title: Primary hyperparathyroidism and severe hypercalcemia with low circulating 1,25-dihydroxyvitamin D.
abstract: We report a postmenopausal woman with primary hyperparathyroidism (PHPT) and severe hypercalcemia while her total calcium intake was more than 2 g daily. Despite a markedly elevated intact PTH level, her serum 1,25-dihydroxyvitamin D [1,25-(OH)2D] level was low (17 pmol/L; 7 pg/mL). With reduced calcium intake, her serum calcium normalized, and 1,25-(OH)2D increased to 122 pmol/L (51 pg/mL). At the same time, intact PTH decreased to 32% of the initial value. PHPT may be associated with low circulating 1,25-(OH)2D levels. Furthermore, low 1,25-(OH)2D levels in PHPT may be due to a direct effect of severe hypercalcemia and be reversible with correction of hypercalcemia.
authors.affiliation: Department of Medicine, St. Luke's Medical Center, Milwaukee, Wisconsin 53215.
authors.forename: J L
authors.initials: JL
authors.lastname: Shaker
authors.forename: K W
authors.initials: KW
authors.lastname: Krawczyk
authors.forename: J W
authors.initials: JW
authors.lastname: Findling
mesh_terms: D000368:Aged; D002117:Calcitriol / Q000097:blood*; D002118:Calcium / Q000097:blood; D002136:Calcium, Dietary / Q000032:analysis; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood* / Q000150:complications; D006961:Hyperparathyroidism / Q000097:blood* / Q000150:complications; D010281:Parathyroid Hormone / Q000097:blood
chemical_list: D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D002117:Calcitriol; D002118:Calcium