Feline Lower Urinary Tract Disease (FLUTD)

Feline Lower Urinary Tract Disease (FLUTD) is not a specific disease, but rather a term used to describe conditions that result in inflammation of the bladder (cystitis) and/or the urethra (urethritis). These conditions may result in partial or complete obstruction of the urinary tract. Urinary obstructions are life threatening and require immediate veterinary attention.

Causes of FLUTD

The clinical signs for these urinary conditions are very similar and there may be more than one single cause. It’s often difficult or impossible to determine the underlying cause without doing further investigations. Many different diseases can affect the lower urinary tract and a number of cats develop a disease without any obvious underlying cause, this is known as Feline Idiopathic Cystitis (FIC).

Clinical Signs of FLUTD

Cats with FLUTD usually present with one or more of the following signs:

  • Dysuria – this term refers to difficult or painful urination. The cat may strain when trying to urinate and may appear painful e.g. vocalisation (crying/yowling).
  • Pollakiuria – this term refers to an increase in frequency of urination. Infection and inflammation of the bladder and/or urethra will cause irritation and increases the desire to urinate more frequently.
  • Haematuria – this term refers to blood in the urine. This can occur with infection and inflammation. Sometimes blood in urine may not be obvious and may only be detected when performing a urinalysis as the blood in urine may be microscopic.
  • Periuria – this term refers to urinating outside the litter box and urinating in inappropriate places. This can occur because of irritation, pain and inflammation causing the cat wanting to urgently urinate and therefore they may not have time to get to the litter box or outside.
  • Excessive Grooming – some cats will start to over groom themselves including licking and grooming around their perineum. This is a result of the pain and irritation of the bladder and urethra and can be severe enough to cause hair loss when they excessively groom.
  • Behavioural Changes – some cats may only show behavioural changes such as toileting changes (not using the litter box, frequency), aggression, irritation and loss of appetite.
  • Stranguria – this term refers to the obstruction to the urethra, meaning cats will strain in attempt to pass urine but will be unable to. Obstruction is most commonly seen in male cats do their urethra being longer and narrower than that of a female cat. Although obstruction is not common, if there are any signs it should be treated as an emergency. Refer to our Urethral Obstruction page for more information on this condition including signs and treatment.

Which Cats are most at Risk of FLUTD?

Because FLUTD is complex and may have multiple underlying causes, cats of any age, breed and gender can be affected by FLUTD, but the disease is more commonly seen in:

  • Middle-aged cats
  • Neutered cats
  • Overweight cats
  • Cats which take little exercise
  • Cats with little or no access outside
  • Cats on a dry diet

Underlying Causes of FLUTD

A number of different diseases may cause FLUTD but some of the more common causes include:

  • Urolithiasis – this term refers to bladder stones. The two most common stones are ‘magnesium ammonium phosphate’ (also known as ‘struvite’) and ‘calcium oxalate’. These two stones account for 80-90% of cases of urolithiasis, but other stones also may be seen. Urolithiasis generally accounts for around 10-15% of cases of FLUTD.
  • Bacterial Infections – Bacterial Cystitis (bacterial infection of the bladder) is the most common cause of lower urinary tract disease in many animals, but relatively uncommon in cats. It accounts for 5-15% of all cases of FLUTD. Bacterial Cystitis is more commonly seen in older cats.
  • Urethral Plugs – obstruction of the urethra in male cats may occur as a result of a ‘urethral plug’. This is an accumulation of proteins, debris and urinary sediment that cause a plug and therefore urine cannot pass. Other causes of obstruction include small bladder stones or swelling and spasm of the urethra (inflammation causes swelling of urethral wall).
  • Anatomical Defects – in some cases, there may be an anatomical defect in the lower urinary tract causing signs of disease. This most commonly occurs with a stricture affecting the urethra. If the urethra becomes damaged, during the healing process fibrous tissue may develop which can significantly restrict the diameter of the urethra.
  • Neoplasia – although this cause is uncommon, particularly in older cats with signs of FLUTD, the possibility of a tumour affecting the bladder or urethra needs to be considered.
  • Idiopathic Cystitis – despite the well-recognised causes of FLUTD, in the majority of cats with no specific underlying disease (no identifiable cause), these cats are classified as having ‘Feline Idiopathic Cystitis’ – a term that simply means inflammation of the bladder without a known cause.

Investigation of FLUTD Cases

In cats that display signs of FLUTD, especially where clinical signs are persistent or severe, it’s important to try identify the underlying cause. Common investigations include:

  • Urinalysis – this involves collecting a urine sample to examine microscopically. The veterinarian may also perform a bacterial culture to rule out bacterial infections.
    • The veterinarian may obtain a urine sample via Cystocentesis. This means collecting the urine using a very fine needle that is placed directly into the bladder.
    • This is a good way of collecting a sample as it is a sterile procedure and won’t be contaminated with bacteria from elsewhere.
  • X-Rays – the veterinarian may recommend taking x-rays of the bladder that can be particularly helpful in identifying a number of causes including determining if there is any presence of bladder stones, urethral stricture or tumours.
    • Taking x-rays will generally involve a sedation or general anaesthetic in order to keep the cat comfortable and to produce high quality images for interpretation.
  • Ultrasound – the veterinarian may also recommend an ultrasound examination of the bladder which can help identify bladder stones and/or thickening of the bladder.

Treatment of FLUTD

The treatment of FLUTD will depend on the underlying cause. In long-term management of FLUTD, increasing water intake and encouraging more frequent urination are good goals in all cases of FLUTD. This can be achieved by encouraging a wet diet (tinned or sachet) rather than dry foods, encouraging drinking (more water bowls, water fountains), encouraging exercise and using the type of litter and litter tray that your cat prefers.


Bacterinal Cystitis

Bacterial Cystitis cases usually respond well to appropriate antibiotic therapy. The choice of antibacterial drug will be made on the basis of the bacterial culture results. Because Bacterial Cystitis is uncommon in cats, antibiotics are generally only used when the veterinarian has a strong suspicion of bacterial infection or when indicated by the bacterial culture of urine sample.

Urolithiasis (Bladder Stones)

In cases where bladder stones are present, the veterinarian may recommend surgery to remove the stones depending on the severity. In some cases, stones (especially struvite) may be possible to dissolve with an appropriate prescription diet. These diets are available to order through the veterinary clinic and they are formulated to carefully modify the composition of the urine that helps dissolve existing stones as well as preventing the reoccurrence of stones. If there is presence of calcium oxalate stones, these cannot be dissolved with prescription diets and surgery is required if removal is required.

Urethral Plugs

In cases where urethral plugs are present, this is considered an emergency situation as these plugs cause obstruction. A blocked urethra can cause acute kidney failure within 2-3 days and therefore immediate veterinary attention is required to relieve the blockage. Urethral plugs are generally removed under an anaesthetic as the patient needs to be still for the procedure as well as keeping the patient comfortable and as pain free as possible. After the blockage is relieved, the patient is usually hospitalised for a period of time so the veterinary team can monitor their progress. Click here for more information on Urethral Obstruction in Cats.

To prevent the reoccurrence of urethral plugs, the veterinarian may recommend changing your cat’s diet to feeding a wet diet rather than a dry diet as this will encourage greater water intake and therefore more frequent urination. A prescription diet may also be recommended if crystals are often present in the urethral plug. These prescription diets are specially formulated to help dissolve crystals as well as preventing new crystals forming. It is also thought that many cats with urethral blockage may have underlying idiopathic cystitis (FIC) and so treatment recommendations for this disease should also be considered.

Urethral Strictures

In cases where a urethral stricture develops, surgery is usually required to correct the problem.  Urethral stricture cases can be difficult to manage, the success of the surgery is dependent on the severity of the stricture and its location.

Feline Idiopathic Cystitis

The underlying causes of Feline Idiopathic Cystitis (FIC) are not fully understood and management of FIC is complex. The best approach to managing cats with FIC is multimodal treatment which means making a number of changes to help minimise the recurrent episodes of FIC. The most effective management options are focusing on reducing environmental stress and increasing water intake.

Bladder Tumour - Transitional Cell Carinoma

Bladder tumours are rare in cats. In the rare instance a tumour is confirmed, the most common tumour seen is a transitional cell carcinoma, occurring mainly in older cats.  Often by the time clinical signs develop, the disease is quite advanced and surgical removal is rarely possible. A veterinarian may refer your cat to a specialist if chemotherapy is recommended which can help reduce the size of the tumour and improve quality of life. Prognosis is dependent on the individual cat and the severity of the tumour.