Q: My Maltese dog has bladder stones and we’re told they need to be removed with surgery. But I’ve been reading things that say stones can be dissolved with a special diet or with a laser. Is surgery absolutely necessary? Also, he’s had crystals in his urine for years. Could this have been prevented?
A: Crystals are common in dogs and cats. In fact, they’re often considered normal. However, when the crystals become overly abundant, or when certain kinds of crystals are present, they may indicate the presence of disease. Moreover, some kinds of crystals can foreshadow future stone formation.
Though crystals are typically a problem confined to the urinary system, indicating infection or potentially coalescing into painful, problematic stones, some kinds of crystals can even point to disease elsewhere in the body. Liver disease, poisoning and genetic conditions can all lead to abnormal urine crystal formation.
Here’s how crystals and stones form: Remember high school chemistry? If so, you’ll recall that crystals will precipitate in solutions when there are too many molecules of a substance to remain dissolved. Urine concentration, pH and temperature are factors. Stones can form should these crystals coalesce into hard concretions. But not all crystals form stones.
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In dogs and cats, stone formation tends to happen in the bladder, not in the kidneys, as in humans. In cats, these crystals can sometimes mesh with other substances to form urethral plugs that can obstruct urination and lead to emergency situations. In dogs, we don’t see these plugs. Nonetheless, small stones can sometimes obstruct the urethra, particularly in males.
Could this have been prevented? Hard to say, but all pets with possible urinary tract infections (UTIs), as evidenced by straining, bloody urine or any kind of inappropriate urination, should have their urine microscopically evaluated for the presence or crystals. Those with certain crystals or frequent urinary symptoms should be X-rayed for the presence of stones. But this process can sometimes occur quickly and it’s not always predictable or preventable.
As to whether surgery is always necessary: To minimize discomfort in the presence of larger stones, surgery is typically elected. Dietary management, however, is usually considered crucial in preventing or delaying future stone formation. Wet diets are strongly recommended as this keeps the urine from becoming too concentrated.
As to the laser (performed at some veterinary schools): Yes, some larger dogs can be treated this way. Tiny dogs like Maltese, however, are not considered candidates.