Massive hematuria of nontraumatic renal origin in dogs.

Massive hematuria of renal origin was diagnosed in 4 dogs. In all dogs, blood and blood clots were clearly visible in the urine. Serum urea nitrogen and urine concentrating ability were normal. All dogs were anemic, and results of coagulation and platelet function tests were within normal limits. Excretory urography indicated hydroureter and hydronephrosis in all dogs, with filling defects in the bladder attributable to large blood clots in 2 dogs. Cystotomy and catheterization of the ureters enabled identification of one kidney as the source of bleeding in 3 dogs. Unilateral nephrectomy and ureterectomy resolved their hematuria. The results of histologic examination were normal in 2 dogs. The 3rd dog had evidence of pyelitis. Cystoscopy of the 4th dog did not reveal hematuria from either ureter. The dog was not operated on and it continued to have intermittent hematuria.