Urinary Incontinence In Dogs

dog no urination sign

 
Urinary incontinence is when there is passage of urine without conscious control. A dog will not know that they are going to release urine. It is not deliberate urination due to lack of house training, or intentionally urinating to make a point.

There are a number of conditions and diseases that can cause uncontrolled urination. The cause of the urinary incontinence determines the treatment.

 
 

 
 

Urinary incontinence is not frequent urination

Urinary incontinence is not just frequent urination. There are a number of diseases that can cause a dog to need to urinate frequently. Incontinence is the involuntary release of urine, whereas in diseases that just cause frequent urination, a dog is aware that they have to urinate.

Using Cushing’s disease as an example, since it is quite common. A dog may be urinating during the night, or when they are left in the house without access to the outside for extended periods. The reason is that a dog with Cushing’s disease is drinking so much that they make such a large volume of urine, so that they are unable to hold it all night or for extended periods – so eventually they have to go. (See symptoms, diagnosis and treatment of Cushing’s disease for more information).

Another common cause of frequent urination is bladder infections. (See urinary tract infections: bladder (cystitis) & urethral infections for more information)

Your vet will determine whether the cause of the changes in the pattern of urination is due to a disease that causes frequent urination, or whether urinary incontinence has developed.

Urinary incontinence is not submissive urination (stress incontinence)

Some dogs when stressed or upset will pass urine. This is a behavioral condition and occurs in response to stress or upset. When exposed to stress some dogs will contract the abdominal wall muscles and relax urethral muscles, which cause the bladder to empty. This is most common in young puppies and many will outgrow it. (See submissive urination, causes and treatment, for more information).

Dogs with submissive urination will urinate normally when not stressed.

What are the symptoms of urinary incontinence?

Dogs with urinary incontinence will often pass some urine when they are relaxed and sleeping. For this reason you may notice damp spots on the dog’s bed and/or the bed might start to have a smell of ammonia. You may notice a damp spot when a dog gets up from a spot where they have been relaxing.

Some dogs will dribble urine when they are moving around.

Dogs with some types of urinary incontinence may start to urinate more frequently.

The leaking of urine can mean that the area round the penis or vulva may frequently be damp with urine. This can lead to irritation and scalding. This can become quite painful for a dog.

Some dogs with urinary incontinence may get urinary tract infections.

What are the major causes and treatments of urinary incontinence?

The major causes of urinary incontinence are due to low levels of sex hormones, age-related muscle weakness, defects in anatomy (birth defect), problems with the nerves that control the bladder and over filling (overdistension) of the bladder.

Hormone-responsive urinary incontinence

Hormone-responsive urinary incontinence is the most common form of urinary incontinence.

Hormone-responsive urinary incontinence is found most frequently in spayed middle to senior female dogs, more commonly in large breeds. It is less frequent in senior neutered males. Occasionally this type of urinary incontinence occurs in spayed young female dogs, neutered male dogs less than 9 years and intact dogs.

At the bottom of the bladder there are several muscles that remain contracted to keep the urine, as it collects, in the bladder. Normally the emptying of the bladder occurs when a dog consciously relaxes these muscles. The maintenance of strength of these muscles is in part controlled by hormones. In females the hormone is estrogen, and in the males the hormone is testosterone.

Spaying or neutering reduces the levels of these sex hormones; plus the level of these hormones decrease in all dogs as they age. This is why the occurrence of hormone-responsive urinary incontinence is found most frequently in older spayed or neutered dogs.

Treatment of hormone-responsive urinary incontinence

There are two treatments for hormone-responsive urinary incontinence; replacement hormones or phenylpropanolamine. Which one is tried first depends on the preferences of the vet, the age of the dog and whether the dog is intact.

For females the replacement hormone is a synthetic estrogen, diethylstilbestrol (DES). This drug is normally given daily for the first 7 to 10 days and thereafter once per week. Long term daily administration can lead to side effects including bone marrow suppression which can lead to aplastic anemia, hair loss, and a range of problems with the reproductive organs. Spayed female dogs on a once a week dosing schedule are at a low risk of serious side effects.

For males testosterone injections may be used to treat urinary incontinence. Testosterone is generally much less effective than DES is in female dogs. Therefore, the first choice of drug for a male will often be phenylpropanolamine.

Phenylpropanolamine (PPA; Proin, Propalin) is effective in many dogs (male and female) for treatment of urinary incontinence. This drug acts on the muscles below the bladder increasing the level of contraction these muscles. The improved level of contraction helps to stop urine leaking out of the bladder. PPA has been unavailable at times due to its use and abuse as a diet aid (e.g. Accutrim). Side effects can include restlessness, increased blood pressure and loss of appetite.

Age-related urinary incontinence

In dogs like humans, after a certain age muscles start to weaken. In some dogs the muscles at the base of the bladder may weaken enough to not completely hold the urine. Treatment is most commonly with phenylpropanolamine (see above).

Dogs that are senile may not have complete control of the bladder and may dribble urine.

Urinary incontinence due to defects in anatomy (birth defects)

There are a number of possible birth defects that can cause urinary incontinence. Ectopic ureter(s) is the most common.

The ureters are the tubes that carry urine from the kidneys to the bladder (diagram of the dog urinary system). There are two ureters, one from each kidney. Occasionally, one or both the ureters instead of connecting to the bladder can connect to the urethra (which connects the bottom of the bladder to the outside), vagina (in female dogs) or other incorrect location. If a ureter connects to the urethra or the vagina then the bladder will be bypassed and there will be urine leaking out.

Ectopic ureters do not become apparent until a puppy is several months old and are becoming housetrained. If only one ureter is affected the puppy will urinate normally in addition to dribbling urine. If booth ureters are affected the puppy will only dribble urine.

Ectopic ureters are more common in female than male dogs.

Breeds that have a predisposition to ectopic ureters are Siberian Huskies, Toy Poodles, Miniature Poodles, Collies, Labrador Retrievers, Fox Terriers, West Highland White Terriers and Welsh Corgis.

Due to the inappropriate drainage, it is common for puppies with ectopic ureters to get kidney or bladder infections.

Depending on the anatomical defect, corrective surgery may be effective. The ureter will be detached from the incorrect location and attached to the bladder.

Urinary incontinence due to problems with the nerves that control the bladder

There are a number of problems with the nervous system that affect control of the bladder. These include inherited defects in the nervous system, cancer, brain and spinal cord injuries.

Incontinence can be due to not having effective control of either the bladder itself or the muscles at the bottom of the bladder.

Not being able to consciously contact or detect that the bladder is full, will result in spontaneous emptying of the bladder when it becomes overfull. Lack of nervous control of bladder contraction is diagnosed by using a catheter to add increasing volumes of fluid to the bladder and measuring how forcefully the bladder contracts.

Treatment depends on the cause of the urinary incontinence. If the urinary incontinence was due to damage a part of the nervous system, control may be regained as the damage heals. Catheterization to empty the bladder is an option if there is no immediate treatment option. This controls the exit of urine and stops irritation and urine scald on the skin. Due to the increased risk of infection with long term catheterization, dogs are usually treated with antibiotics.

Urinary incontinence due to overdistension of the bladder

When the bladder becomes over full and is over stretched, there is an involuntary (not under conscious control) relaxation the muscles at the bottom of the bladder and urine is released.

Partial blockage or stenosus (narrowing, also called stricture) of the urethra can cause urine to back up. This can cause the bladder to be very full of urine and become overdistended. This can then cause the release of urine which will cause dribbling.

Overdistension of the bladder can be caused by the presence of a tumor in the bladder, stenosus of the bladder or the presence of bladder stones. All of these can cause an involuntary release of urine.

Treatment depends on the cause.

In conclusion

There are a number of potential causes for urinary incontinence in dogs.

The most common cause of urinary incontinence is low levels of sex hormones, particularly in middle aged to senior female dogs that have been spayed. Other causes of incontinence include age-related weakening of muscle, birth defects, problems with nervous control of the bladder and overfilling of the bladder. The reason for the urinary incontinence determines the treatment.

 
photo credit: ♥ellie♥