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Bladder Stones in Dogs
Different dogs, different stones, different treatments
A dog with bladder stones just as in humans, will generally be in considerable pain. Bladder stones, medically know as "urolithiasis" are mineral deposits that initially appear as grains of sand. As more deposits form on these initial grains of sand, the grains turn into stones that can easily reach 4 inches in diameter.
Causes of Bladder Stones
The composition of bladder stones varies, with struvites (the most popular) being typically composed of magnesium, ammonium and phosphate while other stones may be composed of calcium oxalate (second most popular) cystine, calcium apatite, or ammonium urate. But what triggers their formation? The causes of bladder stones may be various. Breed predisposition seems to be a factor, however, many cases are diet related.
Bichon Frise' dogs seem to be particulary prone to Calcium Oxalate stones. Beagles, English Cocker Spaniels and Miniature Schnauzers are prone to struvites. Dalmations are prone to Ammonia Urate stones.
Diets too rich in protein may cause problems in some dogs. The break down process of protein may cause the body to produce urea which is a contributing factor in the formation of bladder stones.
The Ph of urine seems to also play a role. Struvite stones seem to prefer an alkaline Ph while Oxalate need a more acidic based Ph. Dogs normally have an acidic based Ph. Dogs presenting with the bacterial infection, cystitis usually will be prone to struvites due to an alkaline Ph.
Some medical conditions may cause bladder stones to form. For instance, the high levels of Cortisone found in dogs affected by Cushing's disease will increase the amount of calcium excreted in the urine potentially causing a calcium oxalate stone. Hypercalcemia, is another issue following the same scenario.
Medications such as steroids (Prednisone) and diuretics such as Furosemide may as well increase the levels of calcium leading to stone formations. Vitamin C and D supplementationsmay be a trigger as well.
Dogs affected by liver disease are prone to Ammonia Urate stones due to a buildup of uric acid and ammonia.
Diagnosis of Bladder Stones
Physical examination of the dog and the dog's medical history will provide some insight. A urinalysis will reveal the presence of a bacterial infection and the presence of crystals. Crystals can be found in normal dogs without bladder stone issues.
X-rays may identify the stones and their location when stones are sufficiently dense. Usually Struvites and Oxalate stones are clearly visible. If no stones are seen, yet the dog presents symptoms highly suggesting bladder stones, a contrast dye test may be required. In this case, a special dye will allow the x-rays to show the stones as white masses. Ammonium urate stones are often not visible unless via contrast dye.
Symptoms of Bladder Stones
- Straining to urinate due to the stone blocking the urine flow
- Inappropriate and frequent urination due to trouble urinating
- Bloody urine due to the stones rubbing against the delicate lining of the bladder
Treatment of Bladder Stones
If there is an underlying urinary tract infection (cystitis) treatment will consist of antibiotics. If the stones are blocking the urine flow, emergency surgery may need to be performed or simply a urinary catether may be inserted to unblock the passage. Male dogs are prone to urinary obstructions due to their narrow urethras and anatomy.
Some stones may be treated with diet changes or via surgery. Dietary changes often require special prescription diets. In the case of Struvite stones, Hills, for instance produces a special diet to combat struvites called S/D. This is a canned diet high in fat and salt of a gelatinous consistency. Usually, the struvites may dissolve within 3 months. The salt content of S/D helps dilute the urine and causes the pet to urinate more.
Calcium oxalate stones do not dissolve via diet and therefore, surgery is recommended.
While stones may be found in other locations such as in the kidneys or urethra, the bladder is the most affected area. Underlying issues may need to be solved along with treating the bladder stones. Identifying the correct type of stone is very important in order to decide the appropriate course of treatment.
At home, dogs should always have lots of fresh water available and should not be forced to keep from urinating for long periods of time. Canned food is preferable to dry because of its moisture contents. Unfortunately, some dogs may still have relapses and present stones once again, regardless of surgery, home care, medications and diet changes.