Feline lower urinary tract disease (FLUTD) is a set of diseases that afflict a small percentage of the cat population. The reported rate of new cases each year is less than one percent of the cat population. Approximately ten percent of the cats who come to veterinary clinics have some type of lower urinary tract disease. For many years, this set of diseases was lumped together under the name Feline Urologic Syndrome (FUS). Too often this term became associated with a specific disease. However, the affected cat could be suffering from one of a collection of urinary tract diseases that have common symptoms, but unfortunately a diagnosis with an etiology (or specific cause) is not often made. In other words, lower urinary tract disease is not a "what is" but a "what are." It is a group of diseases and because it is more than one disease, there is more than one cause. The complex nature of urinary tract diseases requires veterinary diagnosis and treatment.
FLUTD can happen in both male and female cats, and it usually occurs in cats between 2 and 6 years of age. However, cats of any age may be affected. FLUTD tends to be associated with a number of factors, including urolithiasis (or stone formation), stress of any kind, obesity, cats housed indoors, viral infections, seasonal weather, anatomical abnormalities, bacterial infections, and breed differences. Because male cats have a narrow urethra, they tend to be more prone to complete obstruction than females, and without prompt veterinary treatment these obstructions can be serious, even fatal.
The symptoms of FLUTD are well known:
- frequent trips to the litter box
- failure to use the litter box and urinating in unusual places
- straining to urinate with little urine expressed
- blood in urine
- depression, dehydration, lack of appetite, and sometimes vomiting
- crying when urinating or licking genital area excessively
Over the years, diet has been implicated as the cause of lower urinary tract disease, or more specifically, the cause of stone formation in cats; but in fact, urolithiasis (kidney or bladder stones) is not the most common cause of FLUTD. Historically, dietary ash has been associated with FLUTD, and there are still some people who believe this is the case. Ash does not cause FLUTD. As far back as the 1950s, research studied high ash diets as a possible cause of urethral blockage in cats. It was discovered that high ash diets can actually prevent blockage if the composition of ash is appropriate.
Ash is the measure of the total mineral content of a particular cat food. It refers to the inorganic portion of a measured food sample after a laboratory analysis in which the sample is burned at 600 degrees Centigrade for two hours. Ash is a necessary part of any nutritionally complete and balanced cat food because it contains calcium, phosphorus, sodium, potassium, magnesium, and manganese, among other minerals which are essential nutrients.
What researchers have recently determined is that the magnesium portion of ash may be important in certain forms of FLUTD. Some people believe that because magnesium is a component of ash, a low ash diet must be low in magnesium. This is not true. A diet that is low in ash could be deficient in calcium and still be high in magnesium.
Chemistry is the key to the dietary management of struvite, a mineral compound associated with some types of lower urinary tract disease. At a high pH, above 6.8, struvite crystals tend to form and bladder stones may occur. If the pH is below 6.5, the crystals are less likely to occur and the minerals are easily excreted in the urine.
Animals maintain their body's pH balance by excreting acidic or alkaline metabolites into their urine. A cat's urine can normally range from near 5.5 to nearly 8.0. Through careful formulation, diets have been developed that help cats produce mildly acidic urine with a pH of about 6.4.
The feeding schedule also influences the acidity of the cat's urine. After eating, cats tend to have what is known as an alkaline tide. The pH of the urine increases three to five hours after the cat eats and then, after several hours, returns to the acidic range. When cats are fed free-choice, this alkaline tide is minimized. The cat experiences little peaks and valleys because they are doing what most cats do - nibbling at their food over a period of several hours. The overall result is a lower urine pH especially if the diet is designed to allow acid urine.
As mentioned before, FLUTD can have several contributing factors, so no diet alone can claim to prevent FLUTD. There have been some claims that dry cat food causes FLUTD. Research has been unable to prove any causal connection between FLUTD and the form of a cat's food. Acidifying diets are not appropriate for all urinary tract problems. Following diagnostic tests, veterinarians should recommend a course of treatment.
Reducing the Risk:
Based on the current knowledge of FLUTD, here are steps that can be employed to help reduce the risk of a cat developing FLUTD:
- Provide fresh, clean water at all times. Keep the water in a non-tippable bowl and be certain that the cat is emptying the bowl by drinking and not playing with the water.
- Keep the litter box clean and easily accessible to the cat and also situate the box to provide privacy for the cat.
- Encourage the cat to exercise or play. This is especially important for indoor cats. Take time to play games with the cat and encourage the cat to play with toys that are safe.
- Feed cat food free choice.
- Keep the cat at its proper weight.
- Minimize stress factors such as sudden changes in environment, exposure to harsh weather conditions and emotional upsets.
- Schedule regular veterinary checkups.