Pet Illnesses

Feline Urological Syndrome (FUS, FLUTD)

FLUTD is also known as Feline Urological Syndrome or Feline Cystitis. FLUTD has many causes, including infection, trauma, bladder stones, crystals, urethral obstruction or cancer.

The most frequent cause of cystitis or blood in the urine in cats is unknown- officially, this is called Idiopathic FLUTD (see below).

FLUTD can be obstructive (commonly known as `blocked’), or non-obstructive. Obstructive cases happen in male cats when a plug forms and lodges in their naturally long, thin urethra. Obstruction in female cats is rare.  Non-obstructive cases are more common, but obstructive cases are life threatening.

Obstructive cases can cause kidney failure
or death within 3-6 days of obstruction

Idiopathic FLUTD

Male and female cats prone to this are usually between 2-6 years of age. Clinical signs are usually pain on urinating, increased frequency of urinating, and blood in the urine. Urine is usually concentrated and acidic, and clinical signs usually subside in 5-7 days, unless signs lead to an obstruction. Recurrence is common, and episodes may decrease in severity and frequency over time.

A urine test is usually required to check for abnormalities, and sometimes, an additional test to see if bacteria is present in the urine is warranted. The vet will discuss what is required and what your options are. Treatment usually includes anti-inflammatories (for pain and inflammation), antibiotics (if an infection is suspected or proven by lab urinalysis) and prevention.

All cases need a thorough workup by a vet to determine the exact nature of the problem and the correct management plan to try and prevent re-occurrence.

Normal cat lowerCat fusMicroscope struvite


Affected cats feel the irritation in their urinary tract and have an urge to urinate (cystitis). Quite often, bacteria accompany the crystals increasing the level of discomfort. Cats suffering from FUS/FLUTD try to urinate more often than normal, often crying out whilst doing so. Owners may notice small drops of blood tinged urine in the litter tray.

The urethra in female cats is wider then in male cats. Unfortunately for male cats, their urethra is much narrower. Urinary crystals or "plugs" made of a mixture of inflammatory cells, thick mucous-like material (usually from inflammation of the bladder wall and/or crystals) can get stuck in a male cat urethra causing a blockage to the flow of urine. The male urethra is surrounded by small muscles, which sometimes spasm/cramp when there is a blockage or irritation in the urethra, thus compounding the initial blockage.

A “blocked” male cat is in a life threatening situation. The kidneys keep making urine despite the fact that the cat can not pass it. The bladder gets bigger and bigger, and the kidneys start to get a huge amount of back pressure of urine applied to them. There is a dramatic rise in the amount of potassium in the bloodstream as a result of this, which causes an irregular heartbeat. Death can occur within 24-36 hours of a complete blockage.


Although there is no single cause of FLUTD, various risk factors have been determined that predispose cats to the disease:

Factors that cause high urine levels of magnesium

Factors that contribute to an alkaline urine pH


Female cats do not usually present with a blockage. Urine samples are examined to determine the exact nature of the crystals as not all cases are Struvite. The cat is placed on antibiotics (if bacteria are present), mid anti-inflammatories to lessen the irritation and special prescription diets e.g. Hills Feline S/D (struvite diet) or Royal Canin Urinary to dissolve the crystals by changing the urine pH. If the cat has Oxalate crystals, it usually goes onto Hills X/D diet.

Water intake has to be increased so tin foods are preferable to dry foods.

Blocked cats need surgery to relieve the pressure on the kidneys. If a cat is in serious trouble, a vet may place a large needle directly  into the bladder to suction out as much urine as possible, thus removing the back pressure on the kidneys and “buying some time” prior to surgery. Once stabilised, the cat is anaesthetised and a smooth urinary catheter passed into the tip of the penis in an attempt to flush the blocked crystal backwards into the bladder and the bladder is emptied.

Some vets like to leave the catheter in place for 1-2 days to prevent a re-occurrence of the blockage. Other vets like to remove the catheter to try and minimise trauma to the sensitive ling of the urethra. 

Occasionally, male cats can be so severely blocked that it is not possible to pass a catheter into the bladder. These cases need to have an operation to change the plumbing so they urinate through a much wider hole. This operation is called a perineal urethrostomy. This is a rare operation to perform these days with the advent of the special preventative diets from Hills.


Tips on Transitioning Food

Generally introduce a new food over a 7 day period for dogs and 4 weeks for cats. Mix the new food with the old food, gradually increasing its proportion until only the new food is fed.

If your pet is one of the few that doesn't readily accept a new food, try...

This is important because the success of treatment depends to a large degree on strict adherence to the new food.

The Risks of Excessive Salt Intake in Your Pet

Salt can be added to products to improve their taste or to try and encourage more drinking.

Too much salt in your cat's diet could put her at an increased risk of health problems such as heart diseases and higher blood pressure.

Excess salt can stimulate the progression of kidney disease, even before it can be detected, particularly in older cats who may be in the early stages of disease but their owners are not aware of it.