Reduced BUN-liver failure. Muffie drinks too much water because of psychogenic polydipsia. Renal medullary washout. Also called medullary solute washout. Ear Diseases of the Dog and Cat. That's in the low range of normal -- but normal all the same. The antidiuretic hormone regulates the ability of the kidney to concentrate urine. Also called medullary solute washout. The phenomenon is referred to as 'medullary washout" and the vet may have to find ways to retrain them through gradated water restriction. medullary J. Physiol. (5) Aldosterone deficiency in hypoadrenocorticism impairs NaCl reabsorption in the collecting ducts and contributes to medullary washout of solute. That's in the low range of normal -- but normal all the same. Hypotonic – loss of hyperosmolar fluid. This provides an osmotic gradient favoring the reabsorption of water into the medulla. The first thing we need to do is confirm that the drinking and urinating is actually excessive. vitro solubilisation and mechanical kinetics of Diagnostic Approach to Otitis in Dogs - Today's Veterinary Practice Dogs dog Water consumption and urine production controlled by: Plasma osmolality. Longstanding cases of PU/PD may be complicated by renal medullary washout, … Medullary washout. Longstanding cases of PU/PD may be complicated by renal medullary washout, … Results: Of the 36 dogs with adrenal masses, cortical adenocarcinoma was most commonly diagnosed (16 dogs), followed by pheochromocytoma (13 dogs), and cortical adenoma (7 dogs).