Bladder stones in dogs

Bladder stones are formed when collections of minerals create rock like structures in the bladder. These stones or uroliths vary in size from single large stones to multiple smaller stones or crystals. The presence and effect of these stones or crystals in the bladder causes a disease called Urolithiasis.

What are the signs of Bladder stones?

Signs that your dog may be suffering from Urolithiasis may be primarily related to urination. There may be an increase in frequency of urination and your dog may urinate in unusual places such as in the house. You may notice your dog straining to urinate (dysuria) with small dribbles of urine rather than a normal stream. There may also be blood in the urine (haematuria). These signs are very similar to the signs of cystitis. In severe cases of canine urolithiasis your dog may become very weak and depressed, show signs of vomiting and extreme pain. Full obstructions of the urethra can occur. If left untreated these dogs are in a life threatening situation. The blockage of normal urine flow results in an accumulation of toxic waste material in the body. This can eventually lead to death.

What are the causes of Bladder stones in dogs?

There is no single cause of Canine Urolithiasis but there a number of factors which are thought to contribute to the condition. One theory about the formation of bladder stones is the Precipitation-Crystallisation Theory. This theory states that certain compounds are present in elevated levels and this causes the formation of bladder stones. These compounds can be due to abnormalities in the diet or due to some previous disease in the bladder, for instance, infection with bacteria. Once the level of these compounds exceeds threshold level the urine becomes supersaturated. The compound then precipitates and forms tiny crystals which stick together. These crystal formations grow into bladder stones.

Both males and females are affected by the condition but the narrow urethra of the male means that the disease has more serious implications and more risk of obstructions. Dogs of any age can be affected but the majority of cases are between the ages of 2 and 10 years old.
Small breeds are commonly affected, including the Welsh corgi, Pug, Lhasa Apso, Pekingese and Yorkshire Terrier. The Beagle, Dalmatian, Bulldog, Cairn Terrier and Scottish Terrier can also be affected.

High levels of some minerals in the diet can influence the formation of uroliths. Minerals such as magnesium, phosphorus and calcium. Excess protein in the diet can also increase the incidence of stone formation. Inactivity may also be a factor in the development of Urolithiasis. Dogs that don’t regularly exercise or aren’t allowed to urinate frequently may be at a greater risk.
Some believe the presence of certain compounds in the urine can precipitate the formation of crystals. Infection and the presence of bacteria are thought by some to create a focus for crystal formation.

How is Canine Urolithiasis diagnosed?

There are a variety of investigations to diagnose bladder stones and your veterinary surgeon may use a combination of these.
• Abdominal palpation- sometimes these stones are large enough to be felt through the abdominal wall.
• Urinalysis- spinning down samples of urine can often help identify crystals. Bacterial culture can also identify the presence of infection.
• Radiography- some types of uroliths show up on x-ray films, sometimes a contrast medium is injected into the bladder to identify the stones
• Ultrasound- experienced veterinarians can identify the presence of stones in the bladder from a bladder scan.

What is the treatment?

For dogs that have an obstruction, the first and most important stage of treatment is to remove the blockage. This may be achieved by catheterisation of the dog’s urethra and bladder. For severe cases of Urolithiasis, surgery may be the only option and prompt removal of the bladder stones and potential obstructions is indicated. The stones removed can then be sent away for analysis to decide on the best treatment options.

For minor cases of Urolithiasis or where only very small stones or crystals are present, treatment can sometimes be aimed at dissolving the stones present through alterations of the diet. A prescription diet may be available for your dog’s particular type of stones or you may be able to feed a diet with reduced protein and mineral content. Sometimes a diet additive may be recommended to you which may change conditions in the bladder and stop the formation of particular stones.

When feeding a prescription diet it is vital that your dog isn’t allowed access to any other types of food as this will make the diet ineffective. It is extremely important for your veterinarian to identify which stone is present since this will determine which treatment options are available to you. It is also important to remember that not all formations of uroliths are only composed of one specific stone. Occasionally there are combinations of different crystals present.

How can I prevent this in the future?

For dogs that have had surgery, you must provide appropriate post-operative care. Dogs treated for Urolithiasis can often have a repeat of the disease without sufficient preventative measures. If your dog has been prescribed a special diet it is essential that this diet is the only food your dog has, any other additions to the diet may make the special diet ineffective. Promoting water intake can help recurrence of the condition and your dog should always have access to clean fresh water. Occasional urine samples may be requested by your vet to monitor the disease and enable an early warning method for the formation of crystals in the urine.

Disclaimer

This pet health article is for reference only.

If your pet is showing any symptoms or distress, and you suspect your pet is ill CONTACT YOUR VET IMMEDIATELY.