Canine Benign Prostatic Hypertrophy
Benign Prostatic Hypertrophy (BPH) occurs in only two species: man and dog.
Let’s break down the term. Benign means that there is no cancer involved. Prostatic is an adjective referring to the prostate. Hypertrophy means “to enlarge.”
The primary purpose of the prostate is to house glandular structures to produce seminal fluid to carry sperm during ejaculation.
In the two species the disease has similarities. Age is a one common factor. While BPH has been reported in dogs as young as 2½ years, we rarely see the clinical presentation that young. Another shared trait is the necessity of the presence of testes (testicles). Some researchers believe that an imbalance between testosterone and estrogen is a factor in the condition in dogs and in people. Neutered male dogs and men who have undergone castration surgery do not suffer from BPH, as the source of testosterone and its metabolites is removed.
Contrasting signs in the species include the new shape of a BPH prostate. Dogs’ prostates tend to enlarge uniformly and remain smooth when palpated from the outside. Men’s prostates, on the other hand, become nodular, or lumpy. On a microscopic level the differences are dramatic.
After a dog’s prostate begins to hypertrophy, the glands inside enlarge and can become cystic, meaning that pockets of fluid may develop. As this fluid is nutrient-rich, bacteria may grow in it if they enter from the bloodstream, the urinary tract or from the testes and spermatic cords. Even uninfected cysts may produce such swelling and enlargement of the prostate that normal urination is impeded. Pressure applied to the urethra as it passes through the prostate can reduce the diameter of the urinary passageway dramatically.
Just as the brain and spinal cord possess a blood-brain barrier, the prostate has a blood-prostate barrier. Some pharmaceuticals, such as antibiotics, thus find it difficult to enter the prostate. Clearing a prostatic infection can be a challenge requiring bacterial culture and sensitivity, long periods of antibiotic therapy and expensive antibiotics that have properties that allow them to cross the blood-prostate barrier to fight the infection.
Fortunately, uncomplicated BPH is easily treated. Surgical neutering, or castration, of a dog reduces the prostate’s size by up to 80%. If there are no complicating factors, such as cancer or infection, that’s the end of the story. The prostate gland undergoes involution, essentially shrinking, and is unlikely to cause problems, even in older pets.
I will never forget an old Collie I once had to euthanize. He was the best friend of an elderly Navy veteran who lived alone. We tried everything, but the poor dog had such prostate swelling that he could not urinate. Even with attempts to control his urinary tract infection and repeated catheterization, he could not regain enough bladder muscle tone to empty his urinary bladder on his own.
BPH is a completely preventible disease. Having your male dog neutered when he is young, or at least before prostatic enlargement causes urine retention, will prevent him having to suffer as that Collie did.
See you tomorrow, Dr. Randolph.