Veterinary Internal Medicine Nursing

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All about feline lower urinary tract disease

Laura Jones

Feline lower urinary tract disease, or FLUTD, is a common condition causing stranguria in cats.

These cases can be really challenging to manage (anyone else always feel super sorry for these poor stressy bladder cats in the hospital?!) but they are so rewarding to nurse - and we can do a lot to support them long term, too!

In this post, I’m going to be talking you through what FLUTD is, how it is managed, and what we can do to nurse and care for these patients.

What is Feline Lower Urinary Tract Disease?

FLUTD is not a disease itself, but a spectrum of different diseases affecting the lower urinary tract. There are several causes of FLUTD, including:

  • Feline idiopathic cystitis (FIC)

  • Urolithiasis

  • Urethral spasm

  • Mucous plug

  • Bacterial cystitis

  • Urethral strictures

  • Neoplasia

  • Primary behavioural disorders

The most common of these causes is FIC, which we’ll be focussing on in detail in this post. You can also read more about the other causes in last week’s stranguria post.

The Lower Urinary Tract

To understand how FLUTD affects our patients, we first need to recap and understand the structure and function of the urethra and urinary bladder. 

This is particularly important in FIC, as these complex and poorly-understood neurological interactions between the brain and bladder are key in the disease’s development.

The Bladder

The urinary bladder is divided into three regions - the apex, body and neck, and the wall of the bladder is divided into several layers:

  1. The muscle layer (detrusor muscle) - which allows voiding

  2. The middle, submucosal layer - which is formed of connective tissue

  3. The inner mucosal layer - which is lined with urothelium (our transitional epithelial cells that stretch as the bladder fills with urine)

  4. The GAG (glycosaminoglycan) layer covers the bladder wall. This is a protective layer, and serves to prevent bacterial adhesion to the bladder wall, and prevents the urine from damaging the urothelium layer and causing inflammation.

Beneath the GAG layer is the bladder lumen, filled with urine. The bladder is supplied by sensory neurons, providing vital information about the bladder to the nervous system.

The Urethra

The urethra in male cats has a penile compartment and pelvic compartment and its function is controlled by 2 muscles:

  1. The internal urethral sphincter covers the bladder neck and cranial urethral. This is a smooth muscle and functions to create tone and resistance.

  2. The external urethral sphincter encircles the caudal urethra. This is a skeletal muscle and is responsible for voluntary continence.

Note that the sphincters are formed of different muscle types - when might this be important in treating and managing FLUTD?

A variety of muscle relaxant medications may be prescribed in the management of FLUTD - such as dantrolene and prazosin. These work on different muscle types; prazosin is a smooth muscle relaxant, and dantrolene is a skeletal muscle relaxant. This means they primarily exert their effects on different urethral sphincters.

Feline Idiopathic Cystitis

FIC is an inflammatory disease of the lower urinary tract with no obvious underlying cause. It’s a complex and still relatively poorly understood condition, and is thought to be similar to interstitial cystitis in people. 

FIC accounts for approximately 2/3rds of all FLUTD cases, and cats may present with or without an acute urethral obstruction.

Causes

Though the exact cause of the condition is unknown, a number of abnormalities have been identified in cats with FIC. These include:

  • An inappropriate hormonal/sympathetic nervous system response to stress

  • Alterations to the neurons in the bladder, resulting in ‘neurogenic inflammation (where activation of C-fibres in the peripheral nervous system results in inflammation, rather than due to the immune system)

  • Depletion of the protective glycosaminoglycan (GAG) layer lining the bladder

These changes suggest that FIC is the result of complex interactions between the bladder and brain and that certain cats are more susceptible to developing FIC when exposed to stressful triggers. 

Risk Factors

Several risk factors for the development of FIC have been identified, including:

  • Inactive lifestyle

  • Limited or no outdoor access

  • Low water intake (resulting in concentrated urine)

  • Obesity / high bodyweight/condition score

  • Having to use a litter tray indoors

  • Acute stressors (e.g. building work, house move, new baby, new pet)

  • Chronic stressors (e.g. multi-cat household with conflict between cats, litter tray placement and maintenance, conflict with cats outside of the household)

Urolithiasis

Urolithiasis (the presence of stones within the urinary tract) is the second most common cause of FLUTD, and can also affect the upper urinary tract. The two most common uroliths seen in cats are struvite and calcium oxalate, but other specific stones may be present in cats with underlying diseases (e.g. ammonium biurate uroliths in cats with portosystemic shunts).

Struvite

Around 50% of feline uroliths are composed of struvite. In cats, these are sterile (not associated with a urinary tract infection) in 95% of cases.

Several factors can increase the risk for struvite formation, including:

  • Urine pH - struvite forms in alkaline urine

  • Dietary factors - feeding diets high in magnesium, phosphorus, sodium, calcium, chloride and fibre 

  • Proteinuria - which can promote struvite crystallisation

  • Infection - with urease-producing bacteria, which make the urine more alkaline

Calcium Oxalate

Factors involved in calcium oxalate urolith formation are not completely understood, but we do know that they form in acidic urine supersaturated with calcium and oxalate. 

This can occur due to hypercalcaemia, increased dietary oxalate intake, and decreased concentrations of calcium oxalate inhibitors, such as citrate and magnesium.

Dietary factors can also play a role - the frequency of calcium oxalate urolith diagnosis has increased dramatically over the last 30 years (from 10% to 41% at the Minnesota Urolith Center). We suspected this is due to the increased availability and use of urine acidifying diets over the past 30 years.

Risk Factors

Because FLUTD is a diverse syndrome encompassing several different diseases, cats of any age, breed and gender can develop FLUTD. However, the disease is generally more common in:

  • Neutered cats

  • Inactive cats

  • Overweight cats

  • Indoor cats

  • Cats being exclusively fed dry food

Male cats are more likely to develop FIC and calcium oxalate uroliths, whereas female cats are more likely to develop struvite uroliths. 

FIC usually affects younger-to-middle-aged cats, whereas conditions such as UTIs and neoplasia are usually seen in older cats.

Clinical Signs

Cats with FLUTD generally present with:

  • Dysuria

  • pollakiuria 

  • inappropriate urination

  • Haematuria

  • Stranguria

  • +/- signs of urethral obstruction

As stress plays such a large role in FLUTD, stress-associated diseases or signs may also be present, including behavioural abnormalities, gastrointestinal signs and dermatological signs (e.g. overgrooming, particularly of the ventral abdomen).

Clinical History Collection

Collecting a thorough history is vital in cases of FLUTD, and the veterinary nurse is ideally placed to do this.

Due to the association with stress in this disease, our histories should include questions about the home environment and cat’s lifestyle, as well as general questioning about their urination and any systemic signs.

Collecting the patient signalment is also important in distinguishing different causes of FLUTD - for example, an older cat having their first episode of urinary tract signs is unlikely to have FIC, but more likely to have a UTI.

Diagnosis

Diagnosis can be challenging in the FLUTD cat. We need to identify an underlying cause for the FLUTD, and if one cannot be identified, we are essentially left with FIC as a diagnosis of exclusion.

Common tests performed in the FLUTD cat include:

  • Biochemistry and haematology, to identify any azotaemia or other abnormalities. This is especially important in an obstructed cat due to the risk of an acute kidney injury.

  • Urine analysis, including chemistry strip, specific gravity, urine protein:creatinine ratio, sediment examination and bacterial culture. This is performed to identify urinary tract infection or inflammation and narrow down our list of causes of FLUTD.

  • Diagnostic imaging, such as abdominal ultrasound and/or contrast radiography of the urinary tract to identify masses, strictures or stones.

Treatment

The specific treatments required will vary depending on the cause of the FLUTD. For example, an older cat with bacterial cystitis and a UTI will require treatment with appropriate antibiotics, depending on urine culture results.

What if my Patient is Blocked?

If the patient is obstructed, emergency relief of the obstruction must be performed.

Consider the type of catheter you’re using for this - ideally use one suitable for both unblocking and leaving in situ, if possible. If the patient requires a catheter to be left indwelling, a long, soft, flexible atraumatic one with both side and end-holes is preferred. Stiff, rigid catheters used for unblocking can cause trauma to the urinary tract if left in situ for longer periods. 

Treatment of the blocked cat in addition to relieving the obstruction includes:

  • Providing appropriate fluid therapy

  • Correcting acid/base and electrolyte abnormalities

  • Monitoring for post-obstructive diuresis (where large volumes of fluid and electrolytes are lost as urine output increases after the obstruction is relieved)

  • Providing appropriate analgesia and regular pain assessment

  • Other specific treatments like muscle relaxants (discussed later)

  • Antibiotics if necessary based on urine culture results

  • Urinary catheter management if one has been left indwelling

Surgical Intervention

Patients with repeated or complex obstructions may require surgical intervention. This is usually achieved with a perineal urethrostomy, a surgical procedure where the penis is removed and the urethra is widened and shortened to allow easier urination.

It is considered a salvage procedure and is not without risks - such as infection and stricture formation. The first two weeks of aftercare are also often challenging for an already quite stressy cat, as the patient will generally need periods of cage rest, can’t have cat litter in their tray, and will need to keep a large Elizabethan collar on at all times.

Medical Management

All patients, regardless of whether they present with an obstruction or non-obstructed, should have medical management strategies put in place to prevent their signs from recurring. 

This should be a multi-modal treatment approach including behavioural and medical therapies alongside dietary adjustments.

Medication

Medical therapies are generally not required for simple cases of FIC but are required for obstructed patients, other causes of FLUTD, or in patients with severe, chronic or recurrent FIC episodes. Medications include:

  • GAG replacers, to replenish the depleted layer in the bladder lining. These contain glucosamine & hyaluronic acid, which are the building blocks of GAGs. Many also contain l-tryptophan, a serotonin precursor, to minimise stress. 

  • Analgesia is a key part of treatment, to reduce bladder inflammation and pain, minimise urethral spasms, and minimise stress. Usually, opioids are used initially. NSAIDs are also beneficial in these patients to relieve bladder inflammation, but should only be started when normal renal function has been confirmed.

  • Many other medications have been used in FLUTD patients, including antispasmodics and muscle relaxants. These may be useful in obstructed patients to help relieve urethral spasm, but there is no evidence to suggest they are beneficial in cats with FIC.

Nutritional Management

Increasing water intake is the most important non-behavioural factor in managing FIC patients. By making the urine more dilute, we can potentially reduce neurogenic inflammation of the bladder - we are aiming for a specific gravity of below 1.035.
Ideally, the patient should be fed a wet diet and other techniques for increasing water intake (e.g. providing drinking fountains, multiple water sources, flavoured water with meat cooking liquids, different types of water bowls) should be used at home.

Urinary acidifying diets are not required in cats with FIC but may be required in other specific causes of FLUTD (e.g. struvite urolithiasis). Cats with calcium oxalate crystals will not benefit from a urine acidifying/dissolution diet, as these stones cannot be dissolved with diet. Some diets (such as c/d or diets with an S/O complex) can be used to minimise the development of crystals in the future.

Rather than focusing on resolving crystalluria, we want to focus on increasing water intake in FIC cats, as crystalluria can be a normal finding in some of these cats.

Encouraging weight loss and activity is also important in managing FLUTD. Maintaining a normal body weight can help minimise the risk of future signs. If a weight loss diet is to be introduced, this should be done so after any episodes of urinary signs have resolved, once the animal has returned to ‘normal’, to prevent food aversion.

Environmental and Behavioural Adjustments

We need to ensure steps are taken to minimise stress both at home and during any visits to the clinic. 

In the clinic, we can make lots of small changes which can really help these patients, including:

  • Minimising the sight, sound and smell of dogs/other species (e.g. examining the cats in a different ward or room, if dogs are in the prep room etc)

  • Avoiding cats seeing other cats in the clinic - e.g. covering part of the kennel, or filling your cat kennels in a way that minimises this

  • Providing similar resources to those used at home (e.g. litter type, tray type, food and water bowls, bedding, etc)

  • Providing a hiding place in the kennel (this can be as simple as a cardboard box with a hole cut in it, or a plastic step-stool covered with a blanket)

  • Using pheromone diffusers e.g. Feliway

  • Gentle handling with minimal restraint and using fear-free principles

  • Using sedation early on in hard-to-handle cats, so we don’t have to resort to forceful handling or restraint tools like cat muzzles or gauntlets

  • Using anxiolytics routinely in the hospital where appropriate

We also want to keep the patient’s hospitalisation as short as possible, depending on the severity of the patient’s signs, and whether they present with a urethral obstruction. Because stress is such a big component in the disease process, we need to minimise stress in these patients. As soon as it is safe for the patient to do so, they should be discharged.

Long Term Care

FLUTD is not a ‘simple fix’ condition and ongoing monitoring, care and at-home adjustments are typically needed. The long-term goals are to minimise recurrence of any episodes, by providing an appropriate environment, minimising stress, and adjusting diet.

The veterinary nurse plays a vital role in supporting the client through this and providing advice. By supporting them throughout the process, we can minimise their feeling overwhelmed by their pet’s condition, improving compliance and reducing the risk of repeat episodes.

Behavioural & Environmental Adjustments

If the cat is part of a multi-cat household and there are signs of conflict between cats in the home, we need to adjust how resources are divided/positioned in the home to minimise this.

Each cat should have 1 set of key resources (food/water bowls, litter tray, resting/hiding place, access to play and human interaction) plus one extra set in the home. These should be positioned carefully to minimise conflict (e.g. one cat guarding a row of litter trays for example). 

Pheromones can also be used to help minimise stress (ideally using feline facial pheromone for all cats, and cat-appeasing pheromone for multi-cat households).

Litter Tray Facilities

Appropriate litter tray facilities should be provided to encourage their use and minimise any stress associated with urination. 

Ideally, a large tray should be used, deeply filled with the cat’s preferred litter type, and positioned in quiet/secluded areas of the home.

Preparing for Stressful Events

If something like a house move, building work or vet visit is coming up, these should be prepared for in advance to minimise their impact on the cat. This may include techniques such as getting the carrier out early ahead of a visit to the vet, letting the cat get used to it before it is used, and spraying it with pheromones to minimise associated stress.

Follow-Up

Most cases of FIC resolve spontaneously within 3-7 days, and recurrence can be avoided in many patients where appropriate changes are made at home. A small number of cases will have chronic or recurrent FIC. In these patients, drug treatment with GAG replacers, and a referral to a behaviourist may be required.

In cats with FIC, episodes are usually short and little in-clinic follow-up care is required unless a repeat episode occurs. If possible, check-ins by the veterinary technician/nurse a few days after discharge should be considered via telephone/email, to ensure the patient is recovering well at home, and to provide any additional advice.

As you can see, there is a lot to think about when caring for cats with FLUTD - both in the hospital and at home! Do you get the opportunity to discuss long-term support with your FLUTD cat clients? DM me on instagram and let me know!

PS. If you want to know more about how to support the FLUTD patient at home, I’ll be discussing it in detail during the upcoming Conquer Your Clinics programme - the one-stop guide to setting up and running successful medical clinics. Pop your name on the waitlist here to be notified once it goes live!

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