Case reportIdiopathic calcitriol-induced hypercalcemia
Introduction
Hypercalcemia is a relatively common clinical problem. Primary hyperparathyroidism and cancer account for 95% of cases [1]. An extensive differential diagnosis remains after exclusion of these causes. An important category comprises the chronic granulomatous disorders, in particular sarcoidosis, in which hypercalcemia is caused by increased production of calcitriol (1,25-(OH)2vitaminD3) [2]. A rare cause of hypercalcemia is idiopathic excess production of calcitriol in the apparent absence of granulomatous disease, so called idiopathic calcitriol-induced hypercalcemia, which is presented in this report [3].
Section snippets
Case report
A 78-year-old man was referred to our department because of fatigue and weight loss. One year before coronary bypass grafting was performed, otherwise his medical history was unremarkable. The results of physical examination were normal except for an insignificant systolic heart murmur.
Laboratory tests disclosed the following values: erythrocyte sedimentation rate, 28 mm/h; hemoglobin, 10.1 g/dL; mean corpuscular volume (MCV), 82 fl.; other blood cell counts were normal. Hypercalcemia and renal
Discussion
Our patient presented with symptomatic hypercalcemia. The first step in the evaluation of hypercalcemia is measurement of the serum PTH level. This was adequately suppressed, ruling out primary hyperparathyroidism. Second, a malignancy had to be excluded which was extensively done in our case.
Next, vitamin D3 levels were determined which yielded high serum concentrations of calcitriol. Hypercalcemia can be caused by increased endogenous production of calcitriol, as occurs in patients with
Learning points
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Primary hyperparathyroidism and cancer account for 95% of cases of hypercalcemia.
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A rare cause of hypercalcemia is idiopathic excess production of calcitriol associated with elevated serum ACE levels, without evidence of granulomatous disease.
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Treatment of idiopathic calcitriol-induced hypercalcemia consists of corticosteroids.
References (4)
Vitamin D metabolite-mediated hypercalcemia
Endocrinol Metab Clin North Am
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N Engl J Med
(1994)
Cited by (4)
Rare causes of calcitriol-mediated hypercalcemia: A case report and literature review
2010, Journal of Clinical Endocrinology and MetabolismA case of severe 1,25-dihydroxyvitamin D-mediated hypercalcemia due to a granulomatous disorder
2012, Journal of Clinical Endocrinology and Metabolism