Blood in dog urine, also known as hematuria, can be a bit startling and is certainly cause for concern, but it is something you will likely observe at some point as a dog owner. Fortunately, the most common causes of bloody urine are fairly easy to resolve. When you observe bloody urine, take note if your dog is urinating a normal amount, has a steady stream versus spurts, how often they need to urinate, if they are straining when they urinate, and if the bloody urine is seen throughout the entire urine stream or only at the beginning or the end. Also consider whether it’s possible your dog suffered trauma recently, such as being accidentally kicked or stepped on, or if your dog overexerted himself. Your observations of your dog’s eliminations will help your veterinarian more quickly arrive at a diagnosis. Read on to learn about the most common causes of bloody urine in dogs.
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Blood in Dog Urine due to Infection
Probably the most common reason to see blood in your dog’s urine is due to an infection of the urinary tract, whether it be the kidney, bladder, or urethra. Signs of a urinary tract infection (UTI) include blood in the urine (red, pink, or brown color), straining to urinate, urinating small amounts with excessive frequency, apparent loss of housetraining, strong urine odor, and possibly lethargy and discomfort. Females are much more likely to get urinary tract infections due to the relatively short distance between the outside world and their bladders, making it relatively easy for bacteria to work their way up into the urinary tract. Congenital defects in the anatomy of the female dog’s external genitalia can also increase the likelihood of UTIs.
Your veterinarian will ask you some questions about your dog’s recent urinary habits that can help them determine which part of the urinary tract is affected. Your veterinarian may also ask you to bring in a sample of your dog’s urine. You can use a clean, disposable container to catch the urine and store it in the refrigerator for up to 12 hours before your dog’s appointment, though the fresher the sample, the better. The urine sample will be analyzed by a test called a urinalysis, which can usually be done in-house. This test measures red and white blood cell levels, pH, specific gravity, and the amount of glucose and protein present in the urine. A sediment analysis should be performed as well; this test involves looking at the solid parts of the urine after it has been spun down in a centrifuge. Any red blood cells, white blood cells, or bacteria can be then be looked for under a microscope.
If your dog has been having frequent urinary tract infections, or if the initial antibiotic treatment did not seem to help, an additional test called a urine culture and sensitivity should be performed. This involves obtaining a sterile urine sample via a process called cystocentesis, where a sterile needle is inserted into the bladder through the abdomen and a small sample of urine is collected in a syringe. This process ensures that the sample obtained isn’t contaminated with any bacteria hanging out around the external genitalia. The urine is then sent to the laboratory where they will grow any bacteria present in the sample and then test that bacteria against various antibiotics. In a few days, your veterinarian will receive a report as to whether any bacteria grew, and if so, which antibiotics would be most effective in treating the infection.
Treatment of urinary tract infections involves 10-14 days of oral antibiotics. Your veterinarian will usually have your dog come back for a recheck a couple of days after finishing the antibiotics to make certain the infection is gone; a repeat urinalysis or urine culture may be performed at that time.
UTIs are generally rare in most dogs and preventative steps generally do not need to be taken. However, in some dogs, particularly females, UTIs can be fairly frequent. Your veterinarian may recommend a cranberry-based urinary tract health supplement such as [Nutramax’s Crananidin], which changes the pH of the urine and may make the urine a less hospitable place for bacteria to grow. As mentioned above, some female dogs are born with a malformation of the external genitalia which traps bacteria near the urethra, making UTIs much more likely. In this case, your veterinarian may recommend using a cleansing wipe around the vulva after your dog urinates. A more permanent fix is a surgery called vulvoplasty which corrects the malformation and should decrease the frequency of urinary tract infections.
Blood in Dog Urine – Bladder stones (urolithiasis) or crystals (crystalluria)
Bladder stones or crystals can cause blood in the urine from the irritation generated by the stones or crystals knocking against the inside of the bladder wall. The most common symptoms of bladder stones or crystals are blood in the urine and straining to urinate. Your dog may also be less active or lethargic due to the pain associated with the bladder stones or crystals.
Bladder stones or crystals are formed from minerals that are normally found in your dog’s urine, such as magnesium ammonium phosphate (struvite), calcium oxalate, citrate, or ammonium urate. The amount of minerals present in the urine can be affected by diet, previous disease such as a bladder infection, or abnormal metabolism. Once the amount of a particular mineral reaches a certain saturation point, the minerals precipitate out of the urine and form a crystal. Some crystals will never develop beyond this point, but other crystals will knock into the bladder wall, causing a protective mucus to form on the bladder wall, which then sticks to the crystals, picking up more crystals and more mucus and so on, eventually forming a stone.
Crystals are detected via microscopic analysis of a urine sample whereas bladder stones can be detected by either radiography or ultrasound depending on the type of stone. (Some stones are not visible on radiographs but may be detected with ultrasound.) The type of crystal present can be determined by microscopic examination of the crystals; each type has a unique shape. The type of bladder stone might be able to be determined by its shape or whether it is visible on radiographs, but it’s usually necessary for the bladder stone(s) to be sent to an outside lab for analysis of its composition.
Treatment of the crystals or bladder stones will be determined by the type of crystal or stone, the severity of the issue, and the risk of a stone lodging in the urethra and preventing the bladder from being emptied.
If struvite stones are relatively small and there is little concern that they will cause a urinary tract obstruction, feeding a specialized diet to dissolve the stones may be recommended. These prescription diets will dissolve struvite stones that are already present in the bladder and prevent new ones from forming. Dissolution of the stones can take anywhere from two weeks to three months. As the stones dissolve, they will release bacteria that have been trapped in the layers of the stone, potentially causing a urinary tract infection, so your veterinarian will likely prescribe antibiotics during the dissolution process. Your dog’s progress will be monitored every four to six weeks with repeat radiographs and urinalyses.
Other possible non-surgical treatments for very small stones of any type include a technique called urohydropropulsion. While your dog is under heavy sedation or general anesthesia, a special urinary catheter is passed into the bladder and the stones are flushed out. Stones could also possibly be removed using a cystoscope, which is an instrument with a camera and light source at the end; the cystoscope is passed into the bladder similar to a catheter. Tiny forceps are passed through the cystoscope, and using the camera for visualization, the veterinarian can grab the stones and remove them. Some specialty veterinary clinics may also offer ultrasonic dissolution, which is using high frequency ultrasound waves to break up the stones which can then be flushed out of the bladder.
For larger, multiple stones that are unlikely to respond to a dissolution diet or are likely to cause an obstruction, surgery to remove the stones will be recommended. While surgery is not to be taken lightly, it has the benefit of resolving the situation quickly, and once your dog has recovered from the procedure, they will no longer be in discomfort from the stones.
Dogs that develop struvite bladder stones will likely need to be on a specialized diet for the rest of their lives in order to help prevent the formation of more bladder stones. The recommended diet will be lower in phosphorus, magnesium, and protein, and also promote a more acidic urine pH. Since urinary tract infections (UTIs) are a major risk factor in developing these types of stones, dogs with signs of a UTI such as straining to urinate, frequent urination, blood in the urine, or urinating in unusual places should be checked out by a veterinarian as soon as possible.
Recommendations for dogs with crystals or stones other than struvite include an increase of water intake in order to keep the urine dilute, and may also include a specialized diet to help prevent formation of crystals and stones. If a specialized diet is recommended for your dog, it is very important to feed that diet exclusively, which means no table scraps or treats unless your veterinarian has given the okay. Feeding anything other than the recommended diet may undermine what the diet is formulated to do – prevent the formation of new bladder stones.
Blood in Dog Urine – Neoplasia
Cancers of the urinary tract are relatively rare, accounting for less than 2% of all canine cancers. The most common of the urinary tract cancers is transitional cell carcinoma (TCC). There does appear to be a genetic predisposition to TCC; Scottish terriers, Shetland sheepdogs, beagles, West Highland terriers, and wire hair fox terriers are more likely to develop TCC compared to other breeds. A study comparing Scottish terriers living where lawns had been treated with herbicides versus those who were not exposed to lawn chemicals showed that those dogs exposed to lawn chemicals were seven times more likely to develop TCC. In humans, smoking is the most common cause of TCC, but it is unknown if second-hand smoke is a risk factor for dogs to develop TCC.
The most common signs of TCC are bloody urine and straining to urinate, the same symptoms as urinary tract infections. In fact, the cancer may respond briefly to antibiotics and pain medications, so it would be easy to assume that the symptoms were being caused by an infection. Masses might be identified on radiographs or ultrasound, but those masses are not necessarily cancerous. Until recently, the only way to definitively diagnose TCC was through a biopsy of the tissue, which would be done via either surgery or by cystoscopy (passing a fiberoptic scope through the urethra and collecting a sample through the scope). Just a few years ago, a urine test was developed by Antech Laboratories to detect a genetic mutation found in TCC (and prostatic carcinoma). This screening test, called the Cadet BRAF assay, has no false positives (meaning a positive result is diagnostic for TCC) and only 5% false negatives. Thus this test is a much less invasive way to get a diagnosis compared to tissue biopsy.
Transitional cell carcinoma does readily metastasize (spread to other organs), so when TCC is diagnosed, veterinarians will recommend thoracic radiographs to screen for lung tumors, and abdominal ultrasound to look for cancer spread within the abdomen. The abdominal ultrasound can also be used to precisely locate the tumor within the bladder; a CT scan may also be recommended for the same reason.
Surgical excision of the mass is usually recommended for TCC when it has not spread beyond the bladder. However, the location of the mass within the bladder may make it impossible to remove without damaging or compromising bladder function. Radiation therapy may also be an option, but given that the bladder changes in size and location within the abdomen, it’s difficult to effectively target the tumor. Radiation can also cause undesirable side effects such as creating a scarred and shrunken bladder and irritation to the organs surrounding the bladder.
The most common treatment of TCC is a combination of an NSAID called piroxicam and an IV chemotherapy drug called mitoxantrone. Average survival times using this protocol are in the 250-300 day range. In comparison, surgery alone has an average survival time of 109 days, while piroxicam alone has a survival time of 195 days. Purdue University recently completed a study combining piroxicam with an IV chemotherapy drug called vinblastine wherein the average survival time of using both drugs in combination resulted in an average survival time of 299 days. However, when vinblastine was used first and then piroxicam started when vinblastine stopped being effective, the average survival time was 531 days.
As far as preventing TCC, while the use of lawn chemicals has not yet been linked to TCC in breeds of dogs other than the Scottish terrier, it would be reasonable to avoid exposing your dog to lawn chemicals wherever and whenever possible. Second hand smoke has not yet been shown to increase the risk of TCC, but has been shown to cause other disease in dogs, so limiting your dog’s exposure to cigarette smoke may also be helpful. In high risk breeds, consider the use of the Cadet BRAF assay to screen for TCC about every four to six months once your dog reaches six years of age. While it won’t prevent the disease, it will allow you to start treatment earlier in the disease process which may translate to a longer survival time.
Blood in Dog Urine – Trauma
Trauma to the urinary tract can cause blood in the urine. Most of the causes are iatrogenic, meaning as a consequence of a medical procedure, such as urinary catheterization, cystocentesis (using a needle to collect a urine sample directly from the bladder), or kidney biopsy. Other types of trauma that could cause blood in the urine include being hit by a car or kicked by a horse.
Iatrogenic causes of bloody urine will usually resolve on their own within 24 hours as the irritation subsides. For bloody urine due to blunt trauma, your veterinarian will look for the extent of damage to the internal organs by performing radiographs and/or abdominal ultrasound as well as blood work such as a complete blood count (CBC) and chemistry panel. Treatment will depend on the extent of the damage and may range from emergency surgery to stop internal bleeding to hospitalization for monitoring with IV fluids to monitoring at home with exercise restrictions and pain medications.
Blood in Dog Urine – Rhabdomyolysis
Rhabdomyolysis is the breakdown of muscle tissue that causes the release of muscle fiber contents (myoglobin) into the bloodstream. The myoglobin then damages the kidneys through a mechanism that is not completely understood. Rhabdomyolysis tends to occur in athletic dogs, such as greyhounds and sled dogs, especially when those dogs overexert themselves with relatively short but very intense exercise and the muscles do not receive an adequate supply of oxygen. However, it can occur in any dog whose muscles have been overworked or damaged in some way, such as after a prolonged seizure or after a major surgery such as a limb amputation. In addition to the reddish brown urine, signs include muscle pain and swelling, muscle wasting, apparent dehydration, weakness, disorientation, and nausea.
Because of the kidney damage that occurs with this condition, prompt medical treatment is essential for survival. Diagnosis can be confirmed with analysis of the urine. Treatment includes IV fluid therapy to flush the kidneys and correct dehydration and electrolyte imbalances, muscle relaxants, and pain medications. The prognosis for recovery is dependent on the severity of the condition and how quickly treatment is initiated.
While racing and in top condition, greyhounds generally do not run at top speed for more than 30-40 seconds, so adopters of retired racing greyhounds should not allow their dogs to exceed that duration and intensity of exercise, especially if they have not been kept in peak condition since retirement.
Idiopathic Renal Hematuria
This bleeding disorder originates in the kidney, but the exact cause is uncertain. Large breed dogs (Weimaraners, boxers, Labrador retrievers, etc.) of both sexes can be affected. Most are less than 5 years of age when the bloody urine is first noticed, and 30% are younger than one year of age. The main symptom of this condition is a profoundly bloody urine with no apparent discomfort. The urine is bloody from the start to finish of urination, and blood clots may occasionally be seen in the urine. The bleeding may occur for weeks to months, then disappear for months before appearing again.
Diagnostic tests include a CBC (complete blood count) to look for anemia (low red blood cell count) and a chemistry panel to look for abnormal kidney values. A urinalysis with culture and sensitivity is also performed to rule out bacterial infection. Tests for proper blood clotting will be performed to rule out any bleeding disorders. In female dogs, cystoscopy (fiberoptic scope passed through the urethra) can be used to observe the blood being emptied into the bladder from the ureter connected to the affected kidney(s). This test can be used to determine if one or both kidneys are affected.
Treatment depends upon the severity of the bleeding. If the bleeding is severe enough and chronic enough to cause severe anemia, and the bleeding can be documented to be originating from just one of the kidneys, then removal of that kidney (nephrectomy) may be recommended. Nephrectomy will resolve the anemia and bloody urine, but in some dogs, bleeding may then start in the remaining kidney, so the risks and benefits of nephrectomy should be carefully weighed before proceeding with the surgery. If there is a long period of time between episodes of bloody urine and the dog has only mild anemia or no anemia at all, then monitoring for developing or worsening anemia is likely to be preferable to nephrectomy.
Drug induced
A particular oral chemotherapy drug called cyclophosphamide (brand name: Cytoxan) may cause bloody urine as a side effect. The bloody urine is due to a sterile hemorrhagic cystitis caused by a particular metabolite (breakdown product of the drug) sitting in the bladder for too long after being filtered through the kidneys. Sterile hemorrhagic cystitis means that the bladder is irritated, but not due to an infection (the urine is still sterile).
Some veterinary oncologists also prescribe a diuretic drug called furosemide (brand name: Lasix) to be given along with the cyclophosphamide. The furosemide causes an increase in urination, which prevents the cyclophosphamide metabolite from sitting in the bladder long enough to cause the sterile cystitis. If a sterile cystitis occurs despite the use of a diuretic, your veterinary oncologist will likely switch chemotherapy agents, but the vast majority of dogs tolerate the drug when used sporadically as part of a lymphoma chemotherapy protocol. However, up to 30% of dogs receiving cyclophosphamide long-term (more than 2 months) develop cystitis. Your veterinary oncologist will discuss the pros and cons of the chemotherapy drugs available to treat your dog’s particular form of cancer.
Take away message for blood in dog urine
Bloody urine in dogs is a common problem encountered in veterinary medicine. While most causes are fairly straightforward and easily diagnosed and treated, others present more of a diagnostic and/or treatment challenge. Observations of your dog’s elimination habits can be very helpful in determining the appropriate diagnostic tests and reaching a diagnosis. Since bloody urine can be a sign of a serious condition, and at the very least, is usually quite uncomfortable for your dog, don’t delay in consulting a veterinarian when you see blood in your dog’s urine.