Feline Lower Urinary Tract Disease (FLUTD)

Feline Lower Urinary Tract Disease (FLUTD)

Inflammation of the lower urinary tract is one of the most common reasons why cats see a veterinarian.

FLUTD is a set of diseases that manifest similar symptoms, but may have different causes. The final diagnosis is made on the basis of a thorough history, a detailed clinical examination and additional tests, such as a general urinalysis, ultrasound, and/or X-ray.

As cats have very complex personality, the owner should observe any change in behaviour that deviates from everyday standard.

The most common symptoms of the lower urinary tract inflammation in cats are as follows:

  • Painful urination (stranguria),
  • Small amounts of urine (urinary dribbling),
  • Frequent attempts to urinate,
  • Vocalisation,
  • More frequent cleaning of the genital area,
  • Haematuria,
  • urinating outside the litter box (but usually near the litter box),
  • Change of habits and behaviours of the cat (you are no longer able to keep track of what your cat is doing),
  • Decrease in appetite.

Lower urinary tract inflammation in cats is a set of disease entities that can manifest similar signs.

The causes of FLUTD in cats can be divided into the following categories:

  1. Congenital defects (mainly diagnosed in young cats)
  2. Tumours (mainly found in older cats)
  3. Urinary tract infections
  4. Urolithiasis
  5. Feline interstitial cystitis (FIC)

The causes in the first and second categories occur most rarely.

Urinary tract infections in cats

Urinary tract infection is the cause of only about 10–15% of lower urinary tract inflammations. The result of a urine culture obtained by bladder aspiration with antibiogram constitutes the basis for antibiotic use.

Special focus should be made on urolithiasis and feline interstitial cystitis.

FLUTD can cause urethral obstruction, which can lead to irreversible changes in the cat’s health and even be life-threatening.

Urethral obstruction can cause not only the formation of a stone, but also a mucus plug or the swelling due to inflammation of the urethra (functional obstruction).


The formation of urinary stones in the urinary system (most often in the bladder) occurs as a result of the supersaturation of urine with minerals. The pH of urine which affects solubility of the stones plays a key role in this process.

Two types of urolithiasis are most commonly diagnosed in cats:

  • The first one is ammonium-magnesium phosphate lithiasis (struvite lithiasis). High magnesium content in the diet affects struvite formation. However, what plays the most important role is the alkaline pH of the urine. This type of lithiasis is more common in female cats, usually at a young age. The deposits are located primarily in the urinary bladder. Breeds predisposed to this type of lithiasis include European Longhair and Ragdoll cats.
  • The second type is calcium oxalate nephrolithiasis induced by acidic urine reaction. This is more common in middle-aged and older male cats. The predisposed breeds include Siamese, Burmese, Himalayan, Persian, Devon Rex, and Ragdoll cats.

A cat showing signs of lower urinary tract problems obviously requires immediate intervention by a veterinarian. The extent of treatment depends on the clinical condition of the patient and the diagnosis. When providing assistance in urethral obstruction, time is of the essence.

The procedure that patients with FLUTD should follow at home is to increase water intake (20–50 ml/day) to reduce urine density. It is necessary to adjust the diet accordingly. As is well known, it is difficult to negotiate with cats as they usually have their own way of eating and resist if you try to change their diet. Therefore, supplements available on the market which do not affect the pet food used so far are valuable. It is good if the food is moist. In the course of struvite stones, DL-methionine is used to acidify the urine (the urine pH should be 6.5). So far, no pharmacological method to dissolve oxalate stones has been developed. To prevent the recurrence of stones, it is recommended to modify the diet after surgical removal of the stones and maintain a urinary pH above 6.2 using, for example, potassium citrate.

Feline interstitial cystitis (FIC)

Feline interstitial cystitis (FIC) is the most frequent cause of FLUTD in cats. No clear cause of this disease has been found yet. It is suspected that it is caused by increased activity of the sympathetic nervous system while that bladder changes are merely a consequence of this disease. FIC is a groups of symptoms affected many factors, such as obesity, poor nutrition, and low activity. However, STRESS plays a key role. The final diagnosis of FIC is based on the exclusion of other causes (so-called diagnosis by exclusion). The treatment of FIC consists primarily in stress reduction. In particular, multimodal environmental modification (MEMO) should be introduced. In this respect, pheromone preparations and change in the habits of the owner are helpful. 

FLUTD in cats cause damage to the glucosaminoglycan (GAG) layer of the bladder wall. GAG is a component of the bladder epithelial mucosa. GAG deficiency probably leads to exposure of the urinary tract epithelium, allowing it to come into contact with urinary components. Glucosamine improves the tightness of the bladder wall and protects it from toxins and bacteria. It also has an indirect anti-inflammatory and analgesic effect. The second important remedy used in FLUTD therapy is cranberry. Cranberry hinders adhesion of bacteria to the bladder wall and makes their colonisation more difficult.

Both cranberry and the DL-methionine mentioned above are found in dr Seidel treats for a healthy urinary tract.

FLUTD often causes frustration of the pet owner, the doctor and, above all, the patient itself. The successful treatment depends not only on the correct diagnosis, but also on the cooperation between all parties. To reduce relapses, the patient needs to change its habits and at the same time its owner may need to “reorganise their life.” The problem is broader, extending far beyond the purely medical scope.

To reduce tension and stress in cats, you can use a preparation with calming pheromone equivalents, such as dr Seidel electric adaptation vaporiser.

You may also need to consult a behaviourist.

Ilona Blanc, Veterinary Surgeon, Specialist in Dog and Cat Diseases

9 February 2021