Investigating hypercalcaemia in cats and dogs

Background: Hypercalcaemia is an important biochemical abnormality in dogs and cats and can lead to a wide variety of clinical signs, including polyuria, polydipsia and vomiting. It can be caused by several diseases of which the prognoses are variable. Both dogs and cats should undergo appropriate investigations, and cat owners in particular must be prepared for likely extensive investigation, excluding all known aetiologies, before a potential diagnosis of idiopathic hypercalcaemia. Understanding calcium physiology and pathophysiology can help both the general practitioner and referral practitioner streamline their investigation and achieve a rapid diagnosis. Hypercalcaemia has a well-defined list of differential diagnoses and methodical investigation will allow the clinician to optimise patient outcome. Aim of the article: This article describes a stepwise approach to the investigation of patients with ionised hypercalcaemia, and highlights some of the key differences between dogs and cats.