Blood in the urine (hematuria) of male dogs: Bladder, Urethra, Prostate

Causes of hematuria from the lower portion of the urinary tract:

After examining your pet and obtaining the tests that will help make a diagnosis, which were listed in the blog yesterday, your veterinarian will determine whether the blood in the urine was from the kidneys or from lower in the excretory system—bladder, prostate or urethra. One way this is done is to compare urine from the bladder obtained by cystocentesis with urine that was voided and passed through the bladder, prostatic section of the urethra, and the urethra. Cystocentesis involves putting a needle directly into the bladder and drawing urine out. If there is no blood in the cystocentesis sample, but there is blood in the voided sample, the problem is not the bladder, but the urethra or prostate.

To further isolate the cause, your veterinarian determines whether the prostate feels normal, enlarged, smooth, or irregular. Not all prostate problems are palpable, but ultrasound helps reveal prostatic abnormalities that veterinarians cannot find with their fingers. Among prostatic problems are benign hyperplasia, infections, and tumors.

If the prostate is free of problems, the veterinarian examines the urethra for crystals, infections, or tumors. Male dogs don’t have urethral problems that overweight females have. With overweight females, deep folds of skin surround the vulva, and bacteria become trapped within the folds. These bacteria provide a constant supply of infectious microbes that lead to urethral and bladder problems. In addition to having increased bacteria due to obesity, female dogs also have increased urethral bacteria if they scoot on their bottoms because they have itchy or sore anal area. Anal sac inflammation, for example, often causes scooting. The scooting rubs bacteria into the perineal area and abrades the skin. This increases the likelihood of urethral infections. Males may have anal sac inflammation and may scoot, but the male urethra is not near the anus so scooting and anal sac inflammation doesn’t cause bacterial contamination.

Males do have a prepuce, which is the fold of skin that holds the penis. infectious bacteria, including Ureaplasma, can hang out in the prepuce, travel up the urethra and into bladder, causing infection and bleeding. Some dogs have pus dripping from the prepuce and urethra. Others have no obvious signs of infection, but actually have infections. In addition to all infections not being obvious, some bacteria are extremely difficult to find when urine is cultured. For example, Ureaplasma is difficult to culture, and veterinarians ask the laboratory to do special tests when Ureaplasma is suspected.

What other problems might cause bleeding that originates in the bladder or urethra? Stones and crystals. Some of these are visible on X-rays and some are not. Some will be palpable and others will not be. The bladder wall may feel thickened when palpated suggesting chronic irrigation that leads to bleeding. Some bladders bleed because the normal mucus lining is not made. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as Rimadyl, decrease the production of mucus and veterinarians will consider the effect of all medications pets take when diagnosing the cause of hematuria.

Today, we’ve covered possible causes of blood in the urine (hematuria) that originate in the lower portion of the urinary tract. Tomorrow the blog will look at causes of hematuria from higher in the tract, such as the kidneys and ureters.

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