In the first article in this series, we looked at what can make a female dog incontinent. In this article we will explore the sequence of events that hopefully get you to a diagnosis.
How will my vet diagnose which type or types of urinary incontinence are present? If your female dog has urinary incontinence, your veterinary surgeon will use a combination of careful history taking and diagnostic tests to help get to the root of the problem. If all other causes of incontinence are ruled out, it means that a diagnosis of congenital or acquired urethral sphincter mechanism incompetence can be made.
History taking
‘History taking’ by your veterinary surgeon is a critical first step. Examples of the questions that they will ask you include:
How old is your dog?
What breed is she?
Does she walk around dribbling urine?
Are the urinary accidents mainly when she is relaxed or sleeping?
Is there a normal stream of urine when going to the toilet outside?
Is there an odour or colour change to the urine?
Has she had her first season yet or is she neutered?
Does she drink excessively?
There are many questions that should be asked, so that your vet can build up a clear picture of exactly what is happening at home.
Fig 1: Your vet will need to examine your dog thoroughly and carry out various tests so that they can find out the cause of the urinary incontinence.
Examination The physical examination can quite often reveal no abnormalities or signs of a problem – most dogs with urinary incontinence are often otherwise well. Your vet will carefully inspect your dog for any signs of urine staining on the fur or secretions from the external genitalia.
Blood samples Blood samples are important to rule out any condition which may be causing an excess thirst and the production of dilute urine.
Urine samples These can be caught ‘free catch’ (ie as your dog is urinating). Urine samples are useful to see if there are any inflammatory cells, protein or microscopic blood particles present. Glucose and ketones will also be highlighted if your dog is diabetic. Importantly, the concentration (what is known as the ‘specific gravity’) of the urine should be measured to check that your pet is able to concentrate her urine and show that her kidneys are working properly.
In order to get the best urine sample for bacterial culture and to test antibiotic sensitivity, your veterinary surgeon will collect a urine sample in a sterile fashion by inserting a needle into your dog’s bladder (a simple procedure called ‘cystocentesis’) via ultrasound guidance or by careful, accurate localising of the bladder.
Imaging There are several forms of imaging which can be used either alone or in combination with each other to assist in the diagnosis of the urinary incontinence.
Ultrasound will be able to determine a lot about the architecture of the kidneys, the outline of the bladder, the dimensions of the ureters (these are the 2 tubes which carry urine from the kidneys to the bladder) and your vet may even be able to see jets of urine squirting into the bladder from the ureters, which means that the ureters are entering the bladder where they should. This study is often performed under sedation.
Fig 2: This is an x-ray which has been taken after contrast liquid has been injected via a catheter into the bladder. The yellow arrow shows the contrast liquid in the catheter leading into the bladder. The red arrow shows the bladder which is full of contrast liquid. The blue arrow shows a ureter – this ureter is ‘ectopic’ and enters the bladder further back than where it normally should.
X-rays with contrast agent often give a wonderful overview from the kidney all the way along the urinary tract to the urethra (the urethra is the tube which takes urine from the bladder to the outside). A ‘contrast agent’ is a liquid that appears white/opaque on the x-rays and highlights the outline of various anatomical parts. Contrast can be injected into one of your dog’s veins (known as ‘intravenous urography’) or via a series of catheters from the vulva into the bladder (a procedure called ‘retrograde vaginourethrograhy’). This series of x-rays are taken over a period of 15-20 minutes to see how the contrast, which is mimicking the flow of urine, passes along the urinary tract. Contrast x-rays will sometimes highlight the ureters opening into the bladder in the wrong place (‘ectopic ureters’) but not always, and further tests may be needed such as ultrasound, CT scanning or cystoscopy. Pets require an enema prior to this x-ray contrast study, as faeces in the large bowel can otherwise obscure the contrast. It is performed when your dog is under general anaesthesia.
Fig 3: A computerised tomography (CT) scan uses X-rays and a computer to create detailed images of the inside of the body, viewed in ‘slices’.
A CT scan with liquid contrast injected into a vein is an excellent way to very clearly see the urinary tract anatomy. Many universities and veterinary referral centres have in-house or visiting CT machines. After the contrast liquid has been injected, scans are performed immediately then at intervals over a 15 minute period. The contrast liquid gradually flows from the kidneys into the ureters and bladder. This is a very accurate method of seeing more specifically where the ureters insert into the bladder. This can be performed under deep sedation or general anaesthesia and does not require an enema.Cystoscopy
In Part 3 of Urinary Incontinence in the Female Dog, we will look at the current options for managing urinary incontinence.
About Catherine Sturgeon
Catherine qualified from the Royal Veterinary College in 1994 and with a passion for soft tissue surgery, she has become a recognised specialist of both the Royal and European College of Veterinary Surgeons. Catherine has been exposed to hundreds of cases, giving her the practical ‘know how’ to assist any patient with a soft tissue surgery problem. A pet lover through and through, Catherine has a pampered cat and a Lurcher with selective hearing.
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