Struvite is the most common type of bladder stone found in dogs. The stones start as crystal deposits from the fusion of magnesium and phosphates in the urine. The crystals exist naturally in the urine, and dogs pass them without issue in most cases. However, supersaturated urine, typically from urinary tract infections with urease-producing bacteria, causes stone formation that causes painful urination, blood in urine, and straining while urinating. Common treatment types include invasive and noninvasive procedures to dissolve, flush out, or manually retrieve the struvite.
Therapeutic diets are one of the options to treat struvite. The process involves special diets coupled with medication. The diet, known as the cellulolytic diet, combines low magnesium, low protein, and low phosphorus with a diuretic and an acidifier. The diuretic promotes increased urine production and more urination frequency to help flush out struvite fragments.
The primary purpose of the diet is to restore and maintain regular urine pH levels, alongside regulating the levels of proteins and minerals the dog consumes. The therapeutic diet also stimulates the dog to drink water, aiding in the struvite dissolving process. Once the dog has passed the dissolved struvite, there is no longer a need to continue the formulation. Consulting a veterinarian is only necessary for recurring struvite and frequent bladder and urinary tract infections. On average, therapeutic diets take two to five months to dissolve the struvite. However, the results depend on the size of the struvite, with larger struvite taking longer to dissolve than the fragments.
Another treatment option is using antibiotics to treat bladder infections - the root cause of struvite. If the dog already has the struvite, treating the infection reduces the ammonium in the urine, thus reducing the formation of more struvite. Neglecting the root cause increases the chances of struvite recurrence. Combining antibiotic therapy and cellulolytic diets can optimize struvite elimination. It merges bacterial infection treatment and flushing out struvite fragments and sediments in the bladder. The dog requires a medical checkup every four weeks during antibiotic therapy for a urine test to monitor progress.
Ultrasonic dissolution is another option, though the procedure is available in select clinics. The veterinarian uses a high frequency of sound to break up the struvite into smaller sizes, followed by urohydropropulsion to evacuate the broken-up pieces or let them pass naturally.
Sometimes, the veterinarian may suggest mechanical retrieval procedures if antibiotics and therapy fail. One example is the voiding urohydropropulsion (UV) procedure. It involves inserting a catheter into the dog's urethra and flushing the bladder with a solution. Considering the flushed-out stones pass through the catheter tube, this procedure only works for small struvite. Due to the discomfort and the risk of injuring the urethra wall and bladder if the dog writhes, the method requires sedation.
Another minimally invasive technique, known as percutaneous cystolithotomy(PCCL), offers visualized access to the bladder and urinary tract and retrieves the stones alongside a sample of the mucosal lining for laboratory tests. A guided cystoscope, a thin tube with a light lens and a tiny video on one end to retrieve the struvite, is inserted into the bladder through an incision on the lower abdomen to retrieve the stones physically. The video visualization and magnification reduce the chances of leaving any stone fragments behind.
Lastly, surgical options are often for severe struvite cases, such as stones blocking the urethra, which often turns lethal. It is also recommended in case of failure of the dissolution procedure or severe cases of urolithiasis, a condition where kidney stones descend and accumulate in the bladder.
The surgical options offer the primary benefits of effective attendance to the struvite through qualitative and quantitative analysis, as the extracted stones can be physically analyzed. Surgery also effectively recovers renal function by manually removing stones blocking the urinary system, especially the bladder and urethra.
