A case of severe 1,25-dihydroxyvitamin D-mediated hypercalcemia due to a granulomatous disorder.

Abstract

BACKGROUND:

Profound hypercalcemia is usually due to underlying malignancy.

CASE:

We describe a case of granulomatous myositis presenting with extreme hypercalcemia of 20.1 mg/dl and generalized weakness that did not resolve despite rapid correction of serum calcium. The disease process was unmasked by cholecalciferol supplementation. Initial search for a malignant process yielded no diagnosis, but an elevated 1,25-dihydroxyvitamin D level, in the setting of a suppressed PTH and undetectable PTHrP, pointed to the presence of excessive 1α-hydroxylase activity.

METHODS AND RESULTS:

Biopsy of the vastus lateralis muscle showed extensive granulomatous myositis. Immunohistochemical staining for 1α-hydroxylase was localized to the multinucleated giant cells and histiocytes. Musculoskeletal magnetic resonance imaging showed involvement of proximal muscle groups of both thighs and upper limbs.

CONCLUSION:

Measurement of vitamin D metabolites is pivotal in diagnosing 1,25-dihydroxyvitamin D-mediated hypercalcemia. Granulomatous disease can occasionally cause profound hypercalcemia and needs to be considered in the differential diagnosis. 1,25-Dihydroxyvitamin D-mediated hypercalcemia is responsive to glucocorticoid therapy.

• Authors: Jane Tong Wen Zhang, Charles Chan, Sun Young Kwun, Katherine Ann Benson
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) Vol. 97 Issue 8 Pg. 2579-83 (Aug 2012) ISSN: 1945-7197 [Electronic] United States
• PMID: 22639294 (Publication Type: Case Reports, Journal Article)

Chemical References

• Vitamin D
• 1,25-dihydroxyvitamin D

Topics

• Aged
• Female
• Granuloma (complications)
• Humans
• Hypercalcemia (etiology, therapy)
• Myositis (complications)
• Sarcoidosis (complications)
• Vitamin D (analogs & derivatives, physiology)