Approaches to dealing with FLUTD

Vet Times The website for the veterinary profession https://www.vettimes.co.uk Approaches to dealing with FLUTD Author : Rachel Sant Categories : Vets Date : May 14, 2012 Rachel Sant discusses causes of feline lower urinary tract disease, diagnostic techniques, treatment and management of the condition Summary Feline lower urinary tract disease is a common condition. Cats may present as an emergency if there is urethral obstruction. Feline idiopathic cystitis is the most common diagnosis made in the UK and is a diagnosis of exclusion. Urinary tract infections are rare in healthy young cats and are generally only seen in those with underlying diseases, such as renal failure or diabetes mellitus. Urinalysis and imaging are important diagnostic tests. Recurrent disease is common so owner communication and co-operation are vitally important. Environmental changes are helpful in reducing the frequency and severity of idiopathic cystitis episodes, as is production of dilute urine. Key words urethral obstruction, idiopathic cystitis, urine specific gravity FELINE lower urinary tract disease (FLUTD) was previously known as feline urological syndrome, when it was thought to be related to crystal and stone formation (urolithiasis) within the urinary tract. Now crystals are understood to be formed in most, if not all, cats that eat dry food, we know uroliths are not the most common cause of FLUTD. 1 / 8

The lower urinary tract consists of the bladder and urethra. Cystitis (inflammation of the bladder) and/or urethritis (urethral inflammation) are commonly seen in cats and may be due to many different causes. Cystitis can be caused by bacterial infections, urolithiasis, neoplasia, anatomical abnormalities, or may be idiopathic. Presenting signs include dysuria, pollakiuria (increased frequency of urination), haematuria, urethral obstruction, periuria and vocalisation. Inflammation within the urinary tract, whatever the cause, tends to produce the same range of symptoms. Feline idiopathic cystitis (FIC) is the most common disease causing FLUTD and is diagnosed by the exclusion of all other causes. It is more common in cats that are young to middle aged, overweight and that live in a multi-cat house-hold. The cause is unknown, but the current hypothesis is that there is an alteration in interactions between the bladder nerve supply, the glycosaminoglycan (GAG) layer lining the bladder and compounds within the urine, causing inflammation of the bladder wall. Biopsies of bladders from affected cats show submucosal oedema, vasodilation and increased numbers of pain fibres and pain receptors. Susceptible cats appear sensitive to environmental stress, which can manifest in this way in the urinary tract via the nervous system. There are many similarities to interstitial cystitis in humans and recurrent disease is common (in one study 65 per cent of cases had more than one episode). Episodes of FIC are generally self-limiting, which means that treatment appears to be effective when it may not actually be having any effect. A full history should be taken including whether there have been any previous episodes, signs of obstruction and the environmental history. Male cats are more likely to obstruct than female cats. Older animals may have concurrent disease and be more likely to have urinary tract infections (UTIs), so owners should be questioned about signs of systemic disease. It may be difficult to distinguish true behavioural problems from physical disease in some cases and a behaviourist may need to be involved, although ruling out physical disease should be performed first. Clinical examination is important, particularly in ascertaining whether the cat is blocked or not. Cats with urethral obstruction usually have non-productive straining (owners may interpret this as constipation), discomfort and may vocalise. Palpation of the abdomen generally reveals a full, hardfeeling bladder and is associated with pain. General clinical examination is important to look for other diseases including metabolic diseases, which may be secondary to urethral obstruction for example, bradycardia associated with hyperkalaemia. Differential diagnosis of FLUTD Urinary tract infections Normal host defences mean UTIs are uncommon. Normal bladder anatomy and full bladder emptying, plus the inhibitory effect on bacterial growth by normal concentrated cat urine, mean bacteria do not get much chance to reproduce in a normal cat s bladder. 2 / 8

Infection is more of a problem if there is damage to the mucosa (for example, due to uroliths, neoplasia or iatrogenic damage during catheterisation), systemic disease causing dilute urine, or if there are any anatomical defects for example, urachal remnant, which can allow residual urine to remain in the bladder after voiding. Infection can also persist in a thickened bladder wall (for example, secondary to previous infection or neoplasia). If you are presented with a young, healthy cat you should not be overly suspicious of infection, but if there are signs of concurrent disease, or if the urine is dilute, you should always perform a bacterial culture. Examining urine sediment first is also helpful, as if you see neutrophils and bacteria then culture should be performed. In dilute urine, or urine from cats with diseases where the immune system is not working well, it is common to have infection without active sediment. Thus, in these cases, culture is ideally performed in all patients. Urolithiasis Urolithiasis is the formation of uroliths anywhere within the urinary tract, that is, kidney, ureters, bladder and urethra. Urinary crystals do not always form into uroliths and, in fact, crystals are commonly found in urine of any cat fed any amount of dry food. Struvite (magnesium ammonium phosphate) and oxalate uroliths are the most common. Diets designed to reduce the formation of struvite (generally acidifying diets) have led to an increase in the incidence of oxalate stones over the past few decades. Oxalate occurs more commonly in certain breeds (such as Persians) and in animals with hypercalcaemia. Not all cats with obstruction have uroliths since their obstruction can occur due to a proteinaceous matrix, which leaks from the urinary tract as a result of inflammation, although struvite crystals are often found in association with proteinaceous urethral plugs causing obstruction. For this reason, if you find crystals in an obstructed cat you should not assume that urolithiasis is the primary cause. Neoplasia The most common bladder tumour in cats is transitional cell carcinoma. Cytology of urine may show large epithelial cells, which exhibit anisocytosis and anisokaryosis. Other bladder tumours include urothelial carcinoma, squamous cell carcinoma and lymphoma. Cytology can be helpful, but in the face of infection, nonneoplastic cells can become dysplastic and difficult to differentiate from neoplastic cells. Histopathological samples are more reliable and samples can be taken by suction via a urinary catheter positioned at the level of the abnormality. Polyps and polypoid cystitis can sometimes be hard to differentiate from neoplasia on imaging studies and epithelial cells may be shed into urine, so can also be difficult to distinguish 3 / 8

cytologically in which case, histological examination is also required. Diagnostic tests The choice of diagnostic tests may depend on the individual case. For example, it may be perfectly acceptable to do just urinalysis (with or without bacterial culture) on a healthy cat at first presentation. If the cat presents again, imaging is sensible to rule out neoplasia or anatomical abnormalities. If the patient presents with urethral obstruction then proceed to further tests more urgently. Blood sampling, urine sampling (dipstick, sediment examination, bacterial culture), radiography (plain and contrast), abdominal ultrasound or cystoscopy may all be considered. Blocked cats Cats with urethral obstruction are diagnosed on history and clinical signs, including careful palpation of the abdomen. Blocked cats are often azotaemic, hyperkalaemic and acidotic, so blood sampling is useful prior to sedation, especially urea, creatinine, potassium, and blood gases if available. Fluid therapy should be started. Ideally, a potassium-free fluid should be used, such as saline, but Hartmann s solution is also okay as the main aim is to unblock the bladder, which will reduce the potassium level whatever fluid is used. In cases where the potassium is extremely high, specific treatment should be given (calcium gluconate can stabilise the heart prior to potassium level reduction; bicarbonate can be given if acidotic and if you can measure blood gases, but is best avoided otherwise). Relief of obstruction is the main aim. You should catheterise and then remove the urinary catheter if possible (in cases where this is the first episode and catheterisation was easy). If it is not possible to catheterise the urethra then you can perform a cystocentesis using a small gauge needle (25g needle or butterfly). It is important to fully empty the bladder when performing a cystocentesis as there is a risk of leakage if you make a hole and leave the bladder full. Larger gauge needles may also be associated with urine leakage. In cats where catheterisation is impossible you could, as an alternative to cystocentesis (or if multiple centeses are expected), insert a pre-pubic cystostomy tube. Whatever method is used, you should flush the bladder with saline after emptying to remove inflammatory mediators. Rectal exam at the time of catheterising is also useful to feel for urethral stones. If stones are palpated then retrograde hydropulsion can be used to push the obstructing stones back into the bladder where they can be surgically removed (preferable, for analysis) or dissolved by diet. If the cat is stable, radiography could be a consideration at this stage. 4 / 8

Try not to leave catheters in if possible as they traumatise the urethra (or bladder if the catheter is longer than the bladder neck). You may need to leave them for two to three days if there is urethral trauma, if the cat has had multiple episodes of urethral obstruction and/or if there is urethral spasm. If a catheter is left in, always use a closed collection system to reduce the risk of infection. Monitor urine in and out if catheterised as postobstructive diuresis is common and you need to make sure enough fluid is going in. Urine sediment and culture UTIs are uncommon except in specific cases, as discussed previously. Urine can be collected in a variety of ways. Collection from non-absorbent litter is easy and suitable for dipstick examination, but not suitable for sediment or culture. In cats you are catheterising to unblock, and urine obtained in this way can be analysed. There will always be some contamination, so bacterial counts can be higher in urine obtained by this method than in cystocentesis samples. Cystocentesis is probably the most useful sampling method, although a small amount of blood will be present in the sample. Dipstick and sediment analysis should be done in-house immediately, or as soon as is practically possible. Culture and sensitivity should be performed if bacteria are seen (especially if seen in association with neutrophils, suggesting infection rather than contamination) or if you are suspicious of the possibility of a UTI without seeing bacteria for example, in cats with renal failure or low urine specific gravity. Dysplastic or neoplastic cells may be seen in urine although they can be difficult to differentiate. Crystals will precipitate out as the urine cools, but small numbers of crystals are seen often, even in warm urine. Urine culture may be negative in some cases, even where infection is present, and you may need culture of the bladder wall in chronic cases where bacteria can be protected within the thickened bladder wall, or in cases of urolithiasis, where bacteria can be held within the layers of the stones. Imaging Imaging of the urinary tract can be done with radiography or ultrasound or both. Each has its good and bad points. Plain radiographs can be used to visualise radio-opaque uroliths, kidney and bladder size, emphysematous cystitis or some abdominal masses. Contrast (using positive or negative contrast) radiographs will also pick up radiolucent uroliths, intraluminal masses (such as clots, neoplasia and polyps), bladder wall thickening, a urachal remnant, extravasation of contrast and can also be used to assess the urethra. Figures 1 and 2 show negative contrast radiographs (pneumo-cystogram of a normal bladder and one containing uroliths) and Figure 3 shows a normal bladder after double contrast (positive contrast and air). 5 / 8

Ultrasound will also pick up intraluminal masses, bladder wall thickening and can assess changes within the parenchyma of the kidneys. The urethra cannot be visualised via ultrasound, but the ureters can be seen in some cases (especially if they are enlarged). Cystoscopy and biopsy Cystoscopy can be used to take bladder wall biopsies and typical lesions of FIC can be visualised cystoscopically, as can uroliths, but this modality is not available in many centres. Treatment Treatment will depend on the diagnosis. If there is an underlying disease then this must be treated. However, idiopathic cystitis is the most likely diagnosis and can only be managed. Treatment options may also vary depending on whether the cat is blocked on presentation or not, that is, you may have to be more aggressive with, for example, antispasmodics in a blocked male cat compared to a female cat with intermittent cystitis. Diet A specific diet may need to be used if there were stones present that you have removed and had analysed. The type of stone should never be guessed and it is not always safe to assume that bladder stones will have the same constituents as crystals present in the urine. Surgical removal of uroliths and full analysis is the best approach to the first presentation of urolithiasis. Female cats may be able to have stones voided using the technique of hydropulsion (filling the bladder and then holding the cat vertically to collect the stones in the bladder neck and firmly pressing the bladder to fully empty it, but this is only possible with very small stones, which can exit through the urethra). Generally, surgically remove all the stones on the first presentation to be sure you have full stone analysis and are treating the correct condition. Acidifying diets should not be used in cats that have asymptomatic crystalluria, and increasing water intake (which reduces the saturation of chemical constituents of uroliths) is the best option. FIC management Increased water turnover to produce urine with a low specific gravity is important as it will help to manage both urolithiasis and FIC. Aim for a urine specific gravity of below 1.035. Other tips to reduce the incidence of FIC include increasing the availability of resources within the household (water bowls, food stations, litter trays, resting and hiding places). Some cats will drink more if water fountains or other places are available from where they can obtain running water. Water can also be added to the cat s diet or owners can provide broths made with, for example, 6 / 8

chicken gravy, to encourage increased water intake. Feline facial pheremones may help reduce stress within a household and reduce the frequency or severity of cystitis episodes. Supplementation of GAG, to theoretically alter the bladder lining, has been used. There is no strong evidence for its use although some cats appear to respond more favourably than others. References and further reading Villiers E and Blackwood L (eds) (2005). BSAVA Manual of Canine and Feline Clinical Pathology (2nd edn), BSAVA, Gloucester. Nelson R W and Couto C G (1998). Small Animal Internal Medicine (2nd edn), Mosby, St Louis. Bexfield N and Lee K (eds) (2010). BSAVA Guide to Procedures in Small Animal Practice, BSAVA, Gloucester. Gunn-Moore D A (2003). Feline lower urinary tract disease, Journal of Feline Medicine and Surgery 5:133-138. Gunn-Moore D A and Cameron M E (2004). A pilot study using synthetic feline facial pheromone for the management of feline idiopathic cystitis, Journal of Feline Medicine and Surgery 6: 133-138. Gunn-Moore D A and Shenoy C M (2004). Oral glucosamine and the management of feline idiopathic cystitis, Journal of Feline Medicine and Surgery 6: 219-225. TIPS FOR UNBLOCKING URETHRAL OBSTRUCTION Shave the cat locally to reduce the risk of introducing infec-tion from the environment (fur, skin and your hands are the main sources of infection), use lubrication, extrude its penis and insert catheter into the end and flush with saline while trying to advance the catheter. It sometimes helps to release the penis and to allow it to retract back into the prepuce once the catheter is part way in and/or to pull the prepuce caudally at this stage, while still flushing. Lachrymal cannulas can be useful in difficult cases to unblock the first few centimetres of urethra. Flush with saline until clear after unblocking. Always use analgesia and consider drugs that reduce urethral spasm. DRUGS USEFUL IN THE MANAGEMENT OF FLUTD Buprenorphine 0.01mg/kg to 0.03mg/kg every four to 12 hours. 7 / 8

Powered by TCPDF (www.tcpdf.org) NSAIDs for pain relief. Meloxicam has also been used for palliative treatment of transitional cell carcinoma. Antibiotics are not helpful in feline idiopathic cystitis only for infection and on the basis of culture and sensitivity. Long courses may be required if there are uroliths or chronic bladder wall thickening (four to six weeks) and repeat culture during course and after finishing course is recommended. Antispasmodics, for example prazosin or phenoxybenzamine. Neither are licensed in the UK for use in cats. Prazosin is the most useful as phenoxybenzamine usually takes a few days to reach full effect. 8 / 8