Kidney Stones (Struvite) in Dogs

By PetMD Editorial on Jul. 2, 2008

Urolithiasis, Struvite

Urolithiasis, Struvite in Dogs

Urolithiasis is the medical term referring to the presence of stones in the kidneys, bladder or anywhere in the urinary tract. Struvite -- the primary composition of these stones -- is a material that is comprised of magnesium, ammonium and phosphate. The stones are more common in female dogs than in male dogs, and typically in animals that are mid-range in years (six to seven years of age). Struvite stones account for more than one-third of all stones found in the urinary tracts of dogs.

Symptoms and Types

While some dogs may not display any symptoms, others have urinary problems such as:

Abnormal urine stream
Difficulty urinating (dysuria)
Frequent urination
Blood in the urine (hematuria)
Cloudy urine
Increased thirst

Moreover, increased thirst (polydipsia) is usually associated with stones present in the kidneys. If there is a substantial amount of inflammation, the bladder could be enlarged. Sometimes, you'll be able to feel the actual stones through the skin with your hand.

Causes

There are several known risk factors including high levels of steroids, an abnormal retention of urine, and extremely non-acidic (alkaline) urine. These type of stones are also more common after urinary tract infections or disorders. Some breeds of dogs are more prone to stuvite stones, including:

Miniature Schnauzers
Shih Tzus, Bichon Frises
Miniature Poodles
Cocker Spaniels and Lhasa Apsos

Diagnosis

X-rays and ultrasounds are usually used to determine the size, shape and location of the stones, and to properly assess treatment options.

Treatment

Dietary management, in association with antibiotic treatment, has been effective at dissolving struvite stones. If dietary management is used, follow it explicitly and eliminate other foods and treats until the animal has fully recovered.

The process of dissolving stones usually takes between two weeks and up to seven months. If the stones do not begin to dissolve after a few weeks, surgery may be necessary.