Prostate Disease in Dogs: The Dog Owner's Guide

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If your dog is male, be that entire or neutered, he has a prostate gland and you should read this guide. The trouble is that this seemingly insignificant gland can cause a lot of problems; indeed an eight-year old entire male dog has an 80% chance of developing prostate disease.

If that statistic causes a sharp intake of breath – don’t worry. Unlike in people, the main cause of canine prostate disease is NOT cancer, but a hormonally driven enlargement of the prostate gland. Indeed, there are a rich variety of conditions that can affect this male gland, and there’s so much more to canine prostate disease than just cancer.

The flip side of the coin is that prostate disease is common and it’s uncomfortable.  So for the sake of your dog it pays to be familiar with the signs so you can seek prompt relief for his discomfort. But first, let’s familiarize ourselves with some basic anatomy and the root cause of the distress: the prostate gland.

Basic Anatomy

No! Don’t skip this bit, it helps you understand both the symptoms and why certain tests are necessary.

OK, first things first. Only male dogs have a prostate gland, and its job is to produce special fluid to keep sperm healthy during impregnation of the female. The prostate is plum-shaped, with a smooth ridge down the middle dividing it into two lobes.

The gland nestles around the urethra (the tube the dog pees through) where it leaves the bladder. Beneath is the bone of the pelvic brim, and directly above is the rectum, and above that more pelvic bone.

This anatomy accounts for some of the symptoms and problems associated with prostate disease:

• The prostate sits within the cramped bony box of the pelvis (although occasionally in some dogs it sits further forward and drops down into the abdomen). This leaves little room for enlargement, and so if the prostate gets larger; it squashesneighboring structures such as the rectum.
• The prostate gland sits around the urethra, like pastry round a sausage-roll. This makes surgical removal very challenging, if not impossible. Thank goodness then that other treatment options are available.
• This intimate relationship between prostate and urethra means that an inflamed prostate gland often seeps blood into it, so you might see blood spotting at the penile tip.

Well done. If you got this far you survived the anatomy lesson.

Which Dogs are Most at Risk?

No male dog is immune to prostate disease. By far and away the most common cause is a hormonally fed enlargement of the prostate called benign prostatic hyperplasia or BPH (more of this later). The chances of BPH increase with age, until we reach that figure of 80% by eight years of age. However, this doesn’t mean all dogs show signs at this age. That enlarged prostate may not cause an obvious problem until the dog is in his teens.

Unfortunately, prostate cancer can and does occur – albeit rarely. This is slightly more likely to happen in neutered dogs than entire, and is again the territory of the older dog, usually over the age of ten years.

The Signs to Watch For

If the dog isn’t showing signs, then you can relax. Prostate disease is NOT a condition you have to detect early in order to stand a chance of successful treatment. Happily, the majority of dogs respond well to therapy once they show signs and a diagnosis made.

These symptoms are all associated with prostate disease; with those at the top being more common than those at the bottom are:

• Straining to pass feces
• Blood or pus dripping from the penile tip (not associated with passing urine)
• Blood in the urine
• Difficulty passing urine
• Lethargy
• Abdominal discomfort
• Weight loss
• Fever

Of course, each of these signs is not the exclusive domain of prostate disease, but if you notice one or more then a trip to the veterinarian is always advisable no matter what the cause.

Let’s take a look at this list in more detail.

Straining to Pass Feces

Think of this problem like putting your foot on a hosepipe: The pressure on the hosepipe stops water flowing. Only in this case, the rectum is the hose and the prostate in the foot. The lack of space with the pelvis means an enlarged prostate pushes up on the rectum and makes it difficult for the dog to pass feces.

These dogs typically squat for ages, and perhaps walk around in a squat as they try to do their business. They may even produce some liquid from the anus, followed by a hard stool.

Blood in Urine or Dripping from the Penile Tip

Just like when you scratch an itch and make your skin bleed, so an inflamed prostate gland can seep blood. Because of its intimate anatomical relationship with the urethra, the blood tends to drain away into it and is either flushed out when the dog pees, or it drips down under gravity. You might notice this as drops of blood staining your dog’s bed, or the occasional drop of blood hanging from the tip of the dog’s sheath.

Abdominal Discomfort, Fever, and Weight Loss

The dog seems unwell, lacks energy, his coat becomes dull and he may be listless. He may stop eating, and withdraw in himself. This was the presentation of a wonderful black Labrador I treated for prostatitis.

His illness seemed very general and there were no real clues as to the seat of infection, until I gave him a gentle rectal examination. Through the wall of his rectum the infected prostate generated heat like a burning coal, and the gland wasexcruciatingly painful even to the lightest touch.

These signs are less common and tend to occur in one of three reasons:

1)    The prostate gland is infected, which is the commonest reason for fever-associated with prostate disease

2)    The hormonal disease BPH (See later) has progressed beyond the “harmless” stage because early signs were missed.

3)    Some forms of prostate cancer.

This is one of the reasons early treatment is preferred, because it could save your dog from complications and increased discomfort.

What Types of Prostatic Disease are there?

I’ve teased you by mentioning there are several types of prostatic disease. For the sake of completeness they are listed here, but some are much more common than others are, and it’s these we will then take at look at in detail.

• Benign prostatic hyperplasia (BPH)
• Bacterial prostatitis
• Prostatic cysts
• Prostatic abscess
• Prostatic calculi
• Prostate squamous cell metaplasia
• Prostatic cancer

You veterinarian will want to make a diagnosis, because each condition requires different therapy.

How Does My Veterinarian Reach a Diagnosis?

The first and most basic test is to assess the size, shape, and texture of the prostate by feeling it. This is done “per rectum” and is where the veterinarian dons a glove, lubricates his finger, and gently inserts it into the dog’s anus.

Most prostate’s sit just within finger’s reach and can be felt in its location just below the rectum. The exception is large or giant breeds, where the larger size of the dog and the weight of an enlarged prostate may drag it over the edge of the pelvic brim and out of reach into the abdomen.

The vet can tell a lot about the nature of the problem from factors such as if the gland is larger than normal, if it’s symmetrical and if it’s painful. From this he can decide what tests are needed. This may be either an ultrasound scan of the prostate or x-rays of the dog’s abdomen and pelvis. The prostate is never looked at in isolation and the bladder and structures around the prostate are also checked.

If all the signs are pointing toward the prostate disease, then a prostatic wash may be in order. This is where a small volume of saline is introduced into the urethra near to the duct into the prostate; the gland massaged, and then sloughed off cells sucked up in the saline. The sample is split into two, and part is smeared on a microscope slide and the remainder sent for culture to see what bacteria are present. Looking at the cell types can give valuable clues as to the nature of the problem.

If a diagnosis is not forthcoming, or if more information is needed, then a MRI scan is the next step. This often requires referral to a specialist. So for arguments sake let’s assume your veterinarian reached a diagnosis and take look at the most significant problems, the specific symptoms associated with them, and appropriate treatments.

Benign Prostatic Hyperplasia

This condition is very common, and don’t be intimidated by the name, which basically means a non-cancerous enlargement of the prostate gland. This is an age-related condition (most likely to affect those over 5 years of age) and does not occur in neutered males. This is because the cause is testosterone constantly stimulating the prostate gland, and over time causing it to enlarge.

The problem is not painful in itself, but the enlargement in a cramped space causes problems, especially passing feces (remember the “foot on the hosepipe” scenario?) The symptoms are usually those of straining to toilet, and drops of blood at the penile tip. However, left untreated, the fecal straining can cause a rectal hernia to form, which also needs treatment – so better to step in early.

The therapy is to stop testosterone from feeding the prostate gland. Traditionally the answer was to neuter the dog, which removes the source of testosterone, and then wait for the prostate to shrink down. Alternatively, for those infirm patients not able to cope with an anesthetic, monthly injections of Tardak (delmadinone), a drug from the progestogen family, can be given which chemically cancels out the testosterone and therefore its effects.

However, there are now new and highly effective options available. The first is a Suprelorin (deslorelin) implant which is effectively a slow-release chemical castration. This small wax impregnated plug is injected under the skin and releases active ingredient for 6 months.

The final alternative is Ypozane, (osaterone) a tablet taken daily for seven days. This blocks receptors on the prostate from recognizing testosterone, and one course of tablets is effective for seven months.

Prostatitis

This infection and inflammation in the prostate. These dogs can become unwell quickly and typically have fever, appetite loss, and malaise. Sometimes the condition is an extension of a urinary infection, in which case the dog is uncomfortable and passes bloody urine, and becomes increasingly unwell as the prostate becomes involved.

Antibiotics are key to settling this problem. Where possible it’s best to culture the bacteria involved so that a precise choice of effective antibiotic can be made. Many antibiotics penetrate poorly into the prostate so it’s often necessary to give antibiotic therapy for three weeks or more.

Prostate Cancer

And finally, prostate cancer. This condition is slightly unusual because statistically it’s slightly more likely to occur in a neutered dog than an entire one. The exact reason for this is not known, and the difference is only slight so this is not a valid reason not to get your dog doctored.

In the early stages the signs are similar to BPH, and even specialists have been known to mistake cancer for BPH. However, if the dog is given treatment for the later, and yet the problem doesn’t settle, then it may be a prostate biopsy is necessary. The drawback with this is that the prostate is relatively inaccessible and surgery to get a sample of tissue can be tricky.

As the problem progresses, some dogs develop ahind limb lameness. This is because the cancer has spread to lymph nodes that sit in close association with the spine, and press on the nerves to the back legs.

Unfortunately, because the prostate gland is so intimately associated with the urethra, surgery is rarely successful. The symptoms can be managed for a while using mild laxatives, such as lactulose to keep the stool soft and make them easier to pass.

Prostate cancer in the dog is painful, so pain relief might also be necessary. As the gland enlarges, it can decrease the diameter of the urethra and make it difficult for the dog to pass urine. Once things get to this stage, and given the grave outlook, hard as it is to let a beloved dog go, the kindest course of action is to make sure the dog doesn’t suffer and say a final goodbye.

But let’s not get too hung up on prostate cancer – it is after all quite rare. Your male dog is more likely to suffer from hormonal enlargement than all the other conditions put together and remember -BPH is extremely responsive to treatment.

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