Struvite problems

Urinary tract infections in dogs

Urinary tract infection (cystitis) is a relatively common disease in dogs. Owners typically have little difficulty recognizing urinary problems in their pets: dogs may have an increased need to urinate or exhibit urinary incontinence; they may drink more than usual or lick their genital area frequently; and urination is often painful. An untreated urinary tract infection can spread to the kidneys and cause pyelonephritis, a type of inflammation that requires urgent veterinary treatment. Occasional uncomplicated inflammation often heals quickly. Chronic inflammation, on the other hand, develops when a dog has primary diseases that predispose it to urinary tract infections, or when inflammation spreads to the kidneys. Cystitis is usually caused by bacteria. Normally, the dog’s immune system is able to prevent inflammation, and the urine flushes the bacteria in the bladder out of the body. Urinary acidity inhibits growth and replication of bacteria, as does the integrity of the bladder epithelium.

The most common cause of urinary tract infections are the faecal bacteria E. Coli, Klebsiella spp., Proteus spp., and Enterococcus spp., which move through the urine using their cilia. Inflammation develops when a bacterium attaches to the urinary epithelium and begins to multiply on the surface of an epithelial cell. Inflammation can also be caused by proteolytic, staphylococcal, and streptococcal bacteria. If the inflammation is allowed to spread to the renal pelvis and left untreated for an extended period of time, permanent kidney failure can occur.

A urinary tract infection can be most reliably confirmed with a urine sample taken by means of a bladder puncture. A puncture is especially necessary if the dog has recurrent urinary tract infections. Often, kidney values ​​are also checked through blood tests. The urine sample can also reveal the presence of urinary crystals and sediment, which may cause recurrent inflammations. In such cases, it is important to determine the number and location of the crystals using, for example, X-ray or ultrasound.

Urinary stones

Urinary stones are a familiar problem in dogs. In Finland, the most common minerals comprising canine urinary stones are struvite and calcium oxalate, though ammonium urate and cystine may also be present. The factors leading to the formation of urinary stones are complex and include infection, metabolic disorders, kidney absorption and reabsorption disorders, anatomical or functional defects of the lower urinary tract, genetic disorders, and improper nutrition promoting the formation of crystals. Dogs fed food containing large amounts of phosphorus and magnesium are particularly prone to the formation of struvite crystals. Grains, for example, are particularly high in magnesium. Sometimes crystals may also begin to precipitate around a foreign object in the urine. Urinary stones form when minerals in the urine begin to precipitate into crystals and then into urinary stones. The accumulation of minerals may be due to an increase in the excretion of minerals in the urine (e.g. calcium or cystine), or an increase in the amount of minerals in the urine due to bacterial inflammation (e.g. ammonium ions). The single biggest cause of calcium oxalate stones is considered to be an increase in the calcium level in urine, a condition known as hypercalciuria, which is more common in certain breeds of dog, such as the Miniature Schnauzer and Bichon Frise [1]. It has been found that struvite stones are more common in young dogs, while calcium oxalate stones are found in older dogs.

Urinary tract infection is the single greatest risk factor for the formation of struvite stones in dogs [1]. Struvite bladder stones usually arise as a complication of a bladder infection caused by bacteria producing an enzyme called urease, which breaks down the urea that is normally present in the urine. This leads to excess production of ammonia, which in turn causes the urine to become alkaline. Ammonia in the urine also causes bladder inflammation. Under such conditions, struvite crystals precipitate and collect around any cells or debris that may have accumulated in the bladder as a result of inflammation. In dogs, the most common bacteria isolated in struvite-related urinary tract infections are urease-positive Staphylococcus and Proteus [1].

Other risk factors for struvite stones include gender (females), breed (small breeds), sterilization in females, and certain findings in the urine (e.g. excess protein). Urinary stones damage the urinary tract epithelium and can even block the urethra. Other symptoms include difficulty urinating and blood in the urine. Urethral obstruction can cause toxic uraemia, a condition that requires immediate veterinary attention.

Calcium oxalate crystals are the second most common type of urinary stone to occur in dogs. The exact cause of calcium oxalate bladder stones is complex and not yet fully understood. Normal canine urine is slightly acidic and contains metabolic waste products, such as dissolved mineral salts and other compounds, which remain dissolved in the urine so long as pH levels stay within a narrow range and the urine does not become overly concentrated.

Current research indicates that acidic urine with high levels of calcium, citrates, or oxalates predisposes canines to the development of calcium oxalate urinary crystals and stones. Recent studies have shown that diets causing increased urine acidity (pH of less than 6.2) may make dogs prone to developing this type of bladder stone.

Urinary stones can occur anywhere in the urinary tract but are most commonly found in the bladder. The type and size of the urine crystals determine the appropriate treatment and diet. Stones can sometimes be flushed out of the urinary tract, and the proper diet may also help dissolve them; however, some types of stones can only be removed surgically. Regardless of the type of urinary stone, it is important to monitor the dog’s fluid intake, as good urine production can help flush crystals out of the bladder and prevent the formation of new stones.

Brit VD Struvite

Brit VD Struvite is a supportive diet for bacterial cystitis. It helps prevent crystalluria and dissolve struvite crystals and stones in the canine urinary tract. Brit VD Struvite is low in magnesium, calcium, and phosphorus to prevent urinary mineral over-saturation. Urine-acidifying agents added to Brit VD Struvite help keep urine pH balanced between 6.2 and 6.4. This promotes the dissolution of struvite crystals and prevents the formation of oxalate crystals. Added sodium improves fluid intake and promotes urinary excretion. Cranberries have also been added to Brit VD Struvite because they reduce the risk of urinary tract infection by acidifying urine and preventing E. coli from attaching to the urinary tract epithelium. The omega-3 fatty acids DHA and EPA can help prevent inflammation, while the live probiotic E. faecium stimulates the immune system. Brit VD Struvite is grain free and gluten free, and its main source of protein is egg, which is naturally low in phosphorus and protein. Brit VD Struvite should not be used with other urine-acidifying agents and is not suitable for dogs with chronic kidney or heart disease.

1) Suomen eläinlääkärilehti 5/18. Lahti S.et al. Mineral composition of uroliths in Finnish dogs from 1982 to 2012