Urinary Incontinence in Dogs

Overview of Urinary Incontinence in Dogs

Urinary incontinence is the loss of voluntary control of urination. Normal urination requires that the nerves and muscles of the bladder are working properly. In dogs, urinary incontinence sometimes may be confused with inappropriate urination. Inappropriate urination often is a behavioral problem. Diagnostic tests may be needed to distinguish between urinary incontinence and inappropriate urinations.

Probably the most common form of incontinence in dogs is called “primary sphincter mechanism” incontinence and is thought to be caused by weakness of the urethral muscle. It is most common in middle-aged medium- to large-size spayed female dogs.

Urinary incontinence can have neurogenic and non-neurogenic causes.

• Neurogenic causes of incontinence include those that are caused by abnormalities of parts of the nervous system involved in regulation of urination.
• Non-neurogenic causes of incontinence include congenital problems (abnormalities present at birth) such as a misplaced ureteral opening (ectopic ureter), over-distension of the bladder due to partial obstruction, hormone-responsive incontinence, and incontinence associated with urinary tract infection.

What to Watch For

• Dribbling of urine
• Finding of wet spots where the pet was sleeping
• Irritated skin from contact with urine

Finding wet spots in the house does not necessarily imply that the pet is incontinent. Pets with increased thirst and increased urination may urinate in the house due to increased urine volume and not being allowed outside frequently enough.

Straining while urinating and blood in the urine suggest other disorders such as bacterial cystitis or bladder stones.

Diagnosis of Urinary Incontinence in Dogs

Diagnostic tests must be performed to confirm the diagnosis of urinary incontinence and exclude other diseases that may cause similar symptoms such as bacterial urinary tract infection, urolithiasis (stones or calculi) or prostatic disease in male dogs. Tests may include:

• Complete medical history and physical examination, including palpation of the abdomen, rectal examination in males to evaluate the prostate gland, and vaginal examination in females
• Urinalysis to evaluate for presence of white cells, red cells, and bacteria
• Urine culture and sensitivity to evaluate for presence of bacterial urinary tract infection
• A complete blood count and serum biochemistry tests to evaluate the pet’s general health and function of other body systems
• Plain abdominal X-rays to evaluate for stones
• Contrast dye studies to evaluate for congenital abnormalities and bladder position
• In difficult cases, special physiologic studies of urination (urethral pressure profile, cystometrogram) may be recommended. These tests will require referral to a specialist.

Treatment of Urinary Incontinence in Dogs

Whenever possible treatment for urinary incontinence will be determined by the underlying cause. Definitive treatment involves elimination of the underlying cause of the urinary incontinence. Examples include correction of an anatomic defect, removal of a neurologic lesion, relief of partial obstruction, effective treatment of bacterial urinary tract infection.

In many cases, the cause of incontinence remains unknown after all diagnostic tests have been performed. In this instance, urinary incontinence must be treated symptomatically. The drug phenylpropanolamine is commonly used to treat urinary incontinence thought to be caused by weakness of urethral muscle (sphincter mechanism incompetence).

Home Care and Prevention

Administer medications prescribed by your veterinarian to your pet as directed. Allow your pet free access to fresh clean water and frequent opportunities to urinate. Make sure the bedding is clean and dry.

Follow-up with your veterinarian for examinations and urinalysis. If your pet has an inadequate response to treatment, additional tests may be necessary to identify the cause of the incontinence.

Contact your veterinarian if you notice any signs of urinary tract infection (e.g. straining, blood in the urine) or urinary obstruction (e.g. painful urinations, frequent unsuccessful attempts to urinate).

In-depth Information on Urinary Incontinence in Dogs

Other medical problems can lead to symptoms similar to those encountered in pets with urinary incontinence. These disorders should be excluded before establishing a diagnosis of urinary incontinence.

Causes of Urinary Incontinence in Dogs

Neurologic problems can cause urinary incontinence and can be divided into the following:

• Problems affecting voluntary control of urination, which are upper motor neuron problems. These include cerebral, cerebellar, brainstem and spinal cord lesions.
• Problems affecting the local nervous reflex arc that directly controls urination, which are lower motor neuron problems. These include trauma, tumor, infarcts, and nerve injuries.

A variety of non-neurologic problems can cause urinary incontinence including:

• Hormone-responsive incontinence, which are estrogen-responsive incontinence in female dogs and testosterone-responsive in male dogs
• Urethral sphincter mechanism incompetence
• Congenital defects, such as a misplaced ureteral opening or ectopic ureter present at birth
• Overflow incontinence due to partial urethral obstruction
• Muscle disorders of the bladder, as an over-active or under-active bladder muscle

Diagnosis

Certain diagnostic tests must be performed to confirm the diagnosis of urinary incontinence and exclude other diseases that may cause similar symptoms, such as bacterial infection, stones or calculi, or prostatic disease in male dogs. Tests may include:

• Complete medical history. The medical history may include questions about reproductive status (intact or neutered), urine dribbling during sleep or where the pet is lying, change in water consumption or urine production, presence of other illness, history of trauma, gait abnormalities that could suggest neurologic disease, blood in the urine, increased frequency of urination, history of urinary tract infections, previous drug therapy, constipation, and presence of behavioral problems.
• Physical examination including palpation of the abdomen, rectal examination in male dogs to evaluate the prostate gland, and vaginal examination in females
• Urinalysis to evaluate for white cells, red cells, or bacteria
• Urine culture and sensitivity to evaluate for the presence of bacterial urinary tract infection
• A complete blood count and serum biochemistry tests to evaluate the pet’s general health and other body systems
• Plain abdominal X-rays to evaluate for stones

Your veterinarian may recommend additional diagnostic tests to exclude or diagnose other conditions if preliminary tests do not yield a diagnosis, or to understand the impact of urinary incontinence on your pet. These tests are selected on a case-by-case basis. Examples include:

• Urinary catheterization to determine the amount of urine remaining in the bladder after the pet has attempted to urinate and to identify any obstruction
• Prostatic fluid analysis to evaluate for prostatitis in male dogs
• Contrast dye radiographic studies, such as cystourethrogram to evaluate the bladder and urethra, intravenous pyelogram or excretory urography to evaluate the kidneys and ureters.
• Ultrasound examination, a technique in which internal organs are visualized by recording reflections of ultrasonic waves directed into tissues, to evaluate for stones, tumors or obstruction.
• Urethrocystoscopy, a technique in which a rigid or flexible scope is passed into the vagina, urethra and bladder of females for direct visualization, to identify anatomic abnormalities, stones, or tumors. This procedure usually requires referral to a specialist.
• In difficult cases, special physiologic studies of urination, like urethral pressure profile or cystometrogram, to evaluate nervous control of urination. These tests require referral to a specialist.

Treatment

Treatment of urinary incontinence in dogs is based on the cause of the condition and other factors that must be analyzed by your veterinarian. There are several potential causes of urinary incontinence, and it is necessary to identify a specific cause to provide optimal therapy. Treatments may include the following:

• Sphincter mechanism incompetence in middle-aged, medium to large breed spayed female dogs may be treated with drugs such as phenylpropanolamine.
• Hormone therapy with estrogens such as diethylstilbestrol may be used in some cases.
• An over-active bladder muscle (detrusor hyperreflexia) can be treated with smooth muscle relaxant drugs such as propantheline.
• Urethral spasm causing functional obstruction of the bladder can be treated with the smooth muscle relaxant drug phenoxybenzamine.
• Functional obstruction caused by incoordination of the bladder and urethra, such as a bladder contracting against a closed urethra, also called reflex dyssynergia, can be treated with the smooth muscle relaxant drug phenoxybenzamine and bladder smooth muscle stimulant bethanecol.
• Urinary incontinence in neutered male dogs sometimes can be treated effectively with testosterone injections.
• In severe cases of weakened bladder muscle, it may be necessary to place an indwelling urinary catheter to keep the bladder empty for a prolonged time (7 to 14 days) during which recovery of bladder function can occur.
• A more permanent drainage device, a cystostomy tube, can be placed surgically to allow manual drainage of the pet’s bladder by the owner. This procedure is sometimes performed in pets with obstruction of the bladder by cancer.
• Ectopic ureters are treated by surgical repositioning, but this procedure does not always correct incontinence and drug therapy may be required after surgery.

Home Care for Dogs with Urinary Incontinence

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up is essential and may include the following:

• Administer all prescribed medications to your pet as directed.
• Allow your pet free access to fresh clean water.
• Follow-up with your veterinarian for examinations and urinalysis.
• Keep all bedding clean and dry.
• Examine your dogs genital area for any signs of a skin infection or irritation.
• Additional work-up may be necessary to identify other causes of urinary incontinence if your dog has an inadequate response to treatment.