by Barry B. Burtis D.V.M.
Prostatic Diseases of the Dog
Disorders of the prostate occur primarily in un-neutered adult male dogs. Sometimes a routine physical examination by a veterinarian will detect early signs of prostatic disease. In other cases, a dog may be taken to an animal hospital with complaints suggestive of a gastrointestinal or urinary tract problem. A thorough evaluation may be necessary to localize the problem to the prostate and to identify the specific disease.
The most common signs shown by a dog with prostate disease are blood in the urine, a discharge from the penis, a loss of appetite and lethargy. Often an owner reports they have noticed the dog straining, in apparent effort to pass either urine or stools. Bacterial infections of the prostate often cause secondary urinary tract infections. Hence, clinical signs of difficult urination, passage of blood coloured urine, or increased frequency and urgency of urination may be noticed. Occasionally an owner may notice a discharge of pus or bleeding from the penis that is unassociated with urination. If the disease process is more severe or associated with pain, the patient may exhibit rear leg weakness, stiffness or lameness. In such cases, loss of appetite, fever, vomiting, weight loss and lethargy are more likely to occur.
Diagnosis of the disorder will begin with palpation of the prostate during digital rectal examination. Blood and urine tests are performed if prostate problems are suspected to identify infection. X-rays can be used to evaluate the size, location and shape of the prostate. Ultrasound examination allows another way of imaging the prostate and can be used to guide prostatic aspiration or needle biopsy. Collection of prostatic fluids, via fine needle aspiration or prostatic wash, will allow the samples to be cultured and/or have cellular examinations performed on them.
The most common types of prostate disease encountered in our pet dogs are, benign prostatic hyperplasia, prostatitis, prostatic cysts and cancer of the prostate.
Benign prostatic hyperplasia is an aging change in sexually intact dogs. By the age of 9 years, nearly 95% of dogs are affected. Most dogs with this condition will show no clinical signs as a result of its presence, although some can be affected as discussed earlier. Palpation of an enlarged prostate is often the most reliable and only required diagnostic measure. Castration is the treatment of choice. The prostate decreases by 70% within 9 weeks of such surgery.
Prostatitis as a result bacterial infections may be acute or chronic. These bacteria usually migrate from outside the body via the urethra, the tube that takes urine away from the bladder. Sometimes abscesses in the prostate form as a result of these infections. Once again, dogs with this problem will usually have an enlarged prostate that is painful on palpation. They are likely to be showing a number of the clinical signs mentioned above and some of the diagnostic measures discussed will be required. These tests will be used to direct antibiotic therapy which is the most important part of initial therapy. Castration is recommended to decrease the size of the prostate, increase the speed of resolution of infection and minimize potential recurrence. Castration would not be done until antibiotic therapy has been started.
When prostatic cysts occur, surgery is usually necessary to drain or remove them. Again castration will usually be part of the treatment plan. This will eliminate any hormonal effects on the disease as well as reduce the size of the prostate gland.
Several types of prostate cancer can affect dogs, but the incidence is quite low. The success rate for the treatment of this type of prostatic disease will vary depending on the type of cancer and the stage at which the disease is identified.
If you have questions about the prostate gland and its affect on your dog's health, ask your veterinarian.