What is it?Cystitis just means "inflammation of the bladder". In dogs, we usually mean a urinary tract infection (bacteria growing in the bladder), but cystitis can also be caused by bladder stones (urolithiasis) or, rarely, a bladder tumour.
What causes it?
By far the most common cause of cystitis in dogs is an ascending infection - bacteria that crawl their way up the urethra (the "urine tube") from the outside world. This is much more likely in dogs where the bladder is a less hostile place - for example, diabetic dogs (where the urine contains lots of sugar for the bugs to feed on), those with Cushing's disease (where the immune system is impaired), and those with unusually dilute urine (e.g. Cushing's, Psychogenic Polydipsia, or Diabetes Insipidus).
The bacterial infection damages the bladder wall, resulting in symptoms. It is now thought that in some cases, the bacteria may in fact penetrate further, causing a kidney infection. If bladder stones form, there are a number of different types; the most common, struvite, forms because of an infection, whereas other types may reflect an imbalanced diet, or a metabolic defect (e.g. liver disorders leading to urate stones).
These stones then rub against the wall of the bladder, causing irritation (just like an infection would). Occasionally, in older dogs, a tumour (or cancer) of the bladder wall may form, also causing the clinical signs.
What dogs are at risk?Female dogs are at a much higher risk of infection, because their urethra is shorter and wider, so bacteria can more easily enter along it. Bladder stones are most often secondary to an infection, but some dogs (such as Dalmatians) are at an increased risk due to certain metabolic differences, and any dog with liver disease is also at increased risk. Bladder tumours, meanwhile, are most common in older dogs.
What are the symptoms?
The symptoms may be subtle or very obvious, depending on the severity and the specific dog! However, they most commonly include:
- Blood in the urine.
- Urinating often, but only producing a small amount each time.
- Pain on urination.
- Sometimes, incontinence may seem to occur.
It is unusual for cystitis to cause a fever or other signs of systemic infection (such as lethargy or loss of appetite); if this occurs, it suggests a more serious condition such as a kidney infection. If your dog is trying to pass urine and isn't able to, they may have a stone blocking their bladder - this is an emergency and needs IMMEDIATE veterinary attention.
How is it diagnosed?
Most commonly, cystitis will be diagnosed with a urine sample. The presence of blood suggests significant irritation to the bladder wall, and often we can see (or grow) bacteria in the urine. A urine sample mustn't be collected from the floor or ground, because we won't be able to check for infection - instead, it should be collected in mid flow (the use of a shallow dish or saucepan may help!).
Other tests on the urine may demonstrate crystals (suggestive of stones forming) or abnormal cells (suggestive of a bladder tumour). If stones or a tumour are suspected, X-rays or ultrasound scans may be required to find and localise them.
How can it be treated or managed?
The vast majority of dogs with cystitis will respond really well to simple treatment with a course of antibiotics. The use of a urine sample to grow the specific bacteria (culture and sensitivity testing) will allow us to choose the most appropriate and effective antibiotic.
If there are bladder stones, it may be possible to dissolve them with a special diet; however, some stones are too large, the wrong type, or in the wrong place (for example, blocking the bladder) for this to work, and in these cases they must be surgically removed. Bladder tumours are, sadly, usually inoperable, but there are some medical treatments that can reduce the severity of the symptoms, making the dog more comfortable.