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Resistance to Calcitriol Therapy in Postsurgical Hypoparathyroidism
1293
lviETABOLISivl, E~JDOCR1NOLOGY Af
films were examined for pattern and amount of ossification. globular foci of smooth, A ossification is characterized radiopaque, rounded contoured areas in the central portions of extend to the perichondrium and costal cartilages, and involve the peristernal junctions. Type B ossification is characterized by irregular sheets of ossification beginning in the subperichondrial location, often marked at the costochondrial junction but without the central globular appearance of the type A pattern. The results show that 65 per cent of the women i::;60 years old had type A ossification and none of the 567 men had type A osssification. Type B ossification is restricted largely to women at as early ages as the mid thirties. F. T. A. 7 figures, 2 tables, 5 references
METABOLISM, ENDOCRINOLOGY AND IMMUNOLOGY Resistance to CalcHriol Therapy in Postsurgical HypopaI"athy:roidism K. SHAH, U.S. BARZEL, E. SCHWARTZ, M. HORWITH AND R. GOLDSTONE, Departments of Medicine, Montefiore Medical Center and the Albert Einstein College of Medicine, Bronx; New York Hospital and Cornell University Medical College, Manhattan, and Misericordia Hospital Medical Center and New York Medical College, Bronx, New York
N. Y. State J.
84: 255-256
1984
The hypocalcemia of post-thyroidectomy hypoparathyroidism in 2 patients responded oniy to extremely high doses of vitamin its metabolites or dihydrotachysteroL The ability to absorb calcitriol (dihydroxyvitamin D) or 25-hydroxyvitamin D was evaluated in 1 patient. Post-ingestion blood levels of these 2 substances were high but the serum calcium did not increase. The second patient had no clinical evidence of a malabsorption problem that would interfere with the bioavailability of the D vitamins. The individual with hypoparathyroidism has been shown previously to have a defect in the hydroxylation of the I-position of vitamin D, which resulted in an inadequate production of dihydroxyvitamin D. The success in the treatment of hypoparathyroidism with dihydroxyvitamin D and not with monohydroxyvitamin D has given additional evidence to this observation. Although the presence of dihydroxyvitamin D or the use of dihydrotachysterol will aid in attaining normocalcemia in the hypoparathyroid patient, the authors propose that another factor is equally important. They suggest that the parathyroid hormone itself acts synergistically with the vitamin metabolite to modify the absorption of calcium at the level of the intestinal epithelium. In the absence of this hormone only high doses of the vitamin D metabolite can aid in normalization of serum calcium. J. A. A. 15 references
lviETABOLISivl, E~JDOCR1NOLOGY Af
films were examined for pattern and amount of ossification. globular foci of smooth, A ossification is characterized radiopaque, rounded contoured areas in the central portions of extend to the perichondrium and costal cartilages, and involve the peristernal junctions. Type B ossification is characterized by irregular sheets of ossification beginning in the subperichondrial location, often marked at the costochondrial junction but without the central globular appearance of the type A pattern. The results show that 65 per cent of the women i::;60 years old had type A ossification and none of the 567 men had type A osssification. Type B ossification is restricted largely to women at as early ages as the mid thirties. F. T. A. 7 figures, 2 tables, 5 references
METABOLISM, ENDOCRINOLOGY AND IMMUNOLOGY Resistance to CalcHriol Therapy in Postsurgical HypopaI"athy:roidism K. SHAH, U.S. BARZEL, E. SCHWARTZ, M. HORWITH AND R. GOLDSTONE, Departments of Medicine, Montefiore Medical Center and the Albert Einstein College of Medicine, Bronx; New York Hospital and Cornell University Medical College, Manhattan, and Misericordia Hospital Medical Center and New York Medical College, Bronx, New York
N. Y. State J.
84: 255-256
1984
The hypocalcemia of post-thyroidectomy hypoparathyroidism in 2 patients responded oniy to extremely high doses of vitamin its metabolites or dihydrotachysteroL The ability to absorb calcitriol (dihydroxyvitamin D) or 25-hydroxyvitamin D was evaluated in 1 patient. Post-ingestion blood levels of these 2 substances were high but the serum calcium did not increase. The second patient had no clinical evidence of a malabsorption problem that would interfere with the bioavailability of the D vitamins. The individual with hypoparathyroidism has been shown previously to have a defect in the hydroxylation of the I-position of vitamin D, which resulted in an inadequate production of dihydroxyvitamin D. The success in the treatment of hypoparathyroidism with dihydroxyvitamin D and not with monohydroxyvitamin D has given additional evidence to this observation. Although the presence of dihydroxyvitamin D or the use of dihydrotachysterol will aid in attaining normocalcemia in the hypoparathyroid patient, the authors propose that another factor is equally important. They suggest that the parathyroid hormone itself acts synergistically with the vitamin metabolite to modify the absorption of calcium at the level of the intestinal epithelium. In the absence of this hormone only high doses of the vitamin D metabolite can aid in normalization of serum calcium. J. A. A. 15 references