Hypercalcemia associated with increased circulating 1,25 dihydroxyvitamin D in a patient with pulmonary tuberculosis

Abstract

Studies are described in a 53-year-old man with far-advanced pulmonary tuberculosis who developed transient increases in circulating 1,25 dihydroxyvitamin D (1,25(OH)₂D) and hypercalcemia while on antituberculous treatment. Serial dilution of an extract of the patient's serum obtained while he was hypercalcemic displaced [³H]-1,25(OH)₂D₃ from chick intestinal receptor in a manner identical to authentic 1,25(OH)₂D₃. Serum 25-hydroxyvitamin D (25OHD) was suppressed during the abnormal elevation of serum 1,25(OH)₂D. It is concluded that tuberculosis is another chronic granulomatous disease in which hypercalcemia may result from abnormal metabolism of vitamin D.