A Yorkshire Terrier bitch presented hematemesis, abdominal distention, poliuria, and polidipsia. After clinical examination, it was established a clinical suspect of nephropathy. The complementary exams showed normochromic and normocytic anemia and serum concentrations of ureia (306mg/dl) and creatinine (3.6mg/dl) above the references values. At two-dimensional ultrasound hipoechoic and anechoic cystic areas were observed, as well as hiperechogenic renal pattern and corticomedullary ratio loss. At necropsy, the medullary region presented many small cysts in a fibrous connective tissue. Cortical tubulointesticial lesion was responsible to the resulting renal failure. It was established a tubulointersticial nephritis diagnosis.
dog; cystic medullary renal disease; nephrology