Of all the cases of cystitis we see in cats, around 65% of them are classified as being idiopathic, with no obvious underlying cause. As a feline clinician, you’ll understand how frustrating they can be to manage, and many are likely to get recurrent bouts which can take days or weeks to settle.
Why do cats get Idiopathic Cystitis?
The clue is in the name, and by definition we often fail to find a cause. There are however a number of triggers that lead to the problem. Three of these include;
- Stress – there is no doubt that the multifactorial role of stress is critical in initiating and prolonging the signs of FIC. For many cats, recurring episodes of cystitis can be triggered by stress events of all forms. Stress results in the release of adrenaline, noradrenaline and cortisol. Cats with FIC usually have raised catecholamine levels typical of a stress response, whilst frequently have atypically low cortisol levels, illustrating that they are not responding to stress in a normal way.
- Defective bladder protection - a key finding in cases of FIC is that the normal mucous layer lining the inner wall of the bladder becomes ineffective and deficient. This mucus, formed from glycosaminoglycans (GAG), and which lines the bladder wall, would normally prevent the irritating properties of feline urine from affecting the transitional epithelial cells of the bladder wall. The consequences of this are that these cells can become damaged, ulcerated and inflamed.
- Neurogenic stimulation – local irritation can result in the release of neurotransmitters which lead to overstimulation, inflammation and pain associated with the bladder wall.
What are the signs of FIC?
Many of the signs are similar to those shown in other forms of lower urinary tract disease. Look for;
- Dysuria – cats with FIC have difficulty urinating. Owners will notice their pet straining to urinate without producing any urine.
- Haematuria – this is often a big worry for owners as they will see bloody urine, with urethral plugs that resemble clots. The cat litter will often become discoloured.
- Periuria – cats urinate outside the litter tray, sometimes just around the edge of the tray or perhaps in corners and on carpets around the home.
- Pollakiuria – the patient will make multiple attempts to urinate, producing very little or no urine.
- Blocked urethra – this is primarily seen in male cats and needs to be treated as an emergency. It results from urethral inflammation, plugs and smooth muscle spasm.
- Thickened bladder wall – this can be identified by radiography and ultrasound.
Many of these signs appear suddenly and then slowly improve over a week or two. Some unlucky animals will have the signs persisting for weeks. In most cases of FIC, the troubles recur despite the best efforts to help, but you can reassure the owner that most cats will improve, and some may spontaneously recover as they get older.
Making a diagnosis
With FIC there is no specific test you can use to confirm your suspicions, so you need to eliminate all other possible causes of cystitis first. Use your full armoury of tests, such as;
- Urinalysis – use a fresh urine sample, and if you don’t have time to examine it straight away, then store it in the fridge. Use dip sticks to look for protein and blood, measure SG with a refractometer, and look at the sediment for crystals and cells. Simple Diff Quick tests can be used to identify individual cell populations.
- Identify pathogens – whilst bacterial infections are uncommon, always check by sending a fresh sterile sample away to your preferred laboratory for culture and sensitivity tests.
- Radiology – x-rays are used to check for uroliths, bladder wall integrity and pathology. Positive and negative contrast imaging can be used to highlight radiolucent structures.
- Ultrasound – this is non-invasive and generally available in many practices. It’ll offer detailed information on the bladder wall and urethra, as well as help identify crystals, neoplasia and inflammation.
Helping a cat with FIC
Once you’ve made a diagnosis of FIC, you’ll need to find ways to help. Owners will be desperate to alleviate the discomfort and stress. A multimodal approach can be used with attention to diet and the environmental, together with some drug assistance as required.
A. Dietary management of FIC
Diet does seem to have an influence on the development and recurrence of FIC. Compared with wet food, dry food tends to lower urinary volume, which also produces concentrated urine which can potentially irritate the bladder wall. It therefore helps to offer wet food, whilst at the same time supporting and stimulating drinking. This can be achieved in a variety of ways, such as;
- Multiple shallow bowls – place water in various places about the home, and feed from at least as many bowls as there are cats.
- Flavoured water – add tuna water drained out of a tin of tuna, or perhaps a few mls of chicken broth in the water bowl, and you’ll encourage may cats to drink more water.
- Running water – water fountains have been used with success to encourage cats to drink more.
- Soften dry food – some cats will become accustomed to and prefer dry food that has been soaked, thereby consuming more water.
- Wet food – cats with recurring FIC tend to do better when fed wet food. The additional fluid helps produce more dilute, and therefore less irritant urine.
- Polyunsaturated fatty acids – many commercial feline diets are supplemented with these fatty acids, which may help reduce inflammation.
- Avoid excessive minerals – thereby reducing the potential to produce irritant urinary crystals.
B. Alleviate stress
This is certainly one of the most important things you need to do to help a cat with idiopathic cystitis. Cats are such sensitive animals, becoming stressed by a myriad of seemingly inconsequential triggers. Your skills can be used to find them and make suggestions on how the owner can alter the home environment to help.
C. Drugs used in FIC?
Most cases of FIC don’t respond well to drugs. The aim should therefore be to identify what are the most likely triggers (i.e. stress) and find ways to minimise or remove them. However, if all attempts to do this have failed, then drugs may be considered. The three therapeutic approaches include the use of;
- Glycosaminoglycans replacers – examples include pentosan polysulphate and glucosamine. Whilst there is no absolute evidence that they work, trial therapy is certainly warranted in refractory cases as it seems that some cats may genuinely benefit from their use.
- Tricyclic antidepressants – amitryptiline has been used as it has a number of potential beneficial effects of reducing neurogenic inflammation in the bladder and controlling the discomfort associated with the disease.
- Analgesics - FIC is certainly a painful condition, so always consider using NSAID’s, butorphanol and buprenorphine.