Feline Lower Urinary Tract Disorders'Cystitis' is a common veterinary term for an inflammatory process within the urinary bladder. In cats, cystitis occurs in both male and females and is usually referred to as Feline Lower Urinary Tract Disease (FLUTD), since the disease may affect the urinary bladder, urethra and genitals. It is usually a sterile (non-infectious) disease that involves inflammatory or mechanical (due to stones) irritation of the lower urinary tract. It is distinguished from feline upper urinary tract disease (FUUTD} which affects the kidneys and ureters of cats and is a much rarer syndrome in cats. Risk factors
The disorder may be caused by a combination of these factors. For example, a diet of dry food which is high in magnesium or other minerals and high in pH, combined with inadequate intake of water may lead to favorable conditions for precipitating buildup in the lower urinary tract. However, these factors affect individual cats differently. Most cats tolerate normal dry diets with no urinary problems. CausesThe exact cause of cystitis is unknown, but certainly many of the usual suspects are incriminated, in order of importance;
The average age of a cat with FLUTD is 4 years. Of all cats with FLUTD:50% will not have a cause which can be determined despite extensive testing
Until recently, it was thought that most uroliths in cats were small and resembled sand or were gelatinous plugs that differed from typical uroliths in that they contained a greater amount of organic matrix, giving them a toothpaste-like consistency. Matrix-crystalline plugs are most commonly found within the urethra near the urethral orifice and are primarily responsible for urethral obstruction. Recently, prevalence of urolithiasis with grossly observable stones composed primarily of calcium oxalate has increased in cats. The most common feline uroliths are calcium oxalate, magnesium ammonium phosphate (struvite), and urate. Diagnosis
TreatmentIn acute medical cases of urethral blockage and bladder overfilling, feline patients should have ECG monitoring before and during anaesthesia for catheterisation. Cardiac disturbances can be seen with K+ above 6.5-7.0 mmol/L; and these may include bradycardia, atrial standstill, spiked T-waves, accelerated idioventricular rhythm, ventricular tachycardia, or fibrillation. Therapy for hyperkalaemia should be instigated.Relief of obstruction should be attempted without GA in extremely depressed cats. If restraint is required, use low dose diazepam/ketamine (1-2 mg/kg IV) or propofol IV. Otherwise, general anaesthesia is induced (with either propofol, diazepam/ketamine, or alfaxolone) and maintained with isoflurane and oxygen. Male cats who frequently suffer from cystitis and blockage of the urethra have a high risk of kidney damage and sudden death due to bladder rupture. In these cases, the cause is usually the presence of large quantities of urinary crystals in the bladder. Surgical intervention usually involves either a cystotomy or perineal urethrostomy. With a perineal urethrostomy, (often called a 'sex change operation'), the penis is amputated and the urethra exteriorised as a makeshift vagina-like opening, thus preventing any further blockage of urine. Although considered a drastic step, this operation is usually successful and stops further pain and disease in the cat and is recommended in male cats that have had a urethral obstructions three times or more. A cystotomy is much less surgically demanding and has a higher success rate if the cat is prevented form eating dry food in the future. It also has the advantage of being more cost effective in the long term as complications are minimal. MedicationMonitor for post-renal azotaemia due to tubular back-pressure causing a reduction in the GFR. Monitor also for post-obstructive diuresis then maintain fluid balance in light of post-obstructive diuresis (normal urine output is 1-2ml/kg/hr). Consider using phenoxybenzamine or prazosin as an alpha-1 antagonist to relax the internal urethral sphincter. Consider starting as soon as the urinary catheter is in place. Acetylpromazine also has alpha-1 antagonist activity, so can be used to sedate and help express bladders if there is some functional obstruction post-catheter removal. The use of pentosan polysulphate to minimise clinical signs is at present debatable.Routine analgesia is preferred, using NSAIDs (e.g. meloxicam) as a primary choice of drug. Dietary changeThe presence of crystals suggests that a diet change is in order, including adding urinary acidifiers such as Acidurin® to help keep the urine acidic and prevent further crystals from forming. It is also important to feed the cat dry food that is low in minerals and which produces and acidic urine (such as Hills C/D diet®) or else avoid dry foods altogether and feed only fresh food or tinned food, which have a higher moisture content. Because cats that get cystitis normally have recurring problems, it is important to keep them on a modified diet, urinary acidifying tablets and reduced stress.One aspect of long-term management of FLUTD is to promote increased water consumption by the cat. This can be problematic as cats are reluctant drinkers. Increased drinking has been thought to increase the mechanical flushing of the urinary bladder and thus reduce the formation of crystals. One method of stimulating water intake in cats is by increasing the salt content of the food. Canned food are a frequent recommendation as they contain 70-80% water. Several studies have shown that increasing dietary salt (NaCl) can increase water intake and urine volume, and decrease urine specific gravity2. It has been suggested that increased salt intake in cats with existing FLUTD may aggravate underlying kidney disease and elevate blood pressure, but a comprehensive study by Xu et al showed that changes in dietary salt intake had minimal effects on total body hydration status, blood pressure and markers of renal function3. Rather than a risk factor, they also noted that increasing salt in diet had a protective influence against the development of chronic renal disease in cats. References:Wikipedia, FLUTDCornell University Felipedia Fabcats Related Pages:Recognizing Illness in CatsCat First Aid Food for Cats Guest Article by Laura Ramirez, UTI and Cat Foods Guest Article by Kate Reiger, UTI and Commercial Cat Foods Holistic FLUTD Care
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