I recently noticed blood in my dog's urine. The veterinarian put her on antibiotics, but they don't seem to be helping. What could cause this?
Bloody urine can be associated with local problems of the genitourinary tract or with a systemic bleeding tendency. In the absence of other signs of systemic bleeding or hemorrhage, a local problem is more likely.
Hematuria (blood in the urine) is commonly associated with urinary tract infection (UTI), especially if the infection is localized to the lower urinary tract or bladder. Patients with bladder problems are likely to have urgency, straining, and frequent urination. They may experience temporary incontinence, or loss of control, because of irritation to the sphincter. Generally, antibiotics are prescribed for urinary tract infections diagnosed on clinical grounds. Failure of these signs to respond to an antibiotic does not exclude the possibility of urinary infection. It is possible for the bacteria to be resistant to a given antibiotic choice. In such cases, securing a bacterial culture and susceptibility helps to verify or to rule out infection and to determine the best antibiotic choices.
UTI is frequently associated with the presence of bladder stones, which may also contribute to hematuria. Bladder stones can form over a few weeks or months or years. Most dog patients with struvite stones, the most common type of bladder stones associated with infection, develop the condition by middle age. Other types of stones, which are metabolic in origin or breed related, might form at a very early age. Many stones will appear on survey x-rays.
It would seem then that your dog might still have a resistant urinary tract infection with or without bladder or kidney stones.
Older dog patients, with signs of hematuria and straining while urinating, that fail to respond completely to antibiotics may have a bladder tumor that has become secondarily infected. Such signs typically progress over weeks to months. Embryonic tumors have been documented in young dogs, but these are genuinely rare.
If patients have blood in the urine without signs of straining or urgency, an upper urinary source is more likely. Dogs seem to show few signs of pain associated with the presence of kidney stones. The appearance of blood in the urine in these cases may support a diagnosis of kidney stone(s) or kidney infection. Radiographs are indicated if stones are suspected.
Less commonly we see hematuria as a vascular problem of the kidney. Essential renal hematuria is an uncommon diagnosis, which is associated with mild to severe bleeding from one or both kidneys. Some patients experience life-threatening anemia or chronic anemia and iron deficiency as a result. Obstruction of the bladder or urethra with blood clots can occur, although this is more common in male dogs.
Renal hematuria is sought as a possible cause only when other more common problems, including bleeding and clotting problems, have been ruled out. Selective ureteral catheterization and tissue sampling are needed for verification, either through surgery or cystoscopy.
Most bleeding disorders can be investigated by a combination of physical exam and laboratory testing. Common problems with clotting that could present as hematuria include low platelets (thrombocytopenia) and exposure to Vitamin K antagonist rodenticides (warfarin based) compounds.
If your dog's problems persist, you may wish to speak with your veterinarian about referral to a veterinary specialist for abdominal ultrasound, contrast study of the bladder or kidneys or other diagnostic testing of her bloody urine.
09/29/00
