Urolithiasis.

Uroliths occur commonly in the bladder and/or urethra of dogs and cats and can be life-threatening if urethral obstruction occurs. The majority of uroliths are composed of struvite or calcium oxalate; however, other minerals such as urate and cystine occur. Uroliths may be composed of more than one mineral. Some uroliths are amenable to medical dissolution (eg, struvite, urate, and cystine) while others (eg, calcium oxalate) are not. Medical management involves decreasing urine saturation for the minerals that form uroliths.