Print Friendly

Feline urological syndrome (F.U.S.) is a common problem which affects cats. Its exact cause is still unknown. Diet, inadequate water intake, bacteria, viruses, and stress may all be involved.

Symptoms include frequent straining to urinate small amounts or no urine at all. Failure to use a litter box, urinating in a sink or bathtub, and blood-tinged urine are also warning signs.

The word “syndrome” refers to a group of symptoms or signs, which can appear individually or in a combination. Four of the more common disorders that can be associated with feline urological syndrome are:

Cystitis: inflammation of the lining of the wall of the urinary bladder. This often results in an accumulation of blood, mucus, and cellular debris in the bladder.

Infections: the blood, mucus, and other debris associated with inflamed tissue is a perfect place for bacterial infections.

Urolithiasis / Urethral Blockage: crystallization of minerals (struvite or others) and irritation of the lining of the bladder and the urethra resulting in the formation of clay-like material which can plug up or block the urinary outflow tract. This blockage is life threatening if not relieved.

Uremia: a life-threatening accumulation of poisonous wastes in the bloodstream. The inability to urinate causes a full bladder and this prevents the kidneys from discharging poisonous wastes from the body. Unless the blockage is promptly removed the cat will suffer a painful death. Straining to urinate, depression, weakness, vomiting, and collapse are the signs which, if uncorrected, lead to coma and death.

What cats get F.U.S.?

If occurs in cats of all ages. Male and female cats are both susceptible to the formation of the sand-like crystals and stones. Males are more apt to be affected by urethral plugs because females have shorter, wider urethras. Studies suggest that neutering or surgical sterilization does not cause a reduction in the size of the urethra in male cats.


Although many factors contribute to this disease syndrome, the exact cause of F.U.S. is still unknown and this complicates the treatment procedures. The formation of crystals that lead to stones or plugs, for example, are a result rather than a cause of the problem. Medication and a change in diet may help to minimize the problem. Some cases of F.U.S. may also require surgical or professionally applied procedures. Please do not attempt home treatments or delay contacting a veterinarian…a full bladder can easily be ruptured.

Avoiding the syndrome

Although the exact causes of F.U.S. are not yet fully known, here are some preventive considerations based of current knowledge.

Fluids: Be sure to provide plenty of fresh water, change it at least twice daily, and try to encourage drinking. If you have any doubts about your pet’s water consumption, please consult your veterinarian.

Diet: Be sure to feed your pet a complete and balanced diet. Cats are not big water drinkers. Sometimes adding canned food to the dies is enough to prevent most signs of F.U.S. disease. Be careful about feeding table scraps and treats. If in doubt, ask your veterinarian. Your veterinarian may recommend a special diet if your cat has had previous problems.

Obesity and Exercise: cats that are fit and trim are less susceptible to F.U.S. and other ailments.

Litter Box: Be sure to clean it often and watch for any unusual deposits particularly blood-tinged wastes.

Other Considerations

Observe your pets. Play particular attention to your cat’s elimination habits. Early signs of F.U.S. are similar to those associated to constipation straining. If you suspect F.U.S. or other abnormal conditions, seek professional help or advice as quickly as possible. Prompt treatment increases the likelihood of success, reduces suffering, and lessens medical bills.


A number of studies are now underway to help gain additions insight into F.U.S. In addition, the College of Veterinary Medicine and the University of Minnesota has established a special center for F.U.S. research.

In the meantime, prompt detection, early treatment, and long-term follow-up management remain the best therapy.

Published by the American Hospital Association
Copyright 1990