Definition of Calcium Oxalate Crystals

Calcium oxalate crystals are small crystals that form when calcium and oxalate or calcium and phosphate combine in the urine to form an insoluble complex, called a kidney stone, in the bladder. Kidney stones, one of the most common urinary tract problems in people, also can afflict dogs and cats. According to the National Kidney and Urologic Diseases Information Clearinghouse, animals and humans ingest calcium, oxalate and phosphate as a normal part of their diet, and ordinarily the chemical makeup of urine keeps these crystals from forming. In humans and animals that get kidney stones, various factors alter that chemical balance.

  1. Causes of Kidney Stones

    • Heredity plays a role in kidney stone formation. This is especially obvious in dogs and cats since certain breeds show more of a tendency to develop stones than others, according to VeterinaryPartner.com. In people, diet also contributes to stone formation in those who have a genetic propensity to develop stones. Urinary tract infections, metabolic disorders, medications, some types of surgery and certain kidney diseases also contribute to stone development, according to the National Kidney and Urologic Diseases Information Clearinghouse. Stones made of calcium oxalate crystals develop in acidic urine, while stones made of calcium phosphate develop in alkaline urine.

    Kidney Stone Symptoms

    • Often, kidney stones stay small enough to pass through the body unnoticed. When a stone gets too large, however, it creates a sharp pain and cramping as the body tries to move it through the urinary tract. Vomiting, nausea and blood in the urine may accompany the sharp pain, according to the National Kidney and Urologic Diseases Information Clearinghouse. Cats and dogs show signs of kidney stones when they urinate frequently, in small amounts, and not in their usual places, according to the Dog Health Guide. They may also vomit.

    Developing Stones

    • Men develop stones more frequently than women. In humans, according to the National Urologic and Kidney Diseases Information Clearinghouse, the incidence of kidney stones rise dramatically as men reach their 40s and continues to rise into their 70s. For women, kidney stone occurrence peaks in their 50s. Once you have had more than one stone, you have an increased chance of developing more.

    Kidney Stones in Dogs and Cats

    • Male dogs, like male humans, have a much greater susceptibility to developing calcium oxalate bladder stones than females. According to veterinarian Dr. Wendy Brooks with VeterinaryPartner.com, the breeds most likely to get these kidney or bladder stones are miniature schnauzers, Lhasa apsos, Yorkshire terriers, miniature poodles, shih tzus and Bichon frises. Cats can form several different types of crystals that create stones; however, according to the Utah Veterinary Clinics website, Himalayan cats are particularly susceptible to kidney stones made of calcium oxalate crystals.

    Avoiding Kidney Stones

    • In the past, doctors advised people who tended to develop stones to avoid calcium-rich foods and dairy products. According to the National Kidney and Urologic Diseases Information Clearinghouse, however, recent studies have shown that these foods may actually help prevent kidney stones. Diets high in animal proteins create more acidic urine, which contributes to development of calcium oxalate stones; so, decreasing meat, fish and poultry in the diet is advised. Drinking at least two quarts of water a day dilutes the urine and helps prevent stone formation, according to UroStoneCenter.com.