Lower Urinary Tract Conditions in Cats

Apr 12, 2018

Feline Lower Urinary Tract Disease (FLUTD) is a common condition in cats. The lower urinary tract refers to the bladder and urethra (tube from the bladder to the outside), while the kidneys and ureters make up the upper urinary tract. Disease of the lower urinary tract may involve infections, crystal or stone formation, idiopathic (without any obvious underlying cause) cystitis, bladder cancer, or other conditions. Cats may be predisposed to these conditions through dehydration (especially when fed kibble only diets), stress, obesity, inappropriate diets, kidney disease, diabetes, or a host of other factors.

Many cats with lower urinary disease exhibit signs such as peeing outside of the litter box, peeing blood, or experiencing pain while urinating. Urinary disease may lead to complete urinary obstruction (blockage leading to inability to urinate), especially in male cats. This is a life threatening condition if not treated promptly. Many terms exist to describe lower urinary symptoms in cats including FLUTD, Feline Urologic Syndrome (FUS), and others.


Cats with urinary disease may exhibit one or many of the signs described below:

  • Blood in the urine
  • Urine with a strong odour
  • Pain when urinating (crying or vocalizing)
  • Straining to urinate, with or without urine production
  • Frequent or small volume urination
  • Excess licking around the penis or vulva
  • Over-grooming the abdomen over the bladder
  • Inappropriate urination outside the litter box (on the floor, in the tub, etc.)
  • Fine crystal/powder material in the fur around the opening to the urinary tract
  • Hiding
  • Reduced appetite

In late stages of disease, especially in males, obstruction may occur which may manifest as vomiting, weakness, collapse, and lethargy. Note that in some cats, obstruction is the first urinary sign that is noted.

Types of Urinary Disease

  • Stones (uroliths) and crystals (crystalluria) may form in the urinary tract. These may cause obstruction, but if not large enough to block the urethra they may produce significant inflammation and irritation to the bladder (cystitis) and urethra (urethritis). Sometimes very small stones accumulate, which may be called “sand”. Stones and crystals cause: physical irritation from moving and rubbing against the lining; damage to the normal mucous layer of the bladder; and irritation from urine which is outside the normal acidity/alkalinity balance. Crystals and stones form when urine is concentrated (high specific gravity), too acidic or basic, or contains too high a concentration of minerals such as calcium, magnesium, ammonium, or phosphate.
  • Feline Interstitial Cystitis (FIC), also termed “Feline Idiopathic Cystitis,” is a commonly seen inflammatory disease of the bladder resulting from stress, genetic factors, and other conditions that stimulate inflammation and damage to the bladder wall. Indoor cats with sedentary lifestyles, anxiety, or lack of stimulation are at highest risk. Risk factors also include obesity, concentrated urine, and poor diet. Urine from cats with FIC is sterile with no crystals or stones, however severe inflammation and pain is present. This is possibly the most common cause of lower urinary disease in modern housecats.
  • Urinary Tract Infections (UTIs) are not common in cats, especially young or male animals. When they occur, they may be present alone, or more commonly along with one of the other described conditions as a complicating factor.
  • Bladder cancer (usually Transitional Cell Carcinoma), though uncommon, can lead to irritated tissues around the growth, bleeding, or infection.
  • Congenital diseases (birth defects) such as malformed urinary tracts, misplaced ureters, underlying kidney diseases, or others may also occur.
  • Spraying” is not truly a urinary disease, but a normal behaviour of intact male cats or cats exposed to testosterone. This involves peeing a fine mist on vertical surfaces with the tail raised as a territorial marking tool.

“Blocking” or Lower Urinary Tract Obstruction

Blockage of the urinary tract of cats can be caused by any of the above conditions and may be preceded by any or none of the discussed signs. Male cats are overwhelmingly more likely to experience obstruction due to their long and thin urethras. A blockage may develop if the cat has stones/sand that move down from bladder or kidneys and lodge in the narrow urethra. It can also occur if a scar tissue ring forms, inflammation or infection causes the urethra to swell closed or spasm, or a mucus/blood clot plugs the urethra.

Cats with lower urinary obstruction often strain repeatedly and express little to no urine. They experience a lot of pain and may vomit or go into hiding. Cats may collapse and show extreme weakness in the late stages of disease. Additional signs may include howling while straining, distressed attitude, loss of appetite, and progression to inability to move. Within 48 hours of obstruction untreated cats may die of kidney failure or electrolyte disturbances. Potassium levels generally rise, and in extreme conditions these high levels may lead to stoppage of the heart. Bladder rupture may also occur, which is often fatal if not rapidly addressed.

This condition is extremely painful and life threatening — do not delay seeking veterinary care if you suspect this issue is occurring. This is a disease that requires emergent treatment—do not “wait until morning,” but present the cat to an emergency hospital as soon as possible.


Medical history collected from the cat’s caregiver and a full veterinary physical exam form the basis for diagnosis of lower urinary tract disease. The veterinary team may also perform a urinalysis, urine culture, X-rays, or ultrasound to diagnose and characterize disease. Blood work is often recommended to further assess kidney function, electrolyte levels, and rule out secondary or underlying disease. Some diseases, such as FIC or behavioural inappropriate urination, may be diagnosed based on the exclusion of other diseases or require advanced testing.


Depending on the situation, one or several of the below therapies may be most suitable. For any of the conditions named above, earlier intervention leads to an improved prognosis.

  • Pain medications and anti-inflammatories (use may depend on kidney function).
  • Antibiotics are used if a UTI is confirmed and are ideally based on culture and sensitivity results.
  • Urinary diets are frequently used as an adjunct or as a preventive measure; canned food is preferred due to high moisture levels.
  • Anti-spasmodic therapy may be added to relax the urethra, most often a drug called “prazosin”.
  • Different nutraceuticals may be considered. These include l-theanine, glucosamine, fatty acids, and complex carbohydrates to help support the protective lining of the bladder.
  • Environmental enrichment and stress reduction. This may include private areas that are quiet and free of inter-cat competition, playtime, pheromones, toys, extra dishes, clean litter boxes, perches, and scratching posts. Allowing cats an outside view can help entertain them (watching birds, weather, etc.) and helps alleviate boredom.
  • Surgery (cystotomy) may be necessary if the cat has large or multiple stones, especially calcium-based. Dissolution with diet is often tried first depending on the results of tests.
  • Unblocking is necessary if the urethra has obstructed. The goal of this procedure is to flush obstructing material out of the urethra and into the bladder. IV fluids are also given to normalize electrolytes and flush toxins from the bloodstream (urea, potassium, and creatinine primarily). This is a hospitalized procedure. Once the obstruction is removed and the bladder flushed thoroughly, a catheter is left in the urethra to allow the overstretched bladder to recover. Adequate pain medicine, anti-inflammatory therapy, and spasm reducing medications are essential. After unblocking, urine production is closely monitored and the vitals checked regularly while in hospital. Hospitalization is continued until it is confirmed urinations are occurring in the day or so following removal of the urinary catheter. Risk of re-blocking is highest in the week following the blockage as swelling and spasms continue in the urinary tract.
  • Drugs are available to help manage stress and anxiety and can be helpful during active illness to promote healing.
  • In rare cases, a surgery called “perineal urethrostomy” may be needed to shorten and widen the male urethra through removal of the penis. This is a salvage procedure that is generally only used as a last resort or in intractable obstruction due to high long-term risks of complications.


Stress Reduction
Reducing stress is very important as cats often develop urinary tract issues when they feel threatened, bored, or generally anxious. This may include increased playtime, removal of sources of anxiety, and stress diets or supplements. Increased enrichment is possibly the most important of these. Both FIC and behavioural issues are strongly tied to stress levels.

Diet and Water
Cats should always be fed a balanced feline specific diet. Moist (canned) food is preferred to kibble as it maintains hydration and minimizes mineral content.

Ask your veterinarian about urinary tract diets that are available—many of these are prescription only. Some are only meant to be fed short-term, others are well suited to lifelong feeding as a preventive. Diets may help dissolve or prevent stones and crystals, minimize stress and anxiety, promote weight loss, restore normal mucous barriers, and balance pH. Different diets may be chosen for different conditions; your veterinarian has information on various prescription (or potentially over-the-counter) options.

Fresh water should be made available at all times. Change it at least twice daily and encourage drinking. Some cats like water to be chilled, while others prefer it at room temperature. Large bowls and cat fountains may encourage drinking in some cats. Adding water to food is also a good option to increase intake.

Obesity and Exercise
Cats that are physically fit and receive sufficient exercise are less likely to develop urinary disease (and many other systemic issues). Restricting calories, regular exercise, and a careful nutrition plan can minimize risks of lower urinary disease or recurrence.

Litter Boxes
Clean litter boxes frequently and monitor closely for any unusual signs, particularly blood-tinged urine or a change in urine volume. Most cats prefer open boxes (though some may like a covered box), and as a general rule larger and shallow boxes are better. Avoid the use of strongly scented litter and ensure there are enough litter boxes. One litter box for each cat plus an additional box is a good starting point. Keep boxes physically separated and do not change locations frequently. Boxes should be in calm areas away from laundry machines, doors, and high traffic areas.

Elimination Behaviour
Observe your cat and pay particular attention to its elimination habits. Early signs of problems are similar to those associated with constipation (frequent straining). Peeing outside of the litter box, frequent trips to the box, and straining to pee are all causes for concern. If in doubt, contact your veterinarian.


Once cats have a urinary blockage, they are at higher risk of complications, including re-blocking, kidney damage and scarring of the urethra, or continued urinary signs. Special lifelong diets are often needed and medical therapy may also be required. Complications may also occur due to any urinary tract disorders. Your veterinarian will review the possible outcomes with you at the time of treatment.

In summary, urinary tract disease is common in cats and, if progressive, may lead to life-threatening blockage or other long-term complications. Always seek professional care promptly for any urinary tract issues.

Dr. Kathleen Cavanagh, Consulting Online Editor CVMA, BSc DVM MET
Dr. Matthew Kornya, Consultant, BSc, DVM, Resident ABVP      

January 29, 2018