The ins and outs of how to care for a cat suffering from stones.

A bladder stone, or urolith, develops when mineral salts in urine combine and harden. Most stones occur in the bladder and urethra, but occasionally stones form in the kidneys and ureters, the tubes that carry urine from the kidneys to the bladder. Cats may develop one or more large or small stones. The five main types of stones that affect pets are struvite, calcium oxalate, urate, cystine, and silicate.

Risk Factors and Detection
Bladder stones affect cats of any age and breed, but certain stones tend to affect specific breeds. Calcium oxalate stones, for example, affect Himalayan and Persian cats, while cystine stones affect Siamese cats and domestic shorthair cats.

Cats suffering feline lower urinary tract disease can develop struvite stones. Other risk factors include medications or metabolic diseases that cause increased mineral-salt concentrations in the urine. Urine retention and anatomic abnormalities of the bladder also can contribute to bladder stone formation.

Signs of a bladder stone include the following:

• vocalizing during urination
• painful urination
• bloody urine
• frequent attempts to urinate
• straining to urinate
• dribbling when urinating
• lethargy
• appetite loss
• inability to urinate

The last three signs may indicate a bladder stone is completely obstructing urine flow. This condition is life-threatening, so take your cat to the veterinarian immediately. Male cats are prone to this problem because of their long, narrow lower urinary tract.

Your veterinarian will perform a complete physical examination and may use blood tests, X-rays, ultrasound, urinalysis, bacterial culture and sensitivity testing, and stone analysis to diagnose the presence and type of bladder stone, as well as any underlying metabolic disease. If your pet passes a stone while urinating, save it. Your veterinarian will have its mineral content analyzed before choosing a treatment.

Prevention and Treatment
Fresh water, a clean litter box, frequent bathroom breaks, and avoiding obesity reduces your cats risk of bladder stone development. If your pet develops a urinary tract infection, seek veterinary care and complete all antibiotic treatments.

When treating bladder stones, your veterinarians goals are to relieve any urinary obstruction, treat any infection, and dissolve or remove the stones. To remove a blockage, your veterinarian may use a urinary catheter or a cystoscope, a special scope designed for evaluating the bladder. Other treatments include surgery or urohydropropulsion, in which your veterinarian uses a catheter and fluid to flush out the stone. If the obstruction causes other illness, such as metabolic abnormalities, your cat may need intravenous fluids and hospitalization.

Different types of bladder stones require different treatments. Struvite, urate, and cystine stones respond well to medical dissolution. Depending on the type of stone, your veterinarian may use a special diet and possibly medication to dissolve it. The goals of this treatment are to decrease the concentration of stone-forming salts in the urine, increase the solubility of those salts by altering the urines pH, and increase urine volume.

Calcium oxalate and silicate stones are harder to treat and often require surgery. Your cat also may need surgery to relieve an obstruction, to remove stones that dont respond to medical dissolution, or to correct anatomic abnormalities of the bladder that contribute to stone formation. Veterinarians prefer surgery when medical dissolution is inadvisable because of other medical conditions.

Prognosis
Dissolving bladder stones with a special diet can take a few weeks to a few months. During this time, dont vary your cats diet, or treatment will be ineffective. Your pet will need follow-up urinalyses, bacterial cultures, and X-rays to ensure complete dissolution. Bladder stones are likelier to recur in pets with metabolic disorders or a hereditary predisposition. But in many cases, special diets and medications that alter urine acidity can prevent recurrence.

Pets who undergo surgery generally recover without problems, but they also require preventive care to halt recurrence.