyrophosphate crystal induced synovitis. Approximately 25% of patients with hyperparathyroidism will show radiographic evidence of calcification of articular cartilage and joint capsules. Finally, there can be a synovial and cartilaginous lesion ("osteogenic synovitis") in patients with hyperparathyroidism which may mimic other primary rheumatic diseases such as rheumatoid arthritis. In osteogenic synovitis there is softening and collapse of subchondral bone. Eventually the cartilage overlying this area erodes and is replaced by an irregular fibrocartilage. Eventually the articular surface of the joint is destroyed and secondary degenerative arthritis may develop. REFS: 1) Zvaifler, NJ; Reefe, WE and Black, RL: Articular manifestations in primary hyperparathyroidism. Arthritis Rheum 5:237, 1962. 2) Scott, JT; Dixon, ASJ and Bywaters, EGL: Association of hyperuricemia and gout with hyperparathyroidism. Br Med J 1:1070, 1964. 3) Bywaters, EGL and Scott, JT : Joint lesions of hyperparathyroidism. Ann Rheum Dis 22:171-87, 1963.
Synonyms (terms occurring on more labels are shown first): hyperparathyroidism