Diet for dogs with urate stones

A number of issues and diseases can affect your dog’s urinary system, and among these are several types of uroliths, commonly referred to as ‘stones’. They develop in the urinary tract – primarily the bladder – of some dogs. In this blog, we will focus on just one type of urolith – urate stones, also known as uric acid stones or bladder stones (urate and uric acid are different terms for the same thing). For reference, other common types are calcium oxalate stones and struvite stones.

Some breeds are more susceptible to these stones than others. Here’s what you need to know about protecting your dog from urate stones.

Which dogs are susceptible?

Generally speaking, there are two types of dogs that are prone to developing urate stones: those with liver shunts and those with a genetic predisposition.

A liver shunt is a condition where blood flow to and through the liver is compromised. This prevents the by-products of digestion and other wastes from being processed properly. It also prevents the absorption of nutrients that would normally occur in the liver.

A genetic predisposition means that, under the right conditions, a dog breed is more likely to develop a disease. Dalmatian dogs have a predisposition to urate stones due to a metabolic defect inherent in this breed, causing high amounts or uric acid in the urine. Urate stones are also much more common in male Dalmatians than female dogs.

What are uric acid stones and where do they come from?

Uric acid stones are formed from foods that contain molecules called purines. These substances are found in high concentrations in common protein. Some proteins contain more purines than others. For example, organ meats have the highest levels of purines, whereas vegetable and dairy based proteins have the lowest.

In most dogs, the purines from food are broken down into uric acids in the liver. This is then converted into a water-soluble substance, something that will dissolve in water, called allantoin. The allantoin then passes from the kidneys to the bladder to be excreted in urine.

I’m a visual person, so I made a little diagram.

The Dalmatian is unique among dogs since the last step doesn’t take place. The purines are broken down into uric acid, but the liver isn’t able to convert it into allantoin. This means that Dalmatians must excrete uric acid in their urine without the last conversion.

Because uric acid isn’t water soluble, it can crystallise. Consequently, these uric acid crystals accumulate in the kidneys and move to the bladder where lots of these crystals can come together to form a stone. Urate stones can be a medical emergency for your dog because they can grow large enough to block the flow of urine completely. If your dog is unable to pass urine, it is a life-threatening situation.

In case you are curious, this is an example of how urate stones would look like when removed.

Stones: the signs and symptoms

Urate crystals can be very irritating to a dog’s kidneys and bladder and can trigger urinary tract infections. Symptoms of possible uric acid crystals or stones and signs to look out for include:

● Straining and/or discomfort during urination
● Blood in the urine
● Cloudy urine
● Seeing gritty material in the dog’s urine
● Passing only small amounts of urine
● Abnormal urine streams
● Urine leakage accidents around your home

Hopefully, this is an issue that will never happen but if your dog is a Dalmatian or mix, and you suspect crystals or stones, it’s important to ask your veterinarian to collect a urine sample immediately to check for signs of a problem.

How are urate stones diagnosed?

In some cases, your vet may be able to feel urate stones in the bladder. However, some stones are too small to be felt this way and unfortunately, urate bladder stones are often radiolucent, meaning that they are not always visible on X-rays. This means that your vet will need to perform other imaging studies, such as a bladder ultrasound or a contrast radiographic study, a specialised technique that uses dye to outline the stones in the bladder, in order to see the stones.

What is the treatment for dogs with uric acid stones?

Urate stones cannot be left untreated. There are two main reasons for this: the presence of stones in the bladder can damage its inner layer and create pain, inflammation and predispose your dog to bacterial infections; and the risk of completely blocking the urethra. Again, this is an emergency and can be life-threatening.

If your dog is unable to urinate because of a blockage, surgery is often required. Medications are sometimes prescribed to dissolve the stones; this method takes about four weeks to completely resolve the condition. There are also more recent techniques that use high ultrasonic waves to dissolve the stones into small fragments that can be flushed out of the bladder.

How can I prevent and monitor my dog for the recurrence of urate stones?

Once a dog has had urate stones that have been cleared, the focus turns to prevention and monitoring.

To monitor for the recurrence of stones it is important you work with your veterinarian to develop a regular plan for urine testing and either X-rays or ultrasound examination to look for new stones while they are small enough that they may be able to be treated without surgery.

The key part of the prevention plan is diet modifications. I have been working with Dalmatians for 10+ years now and never had an issue with stone formation or recurrence once the right diet is being fed. The trouble is that some owners don’t want to accept what the right diet is because it’s a vegetarian diet.

Wait. What? …I hear you ask. Okay, let me explain.

Nutritional management of uric acid stones

The main dietary strategies to reduce the likelihood of urate stone formation is to reduce your dog’s intake of purines. Without the purines that trigger urate stone formation, even dogs with a genetic predisposition can lead normal lives.

Foods that are high in purines include seafood, poultry and red meats, particularly organ meat such as kidneys and liver. Dairy products, tofu, eggs, most vegetables, and fruits are considered virtually purine-free. For this reason, a low purine diet will typically centre around vegetarian food ingredients.

Keeping your dog well hydrated is also vital. This dilutes their urine, which in turn dilutes the levels of chemicals that promote stone formation, and so decreases the chance of your dog developing bladder stones.

You can help your dog drink more water by placing a few bowls of fresh water in different locations around the house. Always make sure the water is fresh and that you change it regularly. In the ideal world we are aiming to maintain urine specific gravity <1.020.

Some Dalmatian owners believe that giving their dogs who are prone to forming urate stone only mineral-free distilled water has helped prevent more stones from forming. No scientific evidence for this exists.

Never add vitamin C to the diet of a stone forming dog, as it’s likely to acidify the urine. Brewer’s yeast is another popular supplement that should be avoided due to its very high purine content.

There are a few veterinary prescription diets designed to reduce the likelihood of urate stones, but you can also prepare your dog’s food at home using the same high-quality ingredients that you eat.

There are several health benefits of making your dog’s food at home. Because most high protein foods are also high in purines, commercial diets are often low in protein. However, it is not the quantity of protein that causes urate problems, it’s the type of protein. By feeding a homemade diet you can easily choose and prepare food ingredients that are high in protein and low in low purines such as eggs, cheese and yogurt.

By feeding your dog a home-prepared diet rather than a dry kibble diet, you also increase the amount of water they are drinking. And as mentioned above, increased water consumption makes urine more dilute and can help prevent stones forming.

Take away for Dalmatian owners 

Uric acid stones can be very painful. But the good news is that sticking to specific dietary recommendations and monitoring your dog’s urine can reduce the chances of them developing or coming back in dogs who have previously had them.

Make sure your dog always has access to plenty of fresh water. Keeping them hydrated keeps the urine from becoming concentrated and makes crystals less likely to form

If you’d like to try cooking for your dog, it is vital you get your recipe from a qualified nutritionist to ensure that the diet is meeting all your dog’s nutritional needs, in particulate to ensure that the diet meets the body’s requirements of amino acids.

Say hello to Happy!

His owner knew the importance of immediate diet changes when large quantities of crystals were found in his urine. She got in contact and Happy was put on a vegetarian homemade diet. One month on, his urinalysis came back clean! This beautiful puppy is very lucky to have an owner who acted quickly on his behalf and I was very lucky to get to work with both of them.