💧 Vet Guide 2025: Bladder Stones (Struvite) in Dogs – Causes, Treatment & Prevention 🐶🦠

By Dr Duncan Houston, BVSc

🔍 What Are Struvite Stones?

Struvite bladder stones are hard mineral masses formed from magnesium, ammonium, and phosphate. In dogs, these stones are almost always caused by a urinary tract infection (UTI) with specific bacteria like Staphylococcus or Proteus species.

🧬 Who’s at Risk?

• 🐕 85% of affected dogs are female
• 🧬 High-risk breeds include Miniature Schnauzers, Shih Tzus, Yorkshire Terriers, Labrador Retrievers, and Dachshunds
• 📆 Average age of onset is just 2.9 years

📸 Common Symptoms

Dogs with bladder stones may show:

• 🚨 Straining to urinate
• 🔴 Bloody urine
• 🔁 Recurrent UTIs (especially with the same bacteria)

Some cases are asymptomatic and discovered incidentally on X-rays or ultrasound.

🔬 How Are Struvite Stones Diagnosed?

Diagnosis may include:

• 🧪 Urinalysis (to check pH and crystal type)
• 🧫 Urine culture (look for Staph or Proteus bacteria)
• 🩻 Radiographs – Struvite stones are radio-opaque and easy to detect

To confirm the stone type, it must be analyzed in a lab, usually after removal or spontaneous passage.

🧪 What Causes Struvite Stones?

The key driver is infection. Bacteria with the urease enzyme break down urea into ammonium, raising urine pH and creating the perfect environment for struvite to form. The inflammatory byproducts help bind crystals into stone.

🧬 Rare Exceptions

Struvite stones without infection are rare but can occur in:

• ⚖️ English Cocker Spaniels (genetic trait)
• 💊 Dogs on certain diuretics or antacids
• 🧬 Dogs with hyperaldosteronism

💡 Treatment Options

1. 🍽️ Dietary Dissolution

This is the treatment of choice for struvite stones. Prescription diets change urine chemistry to dissolve the stones safely inside the bladder.

• 🧪 Must be the sole diet
• 💊 Antibiotics must be continued during treatment
• 📸 Radiographs every 4–6 weeks to monitor progress

Most stones dissolve in 2–3 months. Continue the diet for one month after stones disappear to eliminate small remnants.

⚠️ Important Risks

• 🔒 Male dogs risk urethral obstruction during dissolution
• ⚠️ Emergency obstruction can be fatal without prompt intervention
• 💔 High-fat diets used in dissolution may not suit pets with pancreatitis, kidney disease, or heart problems

2. 🔪 Surgical Removal (Cystotomy)

• ✅ Fast and direct stone removal
• ⏱️ Immediate resolution
• 💉 Carries risks like anesthesia, pain, and infection

Often used if the dog is obstructed, infected, or needs a fast fix. Some stones may remain, so follow-up is important.

3. 💦 Voiding Urohydropropulsion

This involves flushing out small stones under anesthesia. The bladder is filled and emptied under pressure with the dog held vertically. It is non-invasive but only suitable for small stones in small dogs.

4. 🔬 Cystoscopic Removal or 💥 Laser Lithotripsy

Less invasive than surgery, stones can be retrieved or fragmented with a laser. Requires special equipment and usually costs more than surgery but has faster recovery.

📅 Preventing Recurrence

Prevention centers on controlling UTIs, not diet (except for rare exceptions like the English Cocker Spaniel).

Long-Term Monitoring Includes:

• 🔬 Regular urinalysis
• 🧫 Periodic urine cultures (even without symptoms)
• 🩻 Routine radiographs (every 6–12 months)

Some dogs can form new stones in as little as 2 weeks after a UTI. Prompt infection detection is key to preventing recurrence.

📌 Special Notes on Male Dogs

Male dogs are at greater risk of obstruction due to their narrow urethras. If repeated blockages occur, a urethrostomy surgery may be considered. This creates a new urinary opening before the bony urethra, allowing stones to pass more easily.

🩺 Final Thoughts from Dr Duncan Houston

Struvite bladder stones in dogs are highly treatable and often preventable. Most cases are rooted in bacterial infection, which means careful monitoring and good hygiene can dramatically reduce risk. After removal or dissolution, your vet will help set a custom plan to protect your dog from future issues. 🐾💧

📲 Concerned About Bladder Stones? Ask A Vet Now

If your dog has a history of UTIs or struvite stones, speak with a vet today. Download the Ask A Vet app to chat live with Dr Duncan Houston and our team of trusted professionals for customized advice, monitoring tips, and diet plans. 🐶💬