Overview of Bloody Urine in Cats
Hematuria is the presence of red blood cells in the cat’s urine. It may be gross (visible to the naked eye) or microscopic.
Below is an overview of causes, diagnosis and treatment of bloody urine in cats followed by detailed in-depth information about this condition.
Possible causes of hematuria in cats include:
Bacterial infections of the urinary and genital tracts such as cystitis (bladder infection) or vaginitis
Cancer of the urinary or genital tracts
Calculi (stones) in the urinary tract
Congenital urinary tract abnormalities (those present at birth)
Rare parasites of the urinary tract
Clotting (bleeding) disorders including anti-coagulant rat poison (warfarin)
Medication-induced (e.g., cystitis caused by cyclophosphamide, a drug used to treat some types of cancer and immune-mediated diseases)
Benign idiopathic (“of unknown cause”) hematuria originating from the kidney
The effect of hematuria on the pet may range from no obvious effect to severe. Severe bleeding into the urinary tract may cause the cat to become anemic and may cause weakness or collapse.
Other symptoms that commonly accompany hematuria include:
Painful or difficult urination
Straining to urinate
Frequent passage of small amounts of urine
You should have your pet examined by your veterinarian if you observe hematuria or any of these other symptoms.
Diagnosis of Hematuria in Cats
Your veterinarian may recommend one or more of the following tests to evaluate your pet for hematuria:
Urine culture and sensitivity
Microscopic examination of vaginal smears
Complete blood count
Serum biochemistry tests
Clotting profile including platelet count
Plain abdominal X-rays
Contrast dye X-ray studies
Abdominal ultrasound examination
Treatment of Hematuria in Cats
Treatment depends upon the diagnosis. Your veterinarian may prescribe one or more of the following treatments for your cat:
Antibiotics for possible bacterial infection of the urinary or genital tracts
Dietary changes for certain types of calculi (stones)
Fluid therapy for dehydration
Vitamin K for consumption of anti-coagulant rat poison
The presence of blood in the urine (hematuria) is abnormal. If you observe hematuria, you should take your cat to your veterinarian for evaluation.
Observe your cat closely for any of the associated clinical signs such as pain or straining when urinating. If possible, obtain a voided (free-catch) urine sample from your pet and take it with you when you visit your veterinarian.
Administer all prescribed medications as directed by your veterinarian. Promptly bring any unexpected changes in your pet’s condition to the attention of your veterinarian. Evaluate your pet’s environment for the presence of possible toxins. (specifically, anti-coagulant rat poison).
In-depth Information on Hematuria (Blood in Urine) in Cats
Hematuria (blood in the urine) can be caused by several different disorders. The most common causes of hematuria are:
Bacterial urinary tract infection
Stones in the urinary tract especially in the bladder or urethra
Cancer of the urogenital (urinary or reproductive) tract, especially cancer of the bladder or urethra
Urogenital (urinary or reproductive) disorders such as uterine infection and vaginitis
Congenital abnormalities (those present at birth) of the urinary tract, most often an outpouching of the bladder called a urachus
Less common causes of hematuria include:
Clotting abnormalities caused by low platelet count (called thrombocytopenia), warfarin (rat poison) ingestion, and disseminated intravascular coagulation (a systemic clotting problem seen in seriously ill animals)
Parasites of the urinary tract (the kidney worm Diotophyma renale and the bladder worm Capillaria plica)
Trauma to the urinary tract (kidneys or bladder)
Some drugs such as cyclophosphamide (a drug used to treat cancer and immune disorders) can cause hematuria by inducing a sterile (non-infectious) hemorrhagic cystitis
Bleeding from the kidney of unknown cause (referred to as “benign renal hematuria”) is rare but when present can cause hematuria that is severe enough to lead to anemia
The following tests may be needed to diagnose the cause of hematuria:
Urinalysis to evaluate for white blood cells, red blood cells, crystals and bacteria.
Bacterial culture of urine to identify urinary tract infection and determine the best antibiotic to use to treat the infection.
A complete blood count to evaluate for systemic infection, anemia, or low platelet count (thromobocytopenia).
Serum biochemistry tests to evaluate kidney and liver function and to identify electrolyte and acid base disturbances.
A panel of clotting tests to assess whether the pet’s blood can clot normally.
Vaginal cytology in intact female cats that may have vaginitis.
Abdominal X-rays to evaluate bladder and kidney size and identify stones dense enough to be visible on plain X-rays.
Abdominal ultrasound to evaluate the urinary tract for stones, tumors, obstruction to flow or evidence of infection in the kidneys themselves (pyelonephritis). Ultrasound often is recommended when other diagnostic procedures have been inconclusive. Completion of an ultrasound examination may necessitate referral to a specialty hospital.
A contrast dye study to evaluate the urinary tract for stones, tumors or obstruction. A contrast study of the upper urinary tract (kidneys and ureters) is called an excretory urogram or intravenous pyelogram. This study can identify obstruction of the upper urinary tract and signs of kidney infection (dilated kidney pelvis). A contrast study of the lower urinary tract (bladder and urethra) is called a cystourethrogram. This study can help identify bladder tumors or congenital abnormalities such as an outpouching of the bladder wall (urachal diverticulum). These tests may be recommended if other diagnostic tests were inconclusive.
Cystoscopy in female cats allows evaluation of the vagina, urethra, and bladder by introducing a rigid scope urethra and bladder. This technique allows the veterinarian to visualize congenital abnormalities of the urogential tract, tumors, stones and other abnormalities. It also allows for small biopsy samples to be obtained through the scope without the need for major abdominal surgery. Cystoscopy usually is done after other diagnostic procedures have been inconclusive. It necessitates general anesthesia and referral to a specialist.
Treatment of hematuria depends on the underlying cause. Treatments for the common causes of hematuria are as follows:
Antibiotics are used to treat bacterial urinary tract infection. Ideally, the antibiotic should be chosen based on bacterial sensitivity testing to identify the antibiotic most effective for the particular type of bacteria causing the infection. However your veterinarian may make an educated guess about which antibiotic to use based on knowledge of the types of bacteria that commonly cause urinary tract infection and the ability of several antibiotics to be secreted into urine by the kidney tubules. Treatment generally is recommended for 2 to 3 weeks.
Fluid therapy may be recommended for pets that are dehydrated. It also may be recommended to increase urine output (establish a diuresis).
Dietary changes may be recommended if stones are present in the urinary tract or if kidney failure is present.
Vitamin K is the treatment of choice for hematuria secondary to warfarin (rat poison) ingestion.
Surgical intervention may be necessary for the removal of stones or tumors in the urinary tract or to correct congenital abnormalities. Surgery also may be necessary to determine wheter bleeding is coming from the left or right kidney in rare cases of “benign renal hematuria.”
Chemotherapy may benefit in some animals with cancer of the urinary tract.