The crystals are a result of letting a urinary tract infection go too long. The reason a ultrasound was mentioned was to look for stones (another product of leaving a urinary tract infection untreated). If this is a one time occurence then most likely the meds will clear it up. If UTI's become a chronic problem you will have to keep a close eye on her and have her tested regularly so it doesn't progress to crystals and stones. You can buy urine test strips online so you can test her urine monthly or so yourself. These are the same strips used by vets.
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