Feline urologic syndrome, or FUS, is a common urinary tract disorder of cats. The syndrome may be manifested in cats as bloody urine, difficult urination, inappropriate urination and urinary blockage. Treatment must be directed at the underlying cause.
Common name: Feline urologic syndrome (FUS)
Scientific name: Feline urologic syndrome (FUS), Feline lower urinary tract disease, Feline idiopathic lower urinary tract disease, Sterile cystitis.
The average age of diagnosis for feline urologic syndrome is 3.5 years. Males appear more at risk than females.
The incidence of feline urologic syndrome is 0.5 percent to 1 percent of the cat population every year.
There is no geographic predilection for feline urologic syndrome.
Clinical signs (primary, most to least frequent, scientific term, synonyms)
Dysuria (painful urination), Pollakiuria (frequent urination), Stranguria (straining to urinate), Hematuria (blood in urine).
Clinical signs (secondary, most to least frequent, scientific term, synonyms)
Urinating outside the litter box, Hiding or seeming less social and more irritable.
Causes (scientific, common term)
The cause of FUS is unknown. Viral. Stress seems to play a role.
Organ systems affected (most to least affected)
Urinary bladder, Urethra.
Physical examination, Urinalysis, Urine culture to rule out bacterial infection, Radiographs (X-ray), Ultrasound.
Urinary tract obstruction, Urinary tract infection, Bladder stones, House soiling (behavioral problem).
Feline urologic syndrome (FUS) is a commonly diagnosed disorder in cats that is actually a group of clinical signs with varying or unknown causes. Cats with FUS may show evidence of painful urination, more frequent urination and blood in the urine and may urinate outside the litter box, often in a cool, clean place such as the bathtub or sink.
The average age of diagnosis for FUS is 3.5 years, and the incidence rate is 0.5 percent to 1 percent. Males appear more at risk than females. The cause of FUS is not known, though stress seems to play a role. Uncomplicated FUS, though uncomfortable, is not life-threatening alone. However, some cats can develop a urinary tract obstruction or blockage, which is a medical emergency.
Uncomplicated FUS usually resolves on its own in 4 to 7 days. During this time, however, the cat may be exceptionally uncomfortable. The cat's environment should be assessed for possible stressors, and if possible, these should be addressed and eliminated. Special wet and dry feline diets are available under recommendation from a veterinarian, which may help control the syndrome. Wet-food diets have the added benefit of increasing water intake, potentially making urine more dilute.
However, if the cat is accustomed to dry food, the change to wet food should be done gradually and the dry food not fully eliminated until the episode resolves, as a change of diet can be stressful. The most important aspect of home care is close monitoring to make certain the cat is able to pass urine. If no urination (or minimal urination) is seen for 12 hours, the cat must be taken to a veterinarian immediately to rule out a life-threatening condition such as a urinary tract obstruction.
A veterinarian examining a cat with clinical signs consistent with FUS will first palpate, or feel, the urinary bladder through the abdominal wall to ensure the cat does not have an obstruction. An obstruction would result in a large firm bladder that does not empty.
Initial diagnostic tests may include urinalysis and urine culture to rule out urinary tract infection and X-rays or ultrasound of the bladder to rule out stones. The veterinarian may prescribe a painkiller to relax the urethra or, in some recurrent cases, an antianxiety medication. A special diet may also be prescribed. If either a primary or secondary bacterial infection is suspected, antibiotics may be prescribed. Uncomplicated FUS does not typically involve bacterial infection.
If FUS-like clinical signs last for more than 1 week, the cat should be examined by a veterinarian. A cat that has not urinated or urinated only a small amounts during a 12-hour period must see a veterinarian immediately to rule out life-threatening urinary tract obstruction.
Most uncomplicated cases of feline urologic syndrome resolve on their own in less than 7 days, though recurrence is common. Diet may help reduce recurrence.
Lekcharoensuk, C., Osborne, C.A., and Lulich, J.P. Epidemiologic Study of Risk Factors for Lower Urinary Tract Diseases in Cats. JAVMA, May 2001, Vol 218, No. 9: 1429-1435.
Osborne, C.A., Kruger, J.M., Lulich, J.P., and Polzin, D.J. Feline Idiopathic Urinary Tract Disease. In: The 5-Minute Veterinary Consult. Philadelphia: Lippincott Williams & Wilkins, 2004; 456-457.
Andra Gordon-Gatica, DVM
Steven Hansen, DVM, MS, MBA
© 2007. The American Society for the Prevention of Cruelty to Animals (ASPCA)