Urolithiasis in dogs

Dogs with urolithiasis have stones in their urinary tract. This could be in the kidneys, ureters, bladder or urethra. 0.3-2.8% of dogs get urolithiasis. It can happen in any dog, but it’s more common in females, certain breeds and dogs with other illnesses. Untreated urolithiasis can result in life-threatening blockages of the urinary tract.

Urolithiasis in dogs causes bladder irritation, infection and urinary tract blockages (blocked bladder). Uroliths include everything from tiny particles, like sand, to large single stones. And often both together. There are multiple treatment options, depending on the type of stone and location, but the condition often recurs. Always call a vet if your dog shows signs of difficulty or discomfort peeing or has blood in their urine.

Overview

What is urolithiasis in dogs?

Urolithiasis is the formation of hard rock-like material from minerals in urine. These minerals originally come from the food your dog eats. Normal urine contains minerals, including calcium, phosphorus, magnesium, chloride and sodium.

Bladder infections, diet, genetic (inherited) disorders, liver disease and previous bladder surgery can all trigger increased crystal formation from minerals in urine.
Crystals irritate the bladder wall, making it release thick mucus for protection.
The mucus and crystals stick together, getting bigger and harder over time to form stones.
Stones can take anything from a few weeks to months to form.
There are different types of minerals that cause different types of stones.
20-40% of dogs treated for urolithiasis suffer recurrence within 1 year, and almost 50% within 3 years.
Urolithiasis in dogs is a general term. Stones in different parts of the urinary tract also have specific names, for example, nephrolithiasis (kidney stones), cystolithiasis (bladder stones).

There are 4 types of stones in dogs:

Struvite
Calcium oxalate
Urate
Cystine


Bladder stone

Causes:

Infection – bacterial release chemicals that reduce acidity of urine, encouraging stone formation
Diet
Genetics
Foreign material in bladder (sutures from previous bladder surgery)
Lack of exercise and not drinking enough water
Certain medications – allopurinol prevents one type of stone but can trigger another in some patients

Symptoms

Symptoms of urolithiasis in dogs

The symptoms of urolithiasis in dogs will vary depending on the location of the stone(s).

Common symptoms:

Difficulty peeing – repeated squatting, passing small amounts, vocalising
Blood in urine
Becoming dull or depressed
Eating less
Vomiting
Having a tense, painful tummy
Fever

Risk

Dogs at a higher risk of urolithiasis

Belonging to certain breeds: Miniature Schnauzer, Pekingese, Yorkshire Terrier, German Shepherd, Welsh Corgi, English Bulldog, Dalmatian, Beagle, Dachshund, Basset Hound, Miniature Poodle, and Scottish Terrier
Eating an unbalanced diet: food very high in protein and certain minerals – calcium, magnesium, phosphorus
Having other illnesses: liver disease, diabetes, liver shunts
Not drinking enough water or getting enough exercise
Previously having had urolithiasis
Previous bladder surgery (possibly stone removal)

Complications of urolithiasis

Blocked bladder, especially male dogs with a narrower urethra
Burst bladder
Kidney damage, even kidney failure
Sepsis

Will my other dog(s) get urolithiasis?

Urolithiasis affects individual dogs and cannot spread between dogs or from dogs to humans. However, dogs in the same household with the same risk factors (breed, diet, etc) will have the same risk of getting the illness.

Diagnosis

How do vets diagnose urolithiasis in dogs?

To begin with, urolithiasis may look like a simple urinary tract infection. Your vet will need to do further tests to confirm the presence of urolithiasis.

Tests include:

Urine tests: testing urine components with a dipstick; looking for cells and crystals under a microscope
Abdominal palpation: vets may be able to feel larger stones in the bladder just by feeling the tummy of smaller dogs
X-ray: some stones will show up on standard x-rays or can be outlined with contrast dye
Ultrasound: urate and cystine
Blood tests: general health and specific causes of urolithiasis
Urine culture: checking which bacteria are causing any infection
Endoscopy: exploring the urinary tract with a flexible camera


Dog x-ray with bladder stones

Crystals form in urine left around for any length of time and sometimes even in fresh or refrigerated samples. Any sample you take to your vet for testing must be as fresh as possible. Finding crystals in urine is not the same as having urolithiasis. But it may confirm the need for further tests if your dog has symptoms.

Vet treatment

What’s the treatment for urolithiasis in dogs?

Some stones can be dissolved using special diets. Others are too large, undissolvable or require immediate removal after causing a blockage. All dogs with urolithiasis must be encouraged to drink more while treating the illness and to reduce the risk of it coming back.

Treatments include:

Special diets: to alter the acidity and chemical make-up of your dog’s urine; can dissolve some stones, either completely or to reduce size and number prior to surgery
Antibiotics: to treat infection associated with stones
Medicine to control acidity of urine: helps reduce stone formation or encourages dissolving

Procedures and operations:

Flushing

For small stones in the bladder and urethra
Carried out while your dog is asleep under a general anaesthetic
A catheter (narrow sterile tube) is passed through the urethra towards the bladder; the bladder is filled with sterile saline; after stirring things up a bit, the vet squeezes the bladder empty
Limited to small stones

Endoscopy (cystoscopy) removal

Usually carried out under heavy sedation or a general anaesthetic
Endoscope (camera) passed into bladder through urethra or via keyhole surgery. Individual stones picked picked up and removed in pincers or a mini ‘basket’, or flushed out of bladder
Limited to small stones

Surgery

Carried out under a general anaesthetic
An operation to open the tummy and bladder and remove stones directly
Likely option where large stones causing blockage

Stents

Stents are small mesh tubes used to hold open a vessel
Used for upper urinary tract blockages – the ureters
Placed via keyhole surgery and an endoscope from the kidney
May be passed up from the urethra in female dogs
Holds the ureter open to allow urine to get past a blockage

Laser treatment

Breaking up bladder stones using a laser
Only available in specialist hospitals
Works for all types of stones
Carried out via cystoscopy – unsuitable for small male dogs with a narrow urethra

Treatment options for types of urolithiasis

Struvite is dissolved using a special diet like Hills Prescription Diet s/d or c/d; antibiotics throughout treatment due to ongoing live bacterial release from dissolving stones; removal if large or causing blockage
Urate or Cystine: Hills Prescription Diet u/d may help to reduce size before removal
Calcium oxalate cannot be dissolved

Home treatment

How to care for a dog with urolithiasis at home

There are no home cures for urolithiasis. Dogs with stones in their urinary tracts risk developing life-threatening blockages. Male dogs and small dogs are at most immediate risk for this.

If your dog has had sedation, general anaesthesia, endoscope procedure, and/or surgery, follow your vet’s directions for their specific care.

You can help your dog’s recovery by:

Increasing water intake: continuing to encourage them to drink
Feeding the special diet as advised by your vet with no other foods or treats
Giving any medication at the times and doses prescribed by your vet

Prevention

How to prevent your dog getting urolithiasis

Some dogs have an inherited risk of stones. If we know the risks, we can ensure they have a special diet to prevent stones from forming. It’s one of the many reasons that it’s a good idea to research the breed before you bring a puppy or dog home for the first time.

General tips for reducing risks include:

Ensuring your dog always has lots of fresh water to drink
Maintaining them at a healthy body weight and condition
Keeping your dog active
Feeding a balanced, healthy diet
Ask a vet before giving your dog mineral or vitamin supplements

Preventing urolithiasis from coming back again:

Treating underlying illness
Feeding wet food and/or ideally a special prescription diet
Supplements for bladder health may help reduce the risk of stone formation
Medicine to prevent stone formation – for example, allopurinol to prevent urate stones

Always talk to your vet before giving your dog a special diet or supplements.

When to worry

Seek help from a vet immediately if your dog is: