by Barry B. Burtis D.V.M.
Feline Idiopathic Cystitis
In a recent column I wrote about feline house soiling, sometimes caused by behaviour problems, and some of the things cat owners and veterinarians do to try and resolve the disorder. This time I want to discuss a disease that, also, may cause cats to urinate, inappropriately, outside their litter boxes. In fact, some feline medicine researchers suggest this condition may be responsible for nearly 50% of the cases that until recently were diagnosed as behaviour problems.
The disease is most commonly called feline idiopathic cystitis (FIC). This disorder is thought to very closely resemble a chronic inflammatory condition that affects the urinary bladder of humans known as interstitial cystitis. According to the United States National Institutes of Health, 700,000 people in that country are affected by that disease. Of those persons afflicted, 90% are women. Some health authorities suspect the number of sufferers may even be higher than those reported because the disease is quite difficult to diagnose. It must be stressed there is no suggestion this disease spreads from cats to people or from people to cats.
One of the symptoms often shown by a cat that has FIC is urination in inappropriate locations. They may also exhibit painful or difficult urination, they may try to pass urine more frequently than usual and often the urine voided is blood coloured. Informed cat owners need to remember that these signs can also be caused by other health problems that may affect their pet. Bacterial infections in the urinary bladder are a common cause for these clinical signs in a cat. Also, cats quite frequently can experience difficulties with urination when they have formed mineralized or other precipitates in the urine. Trauma, anatomic abnormalities or cancers may also lead to the symptoms described. Also, even an experienced cat owner, may sometimes confuse the signs caused by constipation with problems involving the urinary tract.
Researchers studying urinary system disease in cats believe this is how the problem develops. The lining tissue of the urinary bladder is protected from toxins or poisonous ingredients in the urine by a layer of protein called glycoaminoglycan (GAG). In cats who suffer from FIC this protective layer has broken down allowing the urine to irritate the bladder wall. The bladder becomes inflamed, does not store urine well and pain mechanisms are triggered. Hence, all the signs we see in an affected cat. There are still many questions as to what may cause the breakdown in the GAG layer in the first place. Although none have yet been found, it is still possible that viruses or other infectious agents may play a part in the disease process. It is also possible that it is just a result of a deficiency, for some reason, of GAG.
It can be very difficult to confirm a diagnosis of FIC in a cat. As mentioned earlier the same is true in the diagnosis of interstitial cystitis in humans. There is no simple urine or blood test able to prove the disease is present. Rather, it becomes more a diagnosis by exclusion of other possible causes for the trouble. Laboratory tests done on urine samples will make sure that infections or mineralized precipitates in the urine are the not cause of the problem. X-rays and ultrasound imaging can be done to investigate for other diseases. Behaviour therapies will need to be considered to rule out problem behaviour as the reason for the trouble. Once these other causes have been eliminated as possibilities it may be more appropriate to begin some treatments for FIC rather than continue with further diagnostics. Further testing would probably require direct examination of the internal bladder wall with the help of an endoscope and the collection of biopsies if affected areas can be seen. Such testing, although occasionally done, is not simple and is not inexpensive.
Because the underlying causes of FIC are still incompletely understood, treatment recommendations cannot be specific. The symptoms described above that are shown by cats with FIC often spontaneously resolve within a couple of weeks regardless of treatment. Therefore most efforts are directed at trying to prevent recurrences of the problem. Stress seems to be very important as a cause of flare-ups of FIC. Many things may cause stress in a cat's life - changes in environment, weather, activity, use of the litter pan, food intake, owner work schedules, additions or subtractions from the household population of humans or animals and other factors. It may be difficult to identify and eliminate stress for an affected cat but some efforts in this area will need to be made. A feline pheromone that exerts a calming effect on cats may be helpful in reducing anxiety for some. Studies have been done that suggest recurrence rates can be reduced if an affected cat's diet is changed to a canned food diet only. Veterinarians also may recommend the use of analgesics or drugs that reduce the activity of bladder wall muscles. Results of clinical trials to determine if other medications may be helpful in the treatment of this disorder are still not available.