The prostate is a bi-lobed accessory gland of the urogenital tract that
surrounds the neck of the urinary bladder. The structure is well developed in
intact male dogs, but not as much so in cats. In health, the prostate
contributes to the formation of seminal fluid, supplying the portion of
ejaculate that follows the fraction containing the sperm.
Neutering dogs while
they are puppies or young adults will largely prevent prostatic hyperplasia and
infection.
Doberman pinschers appear to be at high risk for problems of
the prostate. The gland typically enlarges over time under the influence of
testosterone and other hormones. Glandular thickening initiates the process in
the first two years of life, causing progressive hyperplasia or
over-development of the gland.
Benign prostatic hyperplasia or BPH is a common prostatic
disorder, and common signs of it include the appearance of blood in the urine
or ejaculate, discharge dripping from the penis or prepuce, and difficulty with
defecation. The prostatic enlargement is typically symmetric, affecting both
lobes. The prostate will feel larger on abdominal palpation or with palpation
through the rectum, but the examination should not cause pain.
BPH typically progresses to a more complex problem over time,
with areas of cellular collapse, fibrous thickening, and the formation of
cystic areas. These fluid-filled cystic areas may be large or small, and can
potentially double the size of the gland. Changes are often asymmetric,
conferring an irregular contour to the gland that the veterinarian likely will
recognize while palpating the prostate.
The enlarging prostate can cause the colon to be displaced, and
this may interfere with normal defecation. Dogs with significant prostatic
enlargement are often constipated and strain excessively to defecate. Less
commonly, BPH interferes with normal voiding of urine by compressing the
urethra.
Because of BPH, bacteria may more readily infect the gland.
These bacteria usually migrate into the prostate from the lower urinary tract,
and frequently infect the urinary bladder, as well. Inflammation of the
prostate associated with bacterial infection may be acute or chronic. It is
very common for prostatic infection or abscess to liberate bacteria into the
blood stream. Whole body infection with circulating toxins and shock is a
possible complication of bacterial prostatitis or abscessation, and this
condition may be fatal. Large abscesses or prostatic cysts may require
immediate surgical drainage and intensive medical management.
Dogs with acute prostatitis will often have fever and signs of
systemic illness, such as loss of appetite, malaise and depression, as well as
localized signs of prostatic inflammation that include swelling, pain and
urinary discharge. The prostate is likely to be enlarged, and is frequently
irregularly shaped and painful when touched or palpated. Affected dogs may have
an awkward gait and hindlimb swelling associated with blockage of lymphatic
vessels. Defecation and urination habits may be changed.
If the infection persists chronically, the dog may show
intermittent signs of illness or vague and nonspecific signs. However, dogs
with chronic prostatitis may behave normally except for a reluctance to breed.
Or they may display infertility. Incomplete antibiotic treatment is one reason
for the development of chronic inflammatory changes in the prostate.
Castration is routinely advised along with antibiotic treatment
of acute or chronic bacterial prostatitis to immediately reduce
testosterone’s effects on the prostate. Medical strategies to alter
hormonal stimulation without reducing fertility may be elected for patients
with acute or chronic prostatitis. For successful management of prostatitis,
surgical castration is preferred if there is no intent to spare fertility.
Neutering of puppies or young adult dogs will largely prevent prostatic
hyperplasia and infection: the gland atrophies rapidly when the source of
circulating testosterone is removed.
Castration does not, however, protect against prostatic cancer,
which occurs with similar frequency in castrated and intact male dogs. If a dog
patient appears to have meaningful prostatic disease, based on clinical signs
and changes visible on x-rays and ultrasound, and he is known to be castrated,
and free of hormonal supplementation, then prostatic cancer is the most likely
diagnosis. Prostatic adenocarcinoma is a malignancy that arises from the
secretory cells of the prostate. This cancer is considered an aggressive
malignancy that tends to spread rapidly to the regional lymph nodes or bones of
the pelvis as it metastasizes. By the time of diagnosis of PAC, most dogs have
advanced disease for which there is no consistently successful treatment.
Castration may improve lower gastrointestinal or urinary signs
if BPH or prostatic inflammation are also present, but generally, a tumor
won’t be influenced by alterations in hormone levels. Surgical specialists
may offer prostatectomy or surgical removal of the cancerous tissue, concurrent
with urinary redirection. Such radical surgeries are rarely encouraged because
they are unlikely to be curative and they may not improve the pet’s
quality of life. Also most patients are incontinent after surgical removal of
the prostate.
Local radiation therapy or urinary diversion may aid dogs that
have obstruction to urine outflow associated with the mechanical effects of
PAC. Constipation and obstipation may improve with the use of stool softeners
and dietary manipulation. Any secondary bacterial infection should be treated
with antibiotics. Regrettably, even with aggressive chemotherapy, dogs with
prostatic adenocarcinoma rarely survive more than three to four months beyond
diagnosis.
Diagnosis of prostatic disease and discrimination between
benign processes, prostatic infection, and cancer, may require a series of
diagnostic tests. A complete blood count and urinalysis and x-rays may be the
most helpful screening tests. Ultrasounds of the prostate and specialized dye
studies offer useful information about the architecture of the prostate that
may help to predict the severity of the disease. Bacterial cultures and
analysis of prostatic fluid collected by ejaculation or prostatic wash
procedures may reveal specifically the presence of bacteria and inflammatory
cells to verify primary or secondary infection. Occasionally, tumor cells are
recovered in this way. Urine cultures are frequently collected as well.
Special tests for antibodies to Brucella canis, a
bacteria that is transmitted venereally, are advised for dogs that have been
sexually active. Ultrasound guided sampling of prostatic tissue with a fine
needle or needle biopsy device is often employed if cancer is suspected. Rarely
will open surgery be required to verify a diagnosis of malignant cancer.
Currently, there are no simple blood tests in use to establish the presence of
prostatic malignancy in dogs, although there are such tests available for
humans.
Dogs with significant
prostatic enlargement are often constipated and strain excessively to
defecate.
Simple solid or cystic enlargement in an intact male dog
that is otherwise healthy is likely due to BPH; castration may be elected in
lieu of diagnostics, with monitoring for prompt regression of the glandular
enlargement. If, however, bacterial infection is considered likely, then a more
aggressive approach is likely to be suggested to avoid the possibility of a
life-threatening problem. Delaying the diagnosis of cancer is unlikely to
change the outcome for the pet, so a more conservative approach may be
reasonable.
Prevention of most prostatic diseases can be accomplished by neutering your
pet while he’s still a puppy. If signs of prostatic disease are
recognized, diagnostic testing is likely to be required to establish a
treatment course that is most appropriate. Prostatic infection may be fatal,
and should be considered for the prostrate, intact male dog with fever,
abdominal pain and an enlarged or painful prostate. Fortunately, though, this
type of cancer is relatively uncommon.
