The causes of nephroliths may be related to lithogenic diets, genetic predisposition (e.g. Dalmatians, English Bulldog, Russian Black Terrier, Large Munsterlander) but has also been reported in association with renal dysplasia and some drugs such as ceftriaxone.
Crystals usually begin to form in the nephron and grow in the collecting ducts after aggregation with other large crystals. Crystal deposits in the collecting ducts near the papillary surface, when exposed to the renal pelvic urine, become nidi for the development of kidney stones.
However, it is not uncommon for dogs to have nephrolithiasis, ureterolithiasis and urolithiasis. Bilateral nephroliths also occur but are more rare in dogs.
In dogs, the majority remain static in size and may be undetected for years without clinical symptoms. Some dogs present with acute renal injury characterized by renal pain, fever, anorexia and vomiting. In some dogs, this may be due to perinephric [[abscess] formation.
Diagnosis is based on presenting clinical signs such as renal pain, blood tests, imaging studies (radiography, ultrasonography and CT scans) as well as excretory urography.
Treatment of nephrolithiasis in most canine cases involves a nephrotomy, pyelotomy or salvage ureteronephrectomy. Surgical intervention is indicated in cases where there is evidence for obstruction, recurrent infection, progressive nephrolith enlargement, presence of clinical signs (renal pain), and patients with nephroliths in a solitary functional kidney.
In specialized clinics, alternative treatments would include extracorporeal shock-wave lithotripsy (usually reserved for smaller nephroliths) or percutaneous nephrolithotomy.
Special medical dissolution diets containing amino acid supplements have been reported but are not commonly employed.
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