Hyperadrenocorticism in the dog

Canine hyperadrenocorticism is a common endocrinopathy resulting from excessive cortisol production by the adrenal cortex. This may be caused by either excessive adrenocorticotrophin hormone secreted by the pituitary gland, or less commonly by an adrenal tumour. Frequent presenting signs include dermatological changes, polydipsia, polyuria, a pendulous abdomen, excessive panting and weakness. Canine hyperadrenocorticism may be associated with a range of haematological, biochemical and urinary abnormalities. Although these changes may be suggestive of canine hyperadrenocorticism, a provocative test such as a low dose dexamethasone suppression test, or an adrenocorticotrophin stimulation test is necessary to obtain a definitive diagnosis. Either a high dose dexamethasone suppression test or an endogenous plasma adrenocorticotrophin level may then be necessary to differentiate pituitary dependent hyperadrenocorticism from an adrenal tumour.