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Cystitis in Cats

Otherwise known as Feline Lower Urinary Tract Disease or FLUTD

As many humans will know, cystitis is a very painful and distressing problem. In dogs and humans it is usually caused by infection in the bladder, but this is not the commonest form in cats. Except for older cats with kidney insufficiency (see kidney disease) it is unusual to see infection in cats' bladders. Their urine is a good disinfectant.

It has been known for a long time that cats fed on a dry diet are at some risk of developing crystals in their urine and that these can irritate the bladder or urethra and may lead to stones. Recent research has shown that almost all cats fed on dry cat food will have crystals in their urine, but not all of these have cystitis.

Microscopic view of a common type of urinary crystals (struvite) embedded in soft material forming a plug to obstruct a male cat

There is another factor (or factors) involved which are not yet fully understood. There is an increasing frequency of 'idiopathic cystitis' in cats. 'Idiopathic' means 'of unknown cause'. Research is being carried out to attempt to explain it and to find effective methods of treatment and prevention. For now it is a tricky problem.

What are the symptoms?

Most cats with cystitis will keep on passing urine in very small amounts and much more often than usual. They often pass blood as well and may tend not to use their litter tray. As long as they are managing to pass urine the problem is not dangerous, but is painful. Pain relief is a major part of treatment (do NOT use human pain-killers in cats!!!). The danger of cystitis in neutered male cats is that they may become obstructed with either blood clots or a plug made of crystals and mucus from the bladder lining. Obstruction means that they cannot pass urine and the pain increases dramatically. If the obstruction is not relieved within 24 hours there can be permanent damage to the bladder which can mean that the cat will have to be put down. The obstructed male cat often appears constipated. If in doubt get the cat checked as soon as possible.

X-ray of cat with positive(white) and negative (black) contrast in bladder. Plugs of material are visible as dark spots in the white region. These were removed surgically.


Generally pain relief is the first treatment as long as there is no obstruction. It is desirable to check a urine sample to ensure that there is no infection present and to assess the amount of crystalline material involved. Cats with idiopathic cystitis do not (according to experts) need antibiotics, though unless a urine sample can be checked it may be safer to give some. Otherwise feeding wet food with added water is often the most effective way to treat the problem.


If your cat has more than one bout of cystitis it is best to avoid feeding any dry foods at all. If your cat has not had cystitis then dry foods are probably perfectly OK. A few cats will keep on getting idiopathic cystitis and there are a number of treatments which can be tried, but none that is definitely going to work in all cats...yet. Otherwise there may be a stress factor (neighbouring cat attacking your cat when squatting in the garden, too many cats in the house, alterations in the house, new type of cat litter, etc) which to the cat is connected with urination and this may keep on triggering bouts. Removing the stress can solve the problem!

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