The Prostate Gland (Problems and Practical Help)

(Reprint permission received from Mr. Lanting)

My Uncle Max had to go to see the Roto Rooter man recently. Between us, that's our way to refer to his prostatectomy. Sometimes a painful experience is best handled with humor, which seems to dull some of the cutting edge. In the case of human prostate gland trouble, the bad news is that the subject is always burdened with worries about sex life afterwards, while the good news is that such worries are not entirely justified because of excellent surgical and medical techniques. In the case of dogs, there are no such psychological hangups, and the danger of cancer is not as high as the owner might imagine.

ANATOMY AND FUNCTION

What is the prostate? First of all -- PLEASE -- don't put an extra "r" in the word and pronounce it "prostrate", which means prone or lying flat. That is akin to confusing "spayed" (sexually neutered) with "spaded" (presumably dug up or hit on the head with a spade). The prostate is a male accessory sex gland, which means it plays a helpful role in the copulatory/breeding function. As shown in Figure 1, it is located at the next of the bladder, close to the rectum and pubic bone. If the bladder is full, it pulls the prostate further forward; if empty, the gland is pulled back toward the tail. In this location, therefore, it can best be palpated (examined by feeling with the fingers) by inserting a finger or two into the rectum and simultaneously pressing up into the abdomen with thumb and fingers of the other hand. In this way, it can be determined if there is any abnormal rigidity or swelling.

It has been said, and it makes sense, that the only function of the prostate is to supply sufficient fluid volume to "fill" the vagina and carry semen up the uterine horns to the ovaries, or at least get the sperm a good start on their way. The quantity of fluid produced by the testicles and associated tissues in the scrotum is too small to travel even to the end of the urethra ... not even far enough to leave the dog's body at ejaculation. There is also grounds for believing that prostatic fluid is necessary to make the sperm mobile.

Normally, sperm is produced continuously and at a very slow rate until the dog is bred or sexually excited. The epididymis (storage tubes on the testicle) and vas or ductus deferens steadily secrete a small amount of fluid to carry the sperm toward the prostate, helped along by muscle fiber contraction similar to the action of peristalsis which moves food and water through the intestinal tract.

Meanwhile, the prostate also is periodically and frequently secreting small amounts of fluid during the "resting" stage (dog not being used at stud). Up to a couple of cc's per hour can be normal during this resting phase and is eventually either dropped on the ground or licked clean. (If all this turns your stomach, you need to collect spoons or embroider, not raise dogs.) The process is much accelerated when the stud is aroused by a bitch in season.

The concentration of viable sperm ejaculated at a dog's first breeding after a time of abstinence may be quite low, especially if a bitch in season is brought in suddenly. The second ejaculation (second tie or artificial collection) yields not only a much greater sperm count, but much greater seminal/prostatic fluid volume as well. The second time the two are bred during the bitch's same season, then, has a better chance of being successful. People may not realize why, but this is the real reason for most people insisting on at least two ties unless the stud is being used once or twice a week immediately before their own bitch is presented for service. A male who is kenneled next to a bitch in season or who has been "teased" by such a bitch for a long while or repeatedly before being allowed to mount her (perhaps half a day or more) will also have a greater ejaculate volume, including more sperm, on the first breeding. It is important not only psychologically, but physiologically (and economically if you only get one shot) to allow time to play and time for the stud to build up a good reservoir and production rate.

The normal size range of the prostate can show considerable variance even in dogs of the same size, with several factors accounting for this including age, breed, body weight, general condition, hormones, and perhaps heredity and other influences. Pathological causes of atrophy (shrinking) or hypertrophy (enlargement), mostly the latter, include cysts, abscesses, cancer, inflammation from some other agent, and benign enlargement due to increased prostatic production or some unknown stimulus. In a 25 pound dog the gland may be about the width of your thumbnail, while in larger breeds it may be the size of a walnut or two inches in diameter.

Older dogs (over 5 years of age) commonly have benign enlargement, which is thought to be due to a change in the androgen/estrogen hormone balance. Enlargement to as much as three inches diameter is not uncommon. Dogs who are made to retain urine for long periods of time are more likely to have such enlargement, and since this can lead to cyst formation, it may be a good idea not to let your house dog have a salty supper and free access to water and then let his bladder fill and stretch, stressing his prostate while you blithely snore away for eight hours. Dogs should have plenty of water, but they should also have frequent opportunity to void their bladders. You'll probably delay kidney trouble as well as prostate problems if you take your dog out more often just before retiring to bed.

SYMPTOMS

Sometimes symptoms of hypertrophy may be overlooked by the dog owner until the disease or disorder has progressed to a more serious stage. If the dog periodically strains to move his bowels and you can rule out the possibility of his eating shoe soles or other indigestible garbage, it may be that a constant or cyclic enlargement of the gland is nearly closing off the end of the colon. Likewise, inflammation and enlargement can interfere with passage of urine from the bladder to the urethra, and the dog may strain or take "forever" to urinate. Often you will notice a thin stream, dribbling, a pulsating squirting, or a combination. The only stud dog we ever had to develop prostatic symptoms took a little longer to urinate but what really caught my eye was a drop of blood on the snow when he finally finished urinating.

Because infection is sometimes a part of the problem, fever can be one of the symptoms, but this is seldom checked unless other signs are seen first. Even rear-limb lameness can be a symptom. Knowing where the prostate lies, you might even be able to press your fingers up on the abdomen in that area and feel it. If the dog evinces considerable pain rather than mild discomfort, he may have prostatic disease.

DIAGNOSIS

When the examining veterinarian palpates the prostate, he tries to determine not only the size but also the shape, as there may be preferential swelling on one side more than the other, and this may be a determinant in which side to enter if surgery is needed. If mobility is poor, this probably means an abscess or a neoplasia has formed, while with benign enlargement of cysts the gland tends to move around more freely on probing. Neoplasias such as leiomyoma or carcinoma are less frequently seen than other enlargements but, if not tended to, can spread to other organs. It is very important to realize that more than one disease process can and often do occur concurrently. Sometimes a neoplasia (cancer or tumor) will develop an abscess, sometimes an abscess will form as a result of cyst growth, etc.

Besides palpating, your veterinarian will want to do a lab work-up including blood and urine analyses. These will give more clues as to the nature of the disease and will tell him if kidney disease, urinary tract infection, or other concomitant disorders are present. Radiographs may be suggested so the doctor can search for cancer spreading to lymph nodes or bones or other areas. However, unless something like that is found, it is unlikely you will get a positive diagnosis even with x-rays, since so many things can cause enlargement and not show signs elsewhere. Before going too far in the diagnostic workup and treatments, you must discuss with the vet such things as costs of each step, the value of the dog as a stud, the chances or advisability of keeping him intact (capable of producing sperm and offspring), the presence of systemic disease, and other questions.

TREATMENT

Our dog was treated successfully with an antibiotic, though the rate of success with this approach is not impressive. Unfortunately, many of the common antibiotics are not absorbed by prostatic tissue and those that are, such as erythromycin, are not effective against the more common microbial pathogens involved with prostatic disease. It seems chloromycetin, Tribrissen, or a cephalosporin do the most good against inflammation.

I mentioned hormone therapy before. It is known that testosterone ("Male hormone") enlarges the prostate and estrogen ("female hormone") shrinks it, but as long as the testicles are there, some testosterone will continue to be produced, even with estrogen injections, making the latter less effective. Further, estrogens can suppress bone marrow (blood is produced there) and cause squamous metaplasia, a change in the cell nature of the tissue. Castration is the treatment of choice, because when male hormone production ceases, the prostate gland usually shrinks back to normal or smaller. If done early enough, it can be all the surgical treatment needed, and may not even need any Estradiol (estrogen) dose with it.

Some types of prostate disease require something more than castration alone. A cyst may be cut and attached to an opening in the dog's side and allowed to drain minuscule amounts indefinitely. An abscess might be drained through tubes exiting the abdomen off to the side of the penis. The tubes are usually removed about a week after surgery. Prostatectomy, which is partial or complete excising of the gland, is a very difficult and dangerous operation. The dog that needs this may not have control of his urination, and peritonitis often occurs.

If you are observant, and monitor your dog's stools and urinating habits, instead of just turning him out on his own, you can probably catch a lot of problems early enough that they will respond to the simpler, less costly treatments. If you don't have a breeding quality male (actually, the best one in a considerable mileage radius) you might want to consider castration as a means of preventing most causes of prostatic problems. It will also have other benefits, such as freedom from worry about quarantining him from your bitches when they come in season.