Q: My 11 year-old Doberman has begun to leak urine. We usually find it in her bed in the morning, but it can occur anywhere she has been lying down. It is starting to make our carpets smell. Are there any options?
A: Urinary incontinence is a frustrating problem for dogs that live in our homes and sleep in our beds. My old Labrador, Ariel, developed this same problem, making us take steps to protect our home until we found a solution.
This problem is common especially in older female dogs and may be so frustrating for some owners that their indoor dog is kept outside or given up for adoption.
There are many factors that help maintain urinary continence. The most important is the muscle tissue in the urethra that prevents urine from leaving the bladder until the appropriate time. This muscle should keep the urethra closed until the dog is ready to void.
If the pressure in the bladder when it is full of urine exceeds the pressure the urethral muscle can maintain, then urine will leak out. The weaker the urethral muscle, the less urine it takes in the bladder before you find urine on your carpet.
The most common form of urinary incontinence in dogs is urethral sphincter mechanism incontinence (USMI).
Breed, body weight and tail docking appear to be risk factors. Old English sheepdogs, Doberman pinschers, German shepherd dogs, boxers, weimaraners, rottweilers and Irish setters have been found to have an increased risk.
Ariel did not read the study that found Labs to have a decreased risk. Dogs weighing more than 44 pounds are more likely to develop incontinence as well.
Spayed female dogs appear to be at an increased risk with historical studies indicating up to 20 percent of them developing some degree of incontinence. It is thought that the urethra contains receptors to estrogen and spayed females would have decreased hormonal levels.
In the April 1 issue of the Journal of the American Veterinary Medical Association, veterinarians at Red Bank Veterinary Hospital looked at 566 spayed female dogs.
Interestingly they found only 29 of these dogs (5.12 percent) developed urinary incontinence. They found no association between age at the time of the spay and development of incontinence. They also confirmed that larger dogs (those 33 pounds) were approximately seven times as likely to be affected.
When deciding how to treat, the first thing is to make sure there are no other problems that may contribute. Dogs with this condition do not know they are leaking urine. Dogs that consciously void inside have other problems and are not considered incontinent.
Incontinent conditions may include urinary tract infections, bladder stones and bladder tumors. Diseases that result in dilute urine may cause bladder pressure to exceed urethral pressure and let urine leak. Cushing’s disease, diabetes mellitus and renal failure are examples.
Any disease that may cause increased urine production or increased urgency to void should be eliminated as a potential problem before directly treating the incontinence.
Estrogens have historically been the drug used to treat urethral sphincter mechanism incontinence in spayed female dogs. Diethylstilbestrol (DES) is the most common form used. Possible adverse effects are heat-like behaviors, hair loss, behavioral changes and bone marrow suppression. Bone marrow suppression can be life threatening but it and other side effects are uncommon when dosed appropriately.
Phenylpropanolamine is another medication that will usually improve urethral sphincter strength. Potential side effects are anxiety, aggression, anorexia and hypertension, but as with DES, these are rare.
In dogs that do not respond to either medication alone, the combination is often affective. The estrogen “primes” the receptors on the urethra to phenylpropanolamine.
There are a small number of dogs who do not respond or cannot tolerate the medical therapies. There are still options for these dogs.
One option is to inject a substance into the urethra itself to narrow the opening. This requires general anesthesia and the placement of a scope in the urethra that allows a needle to be placed at the appropriate location.
In one large study, 68 percent of dogs were continent for about 17 months. This is usually not a permanent fix as the bulking material is slowly absorbed.
Several surgical procedures have been developed to improve continence. These entail bringing the bladder out of the pelvis and more into the abdomen. Around 50 percent of dogs are cured with these procedures.
Recently an artificial sphincter has been developed. This consists of a silicone ring that is placed around the urethra. A tube connects this ring to a port placed under the skin through which saline can be injected and allows the pressure to be adjusted. A study presented by veterinarians from The Animal Medical Center in New York at the 2011 American College of Veterinary Surgeons Symposium found improvement in continence in all 18 dogs participating.
Ariel stopped leaking when we started her on phenylpropanolamine. There are affective therapies available for urinary incontinence that will allow your dog to live back in the house and sleep in your bed again.
Dr. Henri Bianucci and Dr. Perry Jameson are with Veterinary Specialty Care LLC. Send questions to firstname.lastname@example.org.