Acquired hypocalciuric hypercalcemia in a patient with CKD

Elizabeth Kuo, E. Helen Kemp, Harpreet K. Sandhu, Edward M. Brown, Anthony P. Weetman, Chou Long Huang

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

We present a case of an 82-year-old woman with elevated parathyroid hormone (PTH) levels, hypocalciuria, hypercalcemia, and stage 3 chronic kidney disease. Hypocalciuria initially was attributed to chronic kidney disease, and hypercalcemia was attributed to primary hyperparathyroidism. Subsequent laboratory studies showed autoantibodies in the patient's serum directed against the calcium-sensing receptor (CaSR). Functional testing in a CaSR-transfected human embryonic kidney-293 cell line showed that the patient's antibodies inhibited CaSR-mediated intracellular signaling that ordinarily would have been stimulated by extracellular calcium ions. Her serum calcium and PTH levels were normalized by treatment with the calcimimetic cinacalcet. We advise consideration of the presence of inhibitory autoantibodies directed at the CaSR in patients with hypercalcemic hyperparathyroidism and unexplained hypocalciuria or with confounding conditions affecting interpretation of urinary calcium measurement. A calcimimetic is an effective treatment for the hypercalcemia and elevated PTH levels in acquired hypocalciuric hypercalcemia caused by inhibitory anti-CaSR autoantibodies.

Original languageEnglish (US)
Pages (from-to)1151-1154
Number of pages4
JournalAmerican Journal of Kidney Diseases
Volume62
Issue number6
DOIs
StatePublished - Dec 2013

Keywords

  • Autoimmune hypocalciuric hypercalcemia
  • autoantibody
  • calcium-sensing receptor
  • hyperparathyroidism

ASJC Scopus subject areas

  • Nephrology

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