Feline lower urinary tract isease (FLUTD) is a term that is used to cover many problems of the feline urinary tract, including stones and cystitis. The term feline urologic syndrome (FUS) is an older term which is still sometimes used for this condition. The condition can lead to plugged-penis syndrome also known as blocked cat syndrome. It is a common disease in adult cats, though it can strike in young cats too. It may present as any of a variety of urinary tract problems, and can lead to a complete blockage of the urinary system, which if left untreated is fatal. FLUTD is not a specific diagnosis in and of itself, rather, it represents an array of problems within one body system.