567 — Canine Bladder Stones: Diagnosis and Treatment

Canine Bladder Stones: Diagnosis and Treatment Dr. Marty Greer, DVM joins host Laura Reeves for a deep dive on bladder stones in dogs, how to diagnose and treat them. The following information is provided by Dr. Greer. Bladder stones are the quintessential “which came first, the chicken or the egg” question. By this, we mean that a dog can have a bladder symptoms that are caused by a bladder stone, or the bladder infection can cause bladder stones to form. Which then becomes a vicious cycle. There are two basic types of bladder stones – the first, struvite stones associated with a bladder infection or second, any of the following other bladder stones, caused by a metabolic disturbance that causes a stone to form in the urinary tract. How do bladder infections cause bladder stones? An undiagnosed, under-treated or recurrent bladder infection can lead to the development of struvite bladder stones. This is the most common type of bladder stone. Or another type of stone can cause irritation to the bladder which can cause a stone to form that is partly any of the types of stone below combined with a struvite stone. These form like a pearl in an oyster – the irritation of the infection or other stone type can cause a struvite coating on an existing bladder stone. Many metabolic stones are associated with a particular breed or disease condition causing minerals to deposit in the bladder, forming stones. These metabolic stones form with long term supersaturated minerals in the urine. With time, the crystals form which develop into a bladder stone. Other factors are the pH of the urine, inhibitors and promotors of stone formation, and macrocrystalline matrix. If something like suture is in the bladder, this can also allow a stone to form. Fortunately, most stones in the urinary tract are in the bladder itself, where they are accessible surgically. Stones in the kidney or ureter (tube from the kidney to the bladder) are not easily managed surgically or by physical removal. Stones that form in the bladder and pack together like sand in a funnel or slip from the bladder into the urethra (tube from the bladder to the outside of the body) cause urinary obstruction. This is a true medical emergency, more common in males that females due to the length and shape of the urethra, the tube from the bladder to the outside. Males have a design flaw – their urethra is more narrow and curved, causing a greater likelihood of urinary obstruction. On the other hand, females have a design flaw, a shorter wider urethra just below the rectum that allows bacteria to ascend into the bladder, increasing the risk that a female will have a bladder infection. That infection can often lead to the formation of struvite stones. Symptoms Symptoms of bladder disease can be virtually non-existent to severe. The symptoms can vary: No signs or very subtle signs of discomfort or urinary accidents. Signs of blood in the urine (often not noted until there is snow on the ground or when the urine is wiped up and blood is seen on a white towel), straining to urinate, frequency of urination, inappropriate urination, +/- fever, pain, and/or urinary incontinence. Dogs are rarely “sick” with a bladder infection – they eat, drink, and act normally other than increased trips outside or urinary accidents on the floor. If obstructed, there will be abdominal pain, vocalizing, vomiting, dehydration, depression, heartbeat irregularities, bladder distension, in advanced cases, bladder rupture, collapse and death. Blood work can show elevated BUN and creatinine, kidney values if obstructed. Blood work may show elevated calcium if calcium oxalate stones are present. Blood work may show liver dysfunction in patients with urate stones. Below is a table showing the different types of bladder stones, comparing the composition, cause, prevention and treatment...