Urinary incontinence is the involuntary passing of urine. The leakage can range from very minor and sporadic to quite severe and frequent. Dogs can be incontinent for many different reasons. Those reasons can involve the bladder, the urethra which is the tube from the bladder to the outside, or incontinence can be caused by abnormalities in the parts of the brain and spinal cord that control bladder function. Incontinence can be confused with diseases that cause a pet to urinate frequently. A physical exam and laboratory tests will help in the proper diagnosis.
Urethral Sphincter Incompetence is the most commonly diagnosed cause of urinary incontinence, and is most common in spayed bitches. This is often referred to as Reproductive Hormone Responsive Incontinence or "spay incontinence." The estrogen deficiency that occurs with a ovariohysterectomy (spay) can result in changes in the urogenital tract. Due to the lack of estrogen, the urethral sphincter may lose tone, and the urethral mucosal lining may weaken, resulting in a less tight seal to the system. Estrogen may also be tied to the normal synthesis and maintenance of collagen, a chief component of connective tissues that structurally support the urinary tract.
There are two main types of drug therapies used to treat this type of incontinence. One type are estrogens (typically DES or Premarin) which help to replace the hormones no longer produced after a spay. The other drug therapy, is Phenylpropanolamine (PPA), which is a nervous system stimulant that increases the production and release of neurotransmitters that help tighten the urethral sphincter. Because these drugs work on different mechanisms, they may even be used in combination with each other if one drug alone doesn't work. It is important to work in tandem with your vet to determine the best course of treatment, but note that drug therapy is often very successful in controlling this type of incontinence once the appropriate drug or drugs and dosages are determined.
At times, young female puppies may also exhibit signs of incontinence as they are growing. It is not uncommon for those issues to resolve themselves as the puppy matures. It is important that these structures have adequate time to mature, which is why early spays are problematic in this slow-growing and maturing breed. Therefore, it is very important that female puppies be allowed to have one heat cycle before they are spayed. This usually decreases the chance and severity of any incontinence as it gives the urethral sphincter the opportunity to mature and tighten.
Many vets will try to convince pet owners that early spay is critical in the prevention of mammary tumors. That said, we know that in this breed, urinary incontinence has a much higher incidence and chance for early onset when spays occur before the first heat. The incidence of mammary tumors in this breed, on the flip side, is quite small. Incontinence has been on the rise as a major reason Swissies are surrendered to Rescue. Please think long and hard, and speak with your breeder before allowing a vet to talk you into spaying your bitch before her first heat cycle.