Abscesses are one of a number of conditions that can affect the prostate in male dogs. The prostate is a gland that surrounds the urethra close to where it leaves the bladder, and it produces some of the fluid components of semen. During ejaculation, the prostatic fluid is released into the urethra to join semen from the testes. 

An abscess is a condition when infection becomes established inside the gland. This causes it to swell and fill with infected fluid. And although they aren’t that common – roughly 6% of male dogs will develop an infected cyst, but not all of these go on to become abscesses – they are potentially serious. Here are five key things you should know about prostatic abscesses in dogs. 

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1. Older dogs tend to be affected

In older, intact (unneutered) male dogs, the prostate frequently enlarges because of hormonal changes over time. This enlargement is known as benign prostatic hyperplasia (BPH). Although many dogs won’t be unwell because of this, it does make them more susceptible to developing other conditions including abscesses and cysts which can be more serious. 

2. In a dog with a prostate abscess, you might suspect a urinary tract infection

The signs of a prostatic abscess can be variable. Owing to the close relationship with the urinary tract, it may cause signs that mimic a urinary tract infection. These include blood in the urine, straining to urinate, frequent urination or dribbling urine.

Alarm bells start ringing for prostate disease when we see other key signs too, for example, when we see a male dog that struggles to pass faeces or appears constipated. This is because pressure on the colon from an enlarged prostate makes it harder for faeces to pass by. Additionally, dogs with very large prostates may also have difficulty walking, perhaps being lame in the rear legs or having an abnormal gait. Other, more generalised, signs of a prostatic abscess may be that the dog is more tired, less keen to eat or shows signs of abdominal pain

3. An enlarged prostate can mean an abscess, or many other things

So, apart from BPH, an enlarged prostate could mean an abscess but it could also mean various types of prostatic cysts or even neoplasia (tumour). We often see dogs with BPH that have inflammation (prostatitis), prostatic cysts or prostatic abscessation at the same time.

When we suspect a prostate problem, we will try to have a feel of the gland by rectal exam, and in many cases your vet will be able to appreciate an enlarged gland. Some dogs with abscesses, prostatitis or neoplasia will be quite sore, so they might not tolerate a rectal exam. The next step is generally a urine sample and blood testing to check the general health of the dog and start to narrow things down.

Then, we perform radiographs and an ultrasound scan. This gives us a good look at the prostate and bladder and it can help us figure out whether the dog is likely suffering from BPH, prostatic abscess, cysts or a tumour. We will often take further samples of urine and the prostate fluid for a culture to check if infection is present and what antibiotics can be used to help treat an abscess. 

4. Just antibiotics won’t treat a prostate abscess

Proper treatment of a prostate abscess generally means surgery. Although we might suspect an abscess because of the signs and the appearance of the prostate on ultrasound, we can’t just give antibiotics and expect it to clear up. The prostate is a difficult gland to penetrate with antibiotics. particularly where there is an abscess because part of the gland may be necrotic (dead tissue) and therefore not have any blood supply.

As a result, we have to use antibiotics in conjunction with surgery. We will start antibiotic therapy when we suspect a prostate abscess, but really it needs to be drained and treated by castration and prostatic surgery. Castration reduces the activity and inflammation within the prostate gland, causing it to reduce in size. In this way, it helps to speed up resolution and prevent recurrence of prostatic disease.

At surgery, we open the abdomen and drain the abscess. We can then send samples that are retrieved at surgery for culture and sensitivity testing. This is to ensure we are using the correct antibiotic for the bacteria causing the infection.

5. We can do interesting things with surgery for prostatic abscesses!

When we take a dog to surgery for a prostatic abscess we are aiming to remove as much of the abscessed tissue as possible (and other cysts if there are any) and help it to drain. This is a delicate procedure because of the close proximity of other important structures such as the urethra, bladder and ureters.

The removed tissue should be sent away to the lab not just for culture, but also to make sure there’s no sign of a tumour in the gland. Until recently, we mostly used methods such as placing a drain and even a procedure known as marsupialisation to drain the abscess.

Marsupialisation

Marsupialisation is a funky surgery where we suture the affected prostate to the abdominal muscle. We then open and drain the abscess, then suture it to the skin to allowed continued drainage to the outside. Unfortunately, it tends to be associated with more complications than the procedure we normally opt for now, which is omentalisation.  

Omentalisation

During omentalisation the prostatic abscess is first opened and debulked as much as possible. Then the omentum (which is like a protective, fatty and vascular mesh that extends from the stomach to cover all the abdominal organs) is pulled through the gland to loop around the urethra and is fixed back to itself as it leaves the prostate.

We like to think of the omentum as a biological plaster but it’s so much more. It improves the blood supply and immune functions in the abscessed prostate. This helps it to fight the infection and heal. This is very effective and isn’t associated with the same complications as marsupialisation, it tends to be better tolerated. However, as with all prostate surgery, omentalisation comes with the risk of incontinence. 

Prostatic abscesses can be really nasty, but they’re very treatable, especially if caught early. And they’re almost 100% preventable with castration, too.

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