While not as common as bladder stones, kidney stones, also known as renal calculi or nephroliths, are mineral deposits that can form in the kidneys of dogs. These stones can vary in size, shape, and composition. Kidney stones can cause discomfort, pain, and potentially more severe health issues if left untreated.

Kidney stones are frequently produced as a result of a urinary tract imbalance. The most frequent forms of kidney are calcium oxalate and struvite stones, but there are also magnesium, ammonium, and phosphate stones.

Kidney stones are solid accumulations of minerals and other substances that form within the urinary tract, including the kidneys and bladder. The exact cause of kidney stones can vary depending on the type of stones that form.

A dog's urine should be slightly acidic and contain dissolved mineral compounds in its natural state. Mineral salts remain in solution if the urine is dilute and at the correct pH. Salt crystals will settle and form stones if the pH of the urine becomes excessively acidic or alkaline or if the urine becomes too concentrated.

An imbalance in the levels of minerals, such as calcium, oxalate, and struvite, in the dog's urine can contribute to the formation of kidney stones. Feeding your dog a species-appropriate fresh food diet that is nutritionally balanced with a variety of whole foods is essential to maintain the correct balance of nutrients. However, dogs at a higher risk for kidney stones require diet alterations. 

Several dog breeds are prone to kidney and bladder stone formation, including Dalmatians, Miniature Schnauzers, Yorkshire Terriers, Bichon Frises, Cocker Spaniels, English Bulldogs, Lhasa Apsos, and Shih Tzus. 

Dalmatians are well-known for their susceptibility to urate stones. These stones form when there's an accumulation of uric acid in the urine. Dalmatians have a genetic defect that affects the metabolism of purines, leading to elevated uric acid levels.

Miniature Schnauzers, Yorkshire Terriers, English Bulldogs, and Lhasa Apsos are prone to developing calcium oxalate stones. These stones comprise calcium and oxalate, and breed-related factors may contribute to their formation.

Bichon Frises are known to be prone to struvite stones as well. They are also predisposed to urinary tract infections.

Cocker Spaniels are susceptible to struvite and calcium oxalate stones. Breed-related factors and genetics may play a role in their stone formation.

Insufficient water intake can lead to concentrated urine, which may facilitate the crystallization of minerals and the formation of stones. Adequate hydration helps to prevent the crystals that form into stones from concentrating. You must ensure that your dog stays well hydrated. You can entice your dog to drink more fluids by adding bone broth to her meals.

Medical conditions can be a cause of kidney stone formation. Some types of kidney stones, particularly struvite stones, can form due to urinary tract infections. Bacterial infections in the urinary tract can create an environment conducive to stone formation. Dogs with hyperparathyroidism (excessive parathyroid hormone) have altered mineral metabolism, increasing the risk of stone formation.

Kidney stones can cause a range of clinical signs in dogs. The signs can vary depending on the size, location, type of kidney stones, and the level of obstruction or irritation they cause within the urinary tract.

Urinary changes are likely to be the most obvious signs of kidney stones. Your dog may have an increased frequency of urination, difficulty or straining to urinate, blood in the urine (hematuria), and discolored urine (pink, brown, or cloudy).

Other noticeable signs will be changes in behavior, gastrointestinal disturbances, fever, and weight loss. Kidney stones are painful. Dogs will display signs of pain through restlessness, shifting their body position to get comfortable, and excessive licking or chewing at the genital area.

Behavioral changes can also indicate pain. Your dog may display increased agitation or irritability. Changes in activity level include lethargy or restlessness.

Vomiting, especially if the stone causes partial urinary tract obstruction, is a common sign of a kidney stone. Your dog may exhibit a decrease in appetite but an increase in thirst. Weight loss is commonly associated with chronic kidney stones. 

Persistent urinary tract infections (UTIs) are common when your dog has kidney stones. Fever will be seen with the development of UTIs. 

Kidney stones must be closely monitored. Although a kidney stone that allows urine to pass through usually will not be treated, it will be monitored to ensure it does not create any complications. A ureterolith is formed when a stone grows larger or when bits of the stone break off and become lodged in the ureter. It is pretty uncomfortable for your dog.

The kidney may also be harmed as a result of the process. If this happens in both kidneys, the severity of the problem increases dramatically, making clinical signs worse. A urinary blockage is life-threatening and requires prompt medical attention.

Diagnosing kidney stones in dogs involves a combination of clinical assessment, diagnostic tests, and imaging studies. If you suspect that your dog might have kidney stones, it is essential to consult a veterinarian for a proper diagnosis and appropriate treatment.

The veterinarian will start by conducting a thorough physical examination of your dog. They will ask about any signs you have noticed and gather information about your dog's medical history.

Laboratory tests will include a urinalysis, complete blood count, and serum biochemistry panel to assess your dog’s overall health.  A urinalysis involves analyzing your dog's urine to look for signs of kidney stones, such as the presence of crystals, blood, or abnormal pH levels. It provides valuable information about the urinary tract health.

The blood work assesses kidney function and overall health. Kidney stones can obstruct the flow of urine and impair kidney function. As a result, levels of BUN and creatinine may increase in the blood due to reduced filtration and excretion by the kidneys. Kidney stones can also affect the balance of electrolytes such as potassium, sodium, and calcium. These electrolyte imbalances would be reflected in blood work.

Kidney stones can create pockets where bacteria grow, increasing the risk of urinary tract infections. Blood work might show elevated white blood cell counts and changes in blood parameters related to inflammation in the presence of a UTI. Chronic inflammation or infections caused by kidney stones can affect red and white blood cell counts, leading to changes in blood values.

Diagnostic imaging, such as radiographs, ultrasounds, or CT scans, may be used to detect the presence of mineralized stones in the kidneys, urinary bladder, and other parts of the urinary tract. Ultrasound imaging provides a detailed view of the urinary tract, including the kidneys and bladder, while more advanced imaging techniques such as contrast radiography or computed tomography (CT) scans might be recommended to get a clearer picture of the stones and their impact on the urinary tract.

The treatment of kidney stones in dogs depends on various factors, including the size, type, and location of the stones, the presence of any underlying medical conditions, and the dog's overall health.

Medical management may include fluid therapy if your dog is dehydrated, antibiotic therapy for underlying UTIs, or lithotripsy. In some cases, shock wave lithotripsy might break up larger kidney stones into smaller fragments that can easily pass through the urinary tract.

Surgical removal might be necessary for larger stones that cannot be managed with conservative measures. Cystoscopy or percutaneous nephrolithotomy procedures might be used to remove or break down stones.

Regardless of the treatment approach, regular veterinary check-ups and monitoring are essential to assess the progress of the treatment and make adjustments as needed.

Kidney stones can cause complications if not properly managed.

Preventing recurrence is also a key aspect of managing kidney stones. This might involve ongoing dietary management, maintaining proper hydration, and regular veterinary check-ups to monitor the dog's urinary health.

Dietary Management for Dogs with Kidney Stones 

Dietary requirements for your dog will depend on the type of stone in the kidney. 

The goal is to prevent further stone formation, dissolve existing stones if possible, and manage the underlying causes. 

For dogs with calcium oxalate stones, dietary strategies focus on reducing dietary oxalate intake and promoting alkaline urine (pH greater than 7). Low oxalate foods include: 

Meats: Beef, chicken, turkey, organ meats, clams, fish, and eggs. 

Fruits: Apples, pears, watermelon, bananas, and pineapple.

Vegetables: Broccoli, Brussels sprouts, asparagus, cabbage, cauliflower, cucumber, and green left veggies.

Other products: Mushrooms, parsley, garlic, ginger, and basil.

Foods that contain high levels of oxalates include spinach, rhubarb, beet greens, Swiss chard, soybeans, almonds, cashews, peanuts, tea (black tea and green tea), berries (such as raspberries and strawberries), and kiwis. Avoid feeding any of these foods to your dog if calcium oxalate stones have been diagnosed.

Because the calcium oxalate stones form in acidic urine, one treatment and prevention tactic is to alkalize the urine. Foods that promote alkaline urine include: 

Vegetables: Most vegetables have an alkalizing effect on urine. Examples include carrots, sweet potatoes, broccoli, kale, and cucumbers.

Fruits: Some fruits have an alkalizing effect on urine, including bananas, watermelons, and cantaloupes.

Herbal Supplements: Certain herbal supplements, such as parsley, may help promote alkalinity in urine. 

Water: Ensuring your dog is adequately hydrated with clean, fresh water can help maintain urine alkalinity.

Struvite stones, composed primarily of magnesium, ammonium, and phosphate crystals, typically form in alkaline urine. Struvite stones are often associated with urinary tract infections caused by specific bacteria, such as Proteus or Staphylococcus. The bacteria produce an enzyme called urease, which hydrolyzes urea in urine and forms ammonia. The increased alkalinity and elevated ammonia levels in the urine create an environment favorable for struvite crystal formation.

The treatment goals are to dissolve the stones, eliminate underlying urinary tract infections, and prevent stone recurrence. You want to feed fresh foods that promote urinary acidification, antimicrobial therapy to treat infections, and increased water consumption to maintain dilute urine. 

Dissolution of the stones may be possible if an existing urinary tract infection is treated and dietary changes are implemented. The optimal diet for dissolving struvite stones is rich in high-quality animal fat. If your dog is new to raw feeding, you must switch slowly to prevent a bout of acute pancreatitis. 

Adding apple cider vinegar (ACV) can help acidify your dog’s urine and prevent stones from forming. The optimal ACV is raw, organic, and unfiltered. You can mix it into your dog’s meal or with water, if she will drink it, at the following doses:

Herbs and Whole Food Supplements to Treat Kidney Stones

Some herbs that are commonly suggested for supporting kidney health in dogs include:

Dandelion (Taraxacum officinale): Dandelion is believed to have diuretic properties that may help increase urine production and promote the elimination of waste from the kidneys.

Nettle (Urtica dioica): Nettle has potential diuretic and anti-inflammatory effects, which could aid in supporting kidney function.

Cranberry (Vaccinium macrocarpon): Cranberry is sometimes recommended for urinary tract health. It may help prevent urinary tract infections and promote a healthy urinary environment.

While not as common as <a href="https://feedreal.com/articles/what-to-feed-a-dog-with-bladder-stones">bladder stones</a>, kidney stones, also known as renal calculi or nephroliths, are mineral deposits that can form in the kidneys of dogs. These stones can vary in size, shape, and composition. Kidney stones can cause discomfort, pain, and potentially more severe health issues if left untreated.

What to Feed a Dog with Kidney Stones

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