Persistent hypercalcemia after parathyroidectomy in an adolescent and effect of treatment with cinacalcet HCl.

Author(s): Henrich LM, Rogol AD, D'Amour P, Levine MA, Hanks JB, Bruns DE

Affiliation(s): Department of Pathology, University of Virginia Medical School, Charlottesville, VA 22908, USA. lmh5p@virginia.edu

Publication date & source: 2006-12, Clin Chem., 52(12):2286-93. Epub 2006 Nov 14.

Publication type: Case Reports; Clinical Conference

BACKGROUND: Hyperparathyroidism is uncommon in adolescence and is more likely to persist after parathyroidectomy than in adults. Cinacalcet HCl is a new calcimimetic that has been used successfully for the treatment of primary and secondary hyperparathyroidism in adults, but its use in adolescents has not been reported. Case: A 16 year-old male presented with hypercalcemia that had persisted for 1.5 years after parathyroidectomy for primary hyperparathyroidism. Parathyroid hormone (PTH) concentrations were nonsupressed despite a mean (SD) serum calcium concentration of 2.82 (0.06) mmol/L. Treatment with cinacalcet HCl was initiated and a pharmacodynamic profile was obtained for serum calcium, phosphorus, and PTH. Cinacalcet HCl normalized serum calcium. The changes in PTH were assay dependent. Issues: We use this case conference to review the evaluation of hypercalcemia in adolescents, examine the changes in relevant laboratory results during treatment with cinacalcet HCl, and discuss differences among assays for PTH. CONCLUSIONS: Interpretation of PTH results in patients treated with cinacalcet HCl requires consideration of the pharmacodynamic effects of the drug and the nature of the PTH assay.