4187. Calcium oxalate crystals and stones in dogs. What to do?

Current research indicates that urine high in calcium, citrates, or oxalates and is acidic predisposes a pet to developing calcium oxalate urinary crystals and stones. Recent studies have shown diets that cause high urine acidity (urine pH less than 6.5) may predispose dogs to develop this type of bladder stone.

In dogs, calcium oxalate bladder stones are the second most common type of stone, second only to struvite stones. Both form 85% of urinary stones.

The exact cause of calcium oxalate bladder stones is complex and poorly understood at this time.

 

The signs of bladder stones are very similar to the signs of an uncomplicated bladder infection or cystitis. The most common signs that a dog has bladder stones are hematuria (blood in the urine) and dysuria (straining to urinate).

 

 

DIAGNOSIS:
1. Stone analysis is the definitive analysis. 

If the dog has acidic urine and calcium oxalate crystals, a presumptive analysis of calcium oxalate urolithiasis may be made. 

X-rays may show the radio-dense stones in the bladder, kidneys or urethra. If stones are not seen on X-rays, they may be small ones. Removal by non-surgical means can be done.

 

 

TREATMENT

 There are two primary treatment strategies for treating calcium oxalate bladder stones in dogs: non-surgical removal by urohydropropulsion, and 2) surgical removal.

 
1. Surgical removal. If stones are large. Calcium oxalate stones are radio-dense and can be seen on X-rays.

2. Non-surgical - urohydropropulsion. Urinary catheter to flush out the crystals and smaller stones. Change to therapeutic diet to prevent calcium oxalate stone formation.

3. No treatment is cases of no haematuria and dysuria. For male dogs, this is risky as the small stones may lodge inside the urethra obstructing flow of urine and kidney damage due to back pressure of urine. Male dogs are prone to calcium oxalate urolithiasis.   

There are two primary treatment strategies for treating calcium oxalate bladder stones in dogs: non-surgical removal by urohydropropulsion, and 2) surgical removal.

NO TREATMENT IF NO SIGNS OF HAEMATURIA OR DYSURIA
Since calcium oxalate bladder stones are most commonly diagnosed in male dogs, and male dogs are at an increased risk of urinary obstruction due to a small stone becoming lodged in the urethra, it can be extremely risky to adopt a "wait-and- see approach".

 

 

PREVENTION: How can I prevent my dog from developing calcium oxalate bladder stones in the future?

Dogs that have developed calcium oxalate bladder stones in the past will often be fed a therapeutic diet for life. Diets that promote less-acidic and more dilute urine are recommended. Diets that may help include Royal Canin® Urinary SO, Purina® ProPlan® Veterinary Diet UR Ox™/St™, Hill's Prescription Diet® c/d® Multi-Benefit, or Rayne Clinical Nutrition Adult Health-RSS™. 

Table food may be a problem for these dogs. Most dogs should be fed a canned or wet diet to encourage water consumption. Dilute urine with a low urine specific gravity (urine specific gravity or USpG less than 1.020) is an important part of the prevention of calcium oxalate bladder stones. In certain cases, medications to lower the urinary pH such as potassium citrate may be required. 

Dogs that repeatedly develop calcium oxalate bladder stones without high blood calcium levels may benefit from hydrochlorothiazide treatment.

Dogs diagnosed with calcium oxalate stones should avoid calcium supplements unless specifically advised by your veterinarian. They should not be fed high oxalate foods such as nuts, rhubarb, beets, green beans, and spinach.

In addition, careful routine monitoring of the urine to detect any signs of bacterial infection is also recommended. 

Bladder X-rays and urinalysis will typically be performed one month after treatment and then every three to six months for the remainder of the dog's life. 

Dogs displaying any clinical signs such as frequent urination, urinating in unusual places, painful urination or the presence of blood in the urine should be evaluated immediately. Unfortunately, calcium oxalate stones have a somewhat high rate of recurrence, despite careful attention to diet and lifestyle.

 

CONCLUSION. Each case is different. Your vet will advise you.   

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Good morning. I have analysed your dog's situation and there is no need for surgical removal of the calcium oxalate stones as they are not big. They are not visible on X-rays, hence they are not big. However, I advise non-surgical flushing out the crystals using a cathether to insert into the bladder, under general anaesthesia and flush out the crystals. After that, you feed the special therapeutic diet Hills' u/d to prevent formation of calcium oxalate. CrystoPro to improve urinary health. Ensure the dog drinks more water (feeding canned u/d will be better but this is up to you as costs will be higher). Then every 3 months, please do NOT forget urine tests for next 12 months for crystals. All the best

More information at:
https://2010vets.blogspot.com/2022/07/calcium-oxalate-crystals-and-stones-in.html

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A CASE STUDY
VETERINARY ADVICE TO DOG OWNER
Dr Sing Kong Yuen, BVMS (Glasgow)

There is no need for surgical removal of the calcium oxalate stones as they are not big. They are not visible on X-rays, hence they are not big.

However, I advise non-surgical flushing out the crystals using a cathether to insert into the bladder, under general anaesthesia, to irrigate and flush out the crystals.

After that, feed the therapeutic diet Hills' u/d to prevent formation of calcium oxalate.

CrystoPro to improve urinary health.

Ensure the dog drinks more water (feeding canned u/d will be better but this is up to you as costs will be higher).

Then every 3 months, please do NOT forget urine tests for next 12 months. After that, 6-monthly urine tests. 

More information at:
https://2010vets.blogspot.com/2022/07/calcium-oxalate-crystals-and-stones-in.html