LOWER URINARY TRACT DISEASES in dogs can be listed in six general categories. In order of prevalence, they are:

1. Incontinence
2. Urolithiasis (stones or crystals in bladder)
3. Bacterial infection
4. Cancer
5. Trauma
6. Obstruction

The older the dog, the more likely it is to have one of these diseases. In one study of canine lower urinary tract disease, 57.4% were found in female dogs, and 42.6% in male dogs.

Incontinence

Urinary incontinence is the number one lower urinary tract disease in dogs over 7 years old. The dog's weakened urethral sphincter muscle allows urine to “leak” out. Often the dog dribbles urine without knowing it, sometimes when sleeping. The most common cause of this condition in neutered pets is a decrease in estrogen for female dogs and testosterone for male dogs. The sex hormones are essential for urethral and sphincter muscle contraction. With a decrease in these hormones, the bladder sphincter may not to close completely when the dog is at rest, thus allowing leakage. It is important to determine if the problem is truly incontinence. Incontinence can also be caused by other bladder problems, such as systemic disease that increases the need to urinate, or increased thirst along with a concurrent increase in frequency and urgency of urination. Usually a urinalysis and bloodwork will tell us. Ruling out other possibilities such as cystitis, cancer, and endocrine diseases, we then arrive at a diagnosis of incontinence. Once the diagnosis is made, treatment is straightforward with hormone replacement therapy or a drug treatment to increase the sphincter muscle contractions. The prognosis is good with hormone-dependent incontinence.

Bacterial infection

Bacterial infection is another common disease. It can show up as “incontinence,” frequent urination, increased thirst, increased licking at the vulva, and/or blood in the urine. We often see infections and crystals present together, and infections can stimulate crystal or stone development. Infections can be diagnosed with a urinalysis in which the bacteria are identified with bacterial culture and sensitivity. Antibiotics are used, based on the culture results, and sometimes we recommend changes in diet. The prognosis is good, if it is a straightforward bacterial infection, especially if a culture is done.

Urolithiasis

CANINE UROLITHS

The prevalence of urolithiasis also increases with age. Several kinds of calculi (stones) or crystals may be formed in the bladder depending on diet, infection and breed predilection (some dogs, like Bulldogs and Dalmatians, have a metabolism problem that causes calculi to form). If there are many crystals noted in the urinalysis, we will probably prescribe a diet to dissolve them. Bladder calculi can be difficult to diagnose. We usually look for them if there is bleeding or pain, or a palpable stone in the bladder. We take x-rays, but some calculi are not metallic and do not show up. To highlight and find them, we do require a special radiographic study using contrast material. Some can be dissolved by diet, but most require surgical removal. We then send them to the lab to determine how to prevent their recurrence.

Cancer

Cancer of the lower urinary tract is more frequent in female dogs.The most common is transitional cell carcinoma of the bladder. The most common in the male dog is prostatic cancer. Early detection is key to saving these dogs, while they are surgically amenable to treatment. Cancer is diagnosed when there is a history of persistent bleeding from the urinary tract, that does not respond to cystitis treatment and is not due to stones, plus x-rays (with a contrast study), ultrasound, cystoscopy or exploratory surgery.

TOP

Trauma and obstruction

Trauma and obstruction of the lower urinary tract are uncommon in older dogs, but do occur. The diagnosis is usually made through a physical exam and visualization of the trauma or obstruction. The treatment is to relieve or remove the obstruction and to repair the trauma.