Urolithiasis (Urinary Stones)
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
Emergency presentation is possibleAny future inability to urinate requires immediate emergency treatment.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Urolithiasis is the formation of mineral stones within the urinary tract. In cats, stones are most commonly found in the bladder, although they can occur in the kidneys, ureters or urethra. The two major bladder-stone types are struvite and calcium oxalate, and they behave differently enough that identifying the type matters for treatment.
Bladder stones irritate the lining and may cause blood in the urine, frequent urination, straining, genital licking or urination outside the litter tray. Some stones are discovered incidentally. In male cats, a small stone or associated inflammatory material can lodge in the urethra and cause life-threatening obstruction. Stones in a ureter can obstruct urine flow from a kidney and may cause kidney injury even when lower urinary signs are absent.
Stone formation is influenced by urine chemistry, mineral concentration, water intake, diet and individual susceptibility. Bacterial infection plays a smaller role in most feline struvite stones than it does in many canine cases. Calcium oxalate stones cannot be dissolved with diet, whereas many sterile struvite bladder stones can be dissolved using an appropriate prescription diet.
Analysis of a removed stone gives the most reliable information about composition.
Because urinary signs are not specific, crystals seen in urine do not automatically prove that a stone is present, and the absence of crystals does not rule one out.
The clinical importance of a stone depends on more than its size. A small mobile stone can become dangerous if it enters the urethra, while a larger bladder stone may cause chronic irritation without obstruction. Location, composition and the cat’s anatomy all influence the urgency and treatment choice.
A cat with a previous urinary stone remains vulnerable to recurrence, making renewed straining or altered urine volume clinically important.
Screening & Early Detection
Cats showing blood in the urine, repeated straining, frequent small urinations or discomfort need veterinary assessment. A male cat making repeated attempts without producing urine should be treated as an emergency because a stone or plug may be obstructing the urethra.
Urinalysis helps evaluate urine concentration, pH, blood, inflammation and crystals. Crystals can support a diagnosis but must be interpreted carefully because they may form after a sample is collected or may not match the composition of an existing stone. Urine culture is appropriate when bacterial infection is suspected.
Imaging is central to early detection. Abdominal radiographs reveal many struvite and calcium oxalate stones, while ultrasound can identify stones that are difficult to characterise on radiographs and can assess the kidneys and ureters. Cats with recurrent stones may need repeat imaging even when symptoms improve.
Once a stone is removed, laboratory analysis should be requested whenever possible because prevention depends on its composition. There is no universal screening interval for healthy cats. Cats with previous urolithiasis are monitored according to stone type, urine findings and recurrence risk, often with periodic urinalysis and imaging.
Diagnosis usually combines urinalysis and imaging. Radiographs identify many mineral stones, while ultrasound can detect additional stones and assess the bladder and kidneys. Urine culture is used when infection is possible.
Treatment & Management
Treatment depends on stone composition, location and whether urine flow is obstructed. Many sterile struvite bladder stones can be dissolved with a prescription diet designed to alter urine chemistry. The diet must be fed exclusively and follow-up imaging is used to confirm that the stones are actually shrinking.
Calcium oxalate stones do not dissolve with diet. Bladder stones may need surgical removal or another retrieval technique, while ureteral stones can require specialist procedures if they obstruct a kidney. A urethral obstruction is an emergency requiring stabilisation and restoration of urine flow before long-term stone management begins.
Water intake is increased wherever possible using wet food, fountains and multiple water stations. Dilute urine reduces the concentration of minerals available to form new crystals. Preventive diet is selected according to the stone type rather than using a generic urinary product.
Antibiotics are used only when infection is present. After removal, stone analysis guides prevention, and periodic urinalysis and imaging are used to detect recurrence before another obstruction develops. Any future inability to urinate requires immediate emergency treatment.
Treatment decisions should be based on the whole clinical picture.
Breeds or species affected
Abyssinian
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American Bobtail
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American Curl
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American Shorthair
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American Wirehair
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Arabian Mau
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Aegean
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Australian Mist
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Balinese
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Bengal
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Birman
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Bombay
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British Longhair
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British Shorthair
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Burmese
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Burmilla
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Chartreux
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Chausie
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Colorpoint Shorthair
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Cornish Rex
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Cymric
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Devon Rex
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Domestic Longhair
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Domestic Medium Hair
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Domestic Shorthair
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Donskoy
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Egyptian Mau
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European Shorthair
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Exotic Shorthair
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Havana Brown
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Highlander
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Himalayan
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Japanese Bobtail
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Khao Manee
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Korat
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Kurilian Bobtail
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LaPerm
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Lykoi
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Maine Coon
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Manx
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Minuet
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Minskin
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Munchkin
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Nebelung
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Norwegian Forest Cat
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Ocicat
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Oriental Longhair
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Oriental Shorthair
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Persian
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Peterbald
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Pixiebob
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RagaMuffin
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Ragdoll
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Russian Blue
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Savannah
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Scottish Fold
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Scottish Straight
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Selkirk Rex
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Siamese
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Siberian
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Singapura
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Snowshoe
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Somali
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Sphynx
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Thai
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Tonkinese
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Toybob
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Toyger
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Turkish Angora
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Turkish Van
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Bambino
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Cheetoh
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Dwelf
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Elf Cat
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Genetta
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Kinkalow
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Lambkin
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Serengeti
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Skookum
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Ukrainian Levkoy
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