Bladder problems are relatively common in dogs, and despite varying causes, have very similar presenting signs of blood in the urine (haematuria), difficulty or pain when urinating (dysuria), increased frequency of urination (pollakiuria) and leaking urine.
Urinary tract infections (cystitis) typically occur more frequently in females due to anatomical differences. Most infections are ascending up the urethra from outside into the bladder. Females have a short, wide tube but males have a narrow, long tube which makes it more difficult for bacteria to enter the bladder. The most common symptom is the need to pass urine more often than usual, but this is often accompanied by haematuria and dysuria. Dogs will repeatedly squat to urinate but pass small spots of urine only.
If a dog presents with haematuria, dysuria and pollakiuria with acute onset, then it is usually assumed the dog has cystitis and will be prescribed a course of antibiotics. If possible, a urine sample will be obtained- this can be checked for the presence of blood, protein and inflammatory cells. All of which indicate cystitis. In the majority of cases a course of antibiotics will treat the condition, but if the symptoms recur or don’t resolve further investigation is necessary.
Recurrent cystitis would indicate that urine culture and sensitivity is necessary. This determines the exact bacteria present and what antibiotic is best used to resolve the infection. Sometimes a long course of 4-6 weeks is needed and a repeat culture to ensure the infection is clear. If the culture is negative and symptoms persist then further investigation is required. If glucose is present in the urine, then the patient could be diabetic- they are more prone to recurrent infections because the bacteria feed off glucose in the urine.
The ph. of the urine is normally neutral to slightly acidic. If the ph. is alkaline this can predispose your pet developing bladder stones (uroliths) from crystals that form from minerals that are normally dissolved in the urine. These are relatively common and are seen in both males and females. The most common type of urolith is called struvite. The stones irritate the bladder lining and cause pain and bleeding. In rare cases the stones can leave the bladder and block the urethra (the tube leaving the bladder). This is much more likely to happen in males due to the long, narrow urethra. This is an emergency as kidney failure can develop if urine is not able to be voided.
Urinalysis can confirm the presence of a high number of crystals- this alone can cause symptoms due to irritation of the bladder lining. Bladder stones are most easily diagnosed with an X-ray or ultrasound. Most cases diagnosed with a urolith will require a surgical procedure called a cystotomy to remove the stone, but some types of small stones can be dissolved with special diets. Once removed the stone will be sent to a lab for analysis and depending on the type of urolith diagnosed a therapeutic diet may be prescribed to dissolve any remaining crystals and prevent re-saturation of the urine with minerals which leads to stone formation.
Sterile or inflammatory cystitis causes all the same symptoms as a bacterial cystitis, but the urine culture is negative. In these cases, a bladder X-ray will be clear of stones, so an ultrasound is used to look for changes within the bladder walls. With inflammatory cystitis the bladder wall is thickened. This condition can be recurrent and often tricky to manage. Some cases respond well to anti-inflammatory drugs and stress management.