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Urinary Incontinence in Dogs

overview

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Urinary incontinence is the process of involuntary urination. This can vary from tiny drops to a full urination, but is not consciously controlled. There are several causes of incontinence, which can be broadly separated into anatomical abnormalities or failure of normal function. Incontinence can also happen in very old dogs due to cognitive dysfunction.

Anatomical abnormalities cause incontinence in young dogs, though they are rare. Many puppies will urinate a small amount when excited. If this is excessive or does not resolve by 6 months of age, it may suggest an underlying problem. The most common anatomical abnormality is ectopic ureters. This is when one or both of the tubes connecting the kidney to the bladder attach too far down the bladder neck. They bypass the muscular sphincter which holds urine in the bladder, causing incontinence.

Functional causes of incontinence tend to develop later in life, though this is not always the case. The most commonly diagnosed is urethral sphincter mechanism incompetence (USMI). This is a failure of function of the urethra, the tube between the bladder and the outside world. Normally, the urethra closes when the dog is not urinating, but in USMI it is weak and does not fully close, allowing urine to trickle past. USMI is significantly more common in neutered females, but it is not fully understood why this is the case.

symptoms

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What are the symptoms of urinary incontinence?

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Urinary incontinence is mostly commonly seen in female dogs, only rarely affecting male dogs or cats. Often, urine leaking will occur when the dog is relaxed or asleep, and wet patches on the bed are a common finding. Urine is also likely to leak if abdominal pressure increases, such as during barking or coughing. In those most severely affected, urine can leak constantly, sometimes without the dog ever passing a normal conscious urination.

diagnosis

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Which tests are used to diagnose urinary incontinence?

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Definitive diagnosis can be challenging, and it is essential to be sure that the symptoms are truly due to incontinence. A thorough history and consideration of your dog’s age and breed will help with this.

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Examination

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Specifically, your vet is likely to palpate the bladder, assess the vulvar area, and examine the back end and legs for signs of orthopaedic pain or neurological dysfunction.

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Blood tests

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Many organ disorders can cause increased thirst and urine production, which can lead to urine leaking. General blood tests can help to rule out other underlying conditions.

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Urinalysis

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Urinary tract infections or behavioural problems can cause pets to urinate inappropriately. Examining the urine, and checking for infection, can help guide treatment.

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Imaging

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Both radiographs (x-rays) and ultrasound can be useful to examine the urinary tract. Your vet may recommend a contrast study, in which contrast (fluid that shows up on x-ray) is administered into the blood stream or straight into the bladder to help identify abnormalities. Occasionally, advanced imaging such as CT scanning or endoscopy of the bladder is advised.

A lot of the aforementioned tests are used to rule out conditions that can mimic true incontinence. Sometimes, once common underlying conditions have been ruled out, it is appropriate to trial treatment. This is not always suitable, and your vet will advise if this is the case.

treatment

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How is urinary incontinence treated?

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Due to the variety in types and severity of incontinence seen, various treatment options are available:

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Medical

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Several medical treatments for incontinence exist, and are usually used for functional disorders such as USMI. Treatments work by increasing the contraction of the bladder neck and urethra, and lead to significant improvement in up to 90% of cases. Different drugs have different benefits and side effects, and individuals may respond to one option better than another. Medications manage but do not cure the condition and must be taken daily for life. Some animals may manage with reduced doses long-term, while others become refractory to treatment and need higher doses or different drugs.

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Surgical

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Incontinence due to anatomical abnormalities, such as ectopic ureters, are best treated surgically if the abnormalities can be corrected. This can resolve the problem, or medical management may be required long-term in combination.

For dogs with USMI who are not responding well to medical management, or who are experiencing side effects, surgical treatment can be attempted. Several techniques can be used to increase the resistance within the urethra, including collagen injections, artificial sphincter placement, and a procedure called a colposuspension. None of these have 100% success rates, and often specialist referral is required.

outlook

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What is the outlook for dogs with urinary incontinence?

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The prognosis for dogs with urinary incontinence is good, with the vast majority responding well to treatment and achieving a good level of control. A small number of dogs are harder to control and may require multiple medications, or varying doses, to manage successfully.