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.