Aloha! You're speaking to Dr. Michael Salkin
It's important to recognize that crystalluria (crystals in the urine) is usually clinically insignificant but can be important in limited situations. Crystal type is important in association with current or prior occurrence of calculi (stones) and when one suspects a portosystemic shunt, ethylene glycol toxicity or melamine intoxication. Whenever crystalluria is considered significant, it's important to examine fresh, unrefrigerated urine specimens.
Detection of ammonium urate crystals in dog breeds other than Dalmatians
and English bulldogs
may suggest hepatic insufficiency (i.e., portosystemic shunt). Calcium oxalate monohydrate crystals in animals in acute renal failure suggest ethylene glycol ingestion - not a consideration here. The presence of cystine crystals indicates cystinuria, which places a dog at risk for cystine calculi. Do you know which type of crystal(s) has been seen in Molly?
Crystalluria often causes concern about urolithiasis but crystalluria must never be the sole criterion for assessment of stone composition when uroliths are present and dogs with crystalluria don't necessarily form uroliths and finding crystalluria isn't necessarily an indication for treatment. For example, dogs normally excrete a large amount of ammonium magnesium phosphate (struvite). With urine pH greater than 6.5, this normal excretion begins to become visible as struvite crystals. The higher the urine pH, the more crystals become evident. Struvite crystalluria is normal in most dogs. Urolithiasis becomes a risk when urine pH remains consistently alkaline, usually from infection with urease-producing bacteria - which has been ruled out.
All medical etiologies for Molly's crystalluria appear to have been ruled out. Unless Molly is forming one of the more unusual crystals as noted above, behavioral inappropriate urination should be my working diagnosis and "potty retraining" considered at this time. Please respond with further questions or concerns if you wish.