Urolithiasis is a disease characterized by the formation of stones, also called urolith or calculi, within the parts of the urinary system including the kidneys, ureter, urinary bladder or the urethra. Among these sites, it is in the urinary bladder where the formation of uroliths commonly takes place.
When stones or uroliths are present within the urinary tract passages, irritation can occur resulting in the occurrence of adverse effects including changes in the anatomical structure of the important parts of the urinary system, presence of blood in the urine, and the pain during urination. More serious cases often result when the stones block—partially or completely—the flow of urine making urination difficult and even impossible.
High levels of certain minerals in the urine often predispose the formation of urinary stones or calculi. A change in the urine pH accompanied by an increased urine concentration and the presence or absence of inhibitors of crystal formation often creates a favorable environment for the oversaturation of minerals.
Other important factors which have been implicated in the formation of uroliths or stones include your dog’s diet, amount of water intake, an altered metabolism of urate, or high concentrations of blood calcium.
There are also hereditary health conditions which can predispose Urolithiasis. Congenital conditions that result in the abnormal transport of cystine, an amino acid, in the kidney tubules or a defect in the circulation of blood within the liver often pave the way for the formation of uroliths.
There are also specific infections caused by bacteria which can predispose the formation of stones in the urinary tract.
Urinary calculi are often identified based on the predominant mineral that each is composed of. Cystine calculi are made up of the amino acid, cystine. There are also silica calculi, calcium oxalate calculi, urate calculi, and struvite which are made up of magnesium ammonium sulphate.
In some dog breeds, genes may dictate the type of urinary calculi which can be formed. Oxalate stones and Struvite are more common in Bichon Frise and Miniature Schnauzers. Dalmatians and English Bulldogs are prone to having urate stones while cystine stones are common in Newfoundlands. Oxalate stones are common in Lhasa Apsos.
The signs manifested by a dog with Urolithiasis will often depend on site of the calculi within the urinary tract, its size and physical appearance, number of stones present, and if there is the presence of a concurrent bacterial infection within the urinary tract.
Your vet will get a comprehensive medical history and conduct a thorough physical exam, abdominal x-rays, and urinalysis. These diagnostic tools will help establish the presence of stones and help identify them. Other tests which may be recommended include urine culture, complete blood count (CBC), ultrasound of the abdomen, kidney function test, bacterial sensitivity testing, and analysis of the stone composition.
The course of therapy is aimed at treating the existing infection, if present, with the best antibiotic of choice. Surgery may be recommended in order to remove the stones. Since there is a possibility that Urolithiasis can reoccur if the root cause is not corrected, an analysis of its contents should be made.