Investigation of polyuria and polydipsia in the dog

POLYURIA and polydipsia are two common presenting signs in dogs seen in practice. There are a number of causes and these can be divided into two groups: primary polyuria/secondary polydipsia and primary polydipsia/secondary polyuria. Some causes may produce clinical signs by more than one mechanism. Compensatory mechanisms that regulate water homeostasis mean that polyuria and polydipsia always occur together. Careful history taking and hospital monitoring are required to demonstrate polyuria or polydipsia. This article describes the approach to the investigation of canine polyuria and polydipsia, and discusses some of the procedures which may aid diagnosis.