Bladder Stones in Dogs
Definition of Bladder Stones
Bladder stones, also called urinary calculi or uroliths, are abnormal accumulations of minerals and other things in the urinary bladder. Canine urine contains a number of substances that normally remain dissolved. When urine gets too concentrated, these dissolved substances can crystalize. Common urinary crystals in dogs are struvite, calcium oxalate, urate, calcium phosphate, silicate and cystine. Over time, crystals can combine with bacteria and other material to form bladder stones. Diet, hydration, urine pH, bladder infections, medications, conformation of urinary structures and genetics all may influence stone formation. Bladder stones are common, especially in older dogs and males. They cause problems when they damage the bladder lining or block the passageway to the outside world, called the urethra. This causes urine to back up, which is extremely painful, can cause the bladder to rupture and is potentially fatal. It’s important for owners to recognize the signs of bladder stone obstructions, so that they can get their dog to a veterinarian as quickly as possible.
Canine urine contains a number of different minerals, or salts, that normally remain dissolved in fluid. When the urine becomes too concentrated, or “supersaturated,” these dissolved salts can precipitate out of the fluid to form solids in the form of crystals. These crystals can damage the lining of the urinary tract, causing blood in the urine (hematuria), and can predispose affected dogs to developing bacterial urinary tract infections. Over time, the mineral crystals can aggregate
Many affected dogs show no outward signs of discomfort from urinary tract crystals or stones. The signs become obvious when the crystals damage the urinary tract lining, or when one or more stones block the ureters or urethra, causing acute and extreme pain and predisposing the dog to bladder rupture, which is a very serious condition. Signs that owners might notice of urinary tract stones include:Many of these signs mimic those of other conditions,
Canine stones somewhere in the urinary tract are typically diagnosed based upon the dog’s history as told by the owner, a complete physical examination, a urinalysis and abdominal radiographs (x-rays). Urine culture and sensitivity are useful where bacterial infection is suspected. Abdominal ultrasonography can also be helpful in arriving at a diagnosis. Another diagnostic tool available to veterinarians, especially in male dogs suspected of having a urinary blockage, is attempted passage of a urinary catheter
Depending upon their composition, stones in the urinary tract can be either dissolved with diet and medical management or removed surgically. The best treatment option is to detect and remove the stones before they cause a physical blockage. Once obstruction occurs, mechanical removal of stones is almost always necessary.Sometimes, urinary stones can be removed with a nonsurgical procedure called urohydropropulsion. This is more commonly done in female dogs, based on their anatomical differences from males.