Hypercalcemia (hypercalcaemia)

Mayo Clinic overview

Hypercalcaemia - presentation and management ¹⁾

Hypercalcaemia is a common disorder normally caused by primary hyperparathyroidism (PHPT) or malignancy. A proportion of cases present as an emergency, which carries a significant mortality. Emergency management of hypercalcaemia is based on intravenous rehydration with normal saline but when this is inadequate, bisphosphonate therapy is used; more recently the novel anti-resorbtive agent denosumab has been shown to have a useful role in treatment.

Although parathyroidectomy is the only curative treatment for PHPT, this is indicated in a minority of cases.

Hyperuricaemia was associated with an unfavourable cardiovascular risk profile in HF patients. Treatment with low doses of allopurinol did not improve the prognosis of HF patients. ²⁾

A Quick Reference on Hypercalcemia. ³⁾

In dogs, neoplasia is the most common cause of hypercalcemia, followed by primary hyperparathyroidism, chronic kidney disease, and hypoadrenocorticism. In cats, idiopathic hypercalcemia is the most common cause, followed by chronic kidney disease and then neoplasia.

Cancer-Related Hypercalcemia. ⁴⁾

The most common causes include humoral hypercalcemia of malignancy mediated by parathyroid hormone-related peptide, osteolytic cytokineAny of various protein molecules secreted by cells of the immune system that serve to regulate the immune system. production, and excess 1,25-dihydroxy vitamin D production.

The active form of vitamin D3Form of vitamin D made in the skin when exposed to light. Also available in fish and meat. This secosteroid is sometimes converted into 25-D. Also known as cholecalciferol and activated 7-dehydrocholesterol. , calcitriol, is a potent antiproliferative compound. However, when effective antitumor doses of calcitriol are used, hypercalcemic effects are observed, thus blocking its therapeutic application. ⁵⁾

Vitamin D: Metabolism, Molecular Mechanism of Action, and Pleiotropic Effects. ⁶⁾

CYP2R1 has been identified as the most important 25-hydroxylase, and a critical role for CYP24A1 in humans was noted in studies showing that inactivating mutations in CYP24A1 are a probable cause of idiopathic infantile hypercalcemia.

Successful treatment of an intra-pelvic fungal pseudomycetoma causing constipation and hypercalcaemia in a Persian cat. ⁷⁾

Since calcitriol (the active form of vitamin D) is a Vitamin D receptorA nuclear receptor located throughout the body that plays a key role in the innate immune response. (VDRThe Vitamin D Receptor. A nuclear receptor located throughout the body that plays a key role in the innate immune response.) agonist, and use of this substance can cause hypercalcemia, one may expect that olmesartanMedication taken regularly by patients on the Marshall Protocol for its ability to activate the Vitamin D Receptor. Also known by the trade name Benicar. , through effects on the VDR, may also cause hypercalcemia if the dosage is high. There is however no evidence that this is an effect of olmesartan, and the reason for the differing effects appears to reside in the non-VDR effects of calcitriol. ⁸⁾