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Lower urinary tract disease in cats (Proceedings)

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Aug 01, 2009

Lower urinary tract diseases of cats are a common, and sometimes frustrating, group of clinical problems that practitioners must deal with. Any disorder of the lower urinary tract may cause signs of lower urinary tract disease, the key is to understand the diseases that occur in cats and how they differ from the classic UTI/stone based diseases of dogs. In cats under 10 years of age, idiopathic cystitis (previously termed interstitial cystitis) is by far the most common cause of clinical disease, while in cats over 10 years of age, urinary tract infections are more common. The focus of this review is on the control, prevention and, where possible, treatment, of lower urinary tract disease in cats.

Feline interstitial cystitis

Feline lower urinary tract disease is condition characterized by painful, difficult or inappropriate urination (urinating outside the box), hematuria, and possibly the formation of stones in the urinary tract. The key is to recognize that there are many potential causes for the above symptoms: including crystalluria/urolithiasis, urinary tract infection or idiopathic. As many as 65% of cats under 10 years of age with lower urinary tract signs suffer from the idiopathic form of the disease – currently termed idiopathic cystitis – where there are no crystals, no UTI, no stones and no identifiable cause or if there are crystals or infection they are occurring secondary to interstitial cystitis as the primary cause. The classic progression of this disease is for the clinical signs to last 3-7 days with self resolution during that time (the reason why many have believed mistakenly that the signs resolved due to antibiotic or anti-inflammatory therapy). For these cats, no drug therapy to date has shown consistent benefit, and some drugs prescribed long term may have detrimental effects. However, in a controlled study, dietary therapy using a canned cat food diet designed to maintain a dilute urine and urine pH in the neutral range significantly reduced the rate of recurrence (90% did not recur over a 12 month trial period, compared to 60% of the control group). While there is still much to be learned about cats with idiopathic cystitis, increasing water intake and urine dilution appears to be very beneficial in the therapy of these cats.

Because the disease is associated with pain and mucosal hemorrhage due to defects in the bladder GAG layer – management is aimed at control of pain and prevention of complications of hemorrhage (blood clots forming concretions that cause an obstruction or nidus for crystal matrix formation). The inflammation associated with idiopathic cystitis in the bladder wall is not mediated by COX – mechanisms, thus, steroids or non-steroidal therapy will not result in significant control of discomfort. The most effective drug therapy for pain control in these cats appears to be opioids (buprenorphine or butorphanol). The best way to prevent clot formation or crystal nidus formation is to keep the urine as dilute as possible – thus, canned food, increasing water intake by other means, or giving SQ fluids are important aspects of therapy.

Finally cats with this disease, similar to humans with interstitial cystitis, appear to have co-morbid conditions as part of their disease: obesity, separation anxiety (and other stress responses) and hypertrophic cardiomyopathy. Research indicates that cats with idiopathic cystitis have an enhanced activation of the stress response system (sympathetic) from higher brain centers. Although more work is needed to fully understand this disease, therapy of idiopathic cystitis in cats should also be focused on methods of decreasing sympathetic responses. There is a website ( http://www.indoorcat.org/) that is dedicated to helping cat owners better understand this disease and indoor cat health.