Feline lower urinary tract disease (FLUTD) is not a single disease process. Rather, it is an umbrella term used to describe a range of disorders that affect the lower urinary tract in cats and is thought to affect approximately 1 to 3 percent of cats annually (International Cat Care, 2018). The clinical signs of all these disorders are very similar and without further investigation, it is not possible for the veterinary surgeon (VS) to diagnose the specific underlying condition.
Risk factors for lower urinary tract disease
Due to the variety of underlying causes, cats of any age, breed and gender can suffer with FLUTD. However, risk factors for development of FLUTD have been identified (International Cat Care, 2018), including cats who are:
- Middle-aged
- Overweight
- Neutered
- Indoor only
- Inactive
- Fed a dry diet
- Suffering stress
Clinical signs and underlying causes
Clinical signs of FLUTD include (Gear, 2023):
- Dysuria – difficulty and pain passing urine
- Pollakiuria – abnormal frequency of urination and passing a very small amount of urine
- Haematuria – blood in the urine (Figure 1)
- Stranguria – painful urination characterised by slow drips of urine
- Periuria – urinating outside of the litterbox in inappropriate places
Some common causes of FLUTD include:
Feline idiopathic cystitis (FIC)
FIC is the most common cause of FLUTD, responsible for around 55 to 65 percent of cases (Sparkes, 2018) and is a complex condition with mechanisms that are not fully understood. FIC is a condition that is diagnosed once all other potential causes have been excluded, so thorough investigations must be performed in order to rule out all other possible causes.
Urolithiasis
Urolithiasis is the medical term for bladder stones and may affect as many as 25 percent of cats with FLUTD (Forrester and Towell, 2015). The two most common types of uroliths in cats are magnesium ammonium phosphate (struvite) and calcium oxalate (Grauer, 2015).
Bacterial infection
Bacterial cystitis is rare in cats, accounting for around 1 to 8 percent of FLUTD cases (Heseltine, 2019) and tends to be seen in older cats.
Urethral obstruction – plugs, spasm, uroliths
Urethral plugs form due to an accumulation of protein, cells and crystals in the urine which combine to create a plug, causing obstruction in the male urethra. Urethral muscle spasm can occur secondary to severe inflammation and irritation, leading to urinary obstruction. Small uroliths can pass from the bladder into the urethra and lodge, causing obstruction.
Neoplasia
Neoplasia is an uncommon cause of FLUTD (Heseltine, 2019). Transitional cell carcinoma is the most common bladder neoplasia.
Investigations and diagnosis
The work-up for many cats with lower urinary tract signs will follow a similar approach. Thorough collection of clinical history is important as the VS needs to know which clinical signs the owner is seeing, alongside the chronicity and pattern of these signs: for example, whether the episodes are intermittent or continuous. One important area to question owners on is the cat’s defecation habits: dysuria and dyschezia can be easily confused because the cat will adopt a similar posture for both.
The owners must be questioned on the cat’s home environment and lifestyle to establish whether these may be contributing factors. Has there been any change to routine or anything that may be causing stress, for example a new pet in the household or a house move? Collecting information on dietary history is also necessary to determine if they are fed a dry or wet diet.
A complete physical examination should be performed on every cat, and it is important not to focus solely on the urinary tract. All body systems should be assessed in a logical manner to determine if any comorbidities or non-urinary diseases are present that could cause or influence the clinical signs.
A key investigative test in cats with urinary signs is urinalysis. Basic urinalysis, including dipstick, urine specific gravity and sediment examination, can be performed on a free-catch/voided sample, which is collected using non-absorbable litter. If a urine culture is to be performed, a sterile urine sample is required, and this may be obtained by urethral catheterisation or cystocentesis. The latter is the gold standard and is usually simpler to perform in cats than catheterisation as it can often be performed conscious.
Haematology and biochemistry are often performed to determine if there is any renal damage resulting from FLUTD, and also to check the overall health of the cat. Diagnostic imaging is performed as part of the diagnostic work-up. Plain and/or contrast radiography may be performed and may highlight urolithiasis, strictures or mass lesions. Ultrasonography allows for the examination of bladder size and wall structure along with renal architecture and size. Depending on diagnostic imaging findings, sampling of any lesions may be performed.
Treatment of feline lower urinary tract disease
If a cat with FLUTD presents with an obstruction and is unable to urinate, this is a medical emergency. These cats require immediate stabilisation and likely urethral catheterisation to relieve the blockage.
In cases of unobstructed FLUTD, the treatment will largely depend on the underlying cause, but there are some general approaches that can be applied in most cases to reduce risk factors. Encouraging an increased water intake, for example through the use of water fountains or feeding a wet diet, will result in more frequent urination. In addition to this, implementing a weight loss plan is recommended.
Owner education is vital in cases of FLUTD. Nurses are optimally placed to discuss methods of minimising stress while working with owners to optimise the home environment and cat’s facilities. To ensure owners are meeting their cat’s needs, the five pillars for a healthy feline environment (Ellis et al., 2013) can be used to structure conversations between nurses and owners. The five pillars are to provide:
- A safe place
- Multiple and separated key environmental resources (food, water, toileting areas, scratching areas, play areas and resting/sleeping areas)
- Opportunity for play and predatory behaviour
- Positive, consistent and predictable human–cat interaction
- An environment that respects the importance of the cat’s sense of smell
An approach to environmental management in cats with FLUTD, termed multimodal environmental modification (MEMO), has been demonstrated to have a positive effect on stress reduction in these cats (Buffington et al., 2006) and is another resource that can be used when counselling owners.
Support can be initiated during the initial consultation or discharge appointment, and continued with follow-up telephone calls and nurse clinics. It is important to consider which follow-up methods would best suit the cat; if travelling to the clinic is going to cause stress for the cat, telephone or video call follow-ups may be more appropriate.
Treatment options for specific causes of FLUTD
FIC
As the mechanisms of FIC are not fully understood, successful management is complex and multimodal. Implementation of the general approaches discussed above are important for cats with FIC. Additional management options include nutraceuticals. Glycosaminoglycan (GAG) supplements, for example Cystophan or Cystaid (Figure 2), may be prescribed by the VS to support the GAG layer in the bladder mucosa. However, in one study of cats with FIC there was no significant difference between the cats who received these supplements and those who did not, therefore their use may be controversial (Gunn-Moore and Shenoy, 2004). Alpha-casozepine, for example Zylkene, is a natural milk powder nutraceutical that acts on the brain through the same neurotransmitter as benzodiazepines, producing a calming effect, and may be used to reduce the stress element of FIC (Debé, 2013).
Due to the inflammation present during episodes of cystitis, the cat can be in pain or discomfort. It is important that appropriate analgesia is prescribed and if renal parameters are normal on biochemistry, non-steroidal anti-inflammatories are a suitable option (Figure 3).
Urolithiasis
The management of urolithiasis will depend on the type of urine crystals and stones that are present. Some types, for example struvite, may be managed with dietary change. These diets work by altering the composition of the urine with the aim of dissolving existing stones and preventing the formation of new stones.
Other types of urolith, for example calcium oxalate, can only be managed surgically, and cystotomy would be the treatment option of choice to manage existing stones. To reduce the risk of recurrence of calcium oxalate urolithiasis, it is important to encourage an increased water intake (Grauer, 2015).
Bacterial infection
Antibiotics are prescribed to treat bacterial infection, and the agent prescribed should be based on culture and sensitivity results.
Neoplasia
In cases of neoplasia, options may include surgical resection or chemotherapy but will depend on the clinical condition of the cat and the stage of the cancer, in addition to considerations including the cat’s welfare and quality of life, owner wishes and any financial limitations.
