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Abnormal calcium metabolism caused by increased circulating 1,25‐dihydroxyvitamin D in a patient with rheumatoid arthritis
Author(s) -
Gates Sherman,
Shary Judith,
Turner Russell T.,
Wallach Stanley,
Bell Norman H.
Publication year - 1986
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.5650010209
Subject(s) - medicine , endocrinology , hypercalciuria , vitamin d and neurology , rheumatoid arthritis , sarcoidosis , parathyroid hormone , calcium metabolism , calcium
A 35‐year‐old white male with rheumatoid arthritis who had developed hypercalcemia, hypercalciuria, and nephrolithiasis was found to be abnormally sensitive to vitamin D as a result of lack of regulation of circulating 1,25‐dihydroxyvitamin D (1,25‐(OH) 2 D). An increase in daily intake of vitamin D from 10 μg (400 units) per day to 50 μg (2000 units) per day produced an abnormal elevation in serum 1,25‐(OH) 2 D, hypercalcemia, and hypercalciuria which were corrected by prednisone. Serum 25‐hydroxyvitamin D initially was abnormally low, and increased with vitamin D to values which were in the low normal range. There were significant positive correlations between serum 1,25‐(OH) 2 D ( p < .05) and serum calcium and between serum 1,25‐(OH) 2 D and urinary calcium ( p < .05). Serum immunoreactive parathyroid hormone, initially in the lower range of normal, decreased further during hypercalcemia. A radiograph of the chest, gallium scan, and serum angiotensin‐converting enzyme activity were normal. No granulomas or evidence of lymphoma were found in biopsies of the liver and of several lymph nodes. It is concluded that the abnormal calcium metabolism in this patient resulted from increased circulating 1,25‐(OH) 2 D and that the defect in vitamin D metabolism was not related to sarcoidosis, other granulomatous disease, Hodgkin's disease, or lymphoma. The relationship, if any, of the abnormal metabolism of vitamin D and calcium to rheumatoid arthritis remains to be established.