Are all animals with renal disease azotaemic?
Animals with impaired urine concentration due to renal disease may or may not be azotaemic depending on the percentage of nephron loss-loss of 67% of nephron function results in impaired concentration ability, loss of 75% results in azotaemia. Is a water-deprivation test useful? Although it is often assumed that a water-deprivation test is useful in diagnosing compensated renal disease, it should be remembered that the animal with compensated renal disease may become seriously azotaemic if water is deprived and dehydration ensues. As previously mentioned, disorders such as hyperadrenocorticism may also impair the animal’s ability to concentrate urine in the face of dehydration and hence the test may not be particularly discriminatory. It is preferable to rule out other possible disorders with appropriate tests (urea, creatinine, liver enzymes, calcium, electrolytes, T4 and WBC). If these tests are all normal and there are no other clinical signs, compensated renal disease is the probab
