Hypercalcaemia secondary to elevated 1,25 dihydroxycholecalciferol in a dog with immune‐mediated polyarthritis

A seven-year-old male entire Bearded Collie was referred following a three-week history of pyrexia, lethargy and stiffness, which was poorly responsive to antibiotic therapy. The most significant laboratory abnormalities included marked neutrophilia and ionised hypercalcaemia. The dog was diagnosed with primary immune-mediated polyarthritis, which responded to prednisolone and azathioprine, and resulted in resolution of the elevated 1,25 hydroxycholecalciferol, hypercalcaemia and neutrophilia. To the authors' knowledge, this represents the first case report of hypercalcaemia secondary to immune-mediated polyarthritis.