Abstract
Practical relevance:
Lower urinary tract signs (LUTS) such as dysuria, haematuria, periuria, pollakiuria and stranguria can occur as the result of a variety of underlying conditions and diagnostic investigation is required to uncover the underlying cause and select appropriate treatment.
Aim:
The '2025 iCatCare consensus guidelines on the diagnosis and management of lower urinary tract diseases in cats' provide an overview of the common presenting signs caused by underlying feline lower urinary tract (LUT) diseases in cats, which often are indistinguishable between different underlying causes. The Guidelines set out a diagnostic approach to affected cats before focusing on the most common causes of LUTS: feline idiopathic cystitis (FIC), urolithiasis, urinary tract infection and urethral obstruction. The aim is to provide practitioners with practical information on these problematic conditions.
Clinical challenges:
The fact that LUTS are similar despite different underlying causes creates a diagnostic challenge. The most common cause of LUTS, FIC, is challenging to manage due to a complex pathogenesis involving organs outside the LUT. Urethral obstruction is a life-threatening complication of various underlying LUT diseases and recurrent LUTS can lead to relinquishment or euthanasia of affected cats.
Evidence base:
These Guidelines have been created by a panel of experts brought together by International Cat Care (iCatCare) Veterinary Society (formerly the International Society of Feline Medicine [ISFM]). Information is based on the available literature, expert opinion and the panel members' experience.
Introduction
Lower urinary tract signs (LUTS) in pet cats (Felis catus) include variable combinations of dysuria, haematuria, periuria, pollakiuria and stranguria (Figure 1), and can result from a range of pathologies. These are common presentations in feline patients, and often chronic and recurrent in nature.1-3 They are caused by various lower urinary tract (LUT) diseases, most frequently idiopathic cystitis. Urethral obstruction (UO), which occurs almost exclusively in male cats, is a manifestation of LUT disease with life-threatening complications. 4 Diagnosis of the cause of LUTS and management of the LUT disease can be challenging for practitioners and frustrating for caregivers, and conflicting results in published studies add to the complexities.
Also, terminology in this area of medicine has changed over the years, which likely contributes to misunderstanding by caregivers and clinicians. 'Feline urologic syndrome' was a term used initially in the 1970s, 5 while 'feline lower urinary tract disease' (FLUTD), introduced in the 1980s, remains widely used as an umbrella term to describe a multitude of conditions causing LUTS.4,6 The acronym 'FLUTD' is not a diagnosis and does not describe the cause of the signs; nor does it assist with caregiver understanding of the complex pathophysiology of many underlying LUT diseases. Unfortunately, use of the term 'FLUTD' may also encourage a diagnostic endpoint, despite the variety of underlying causes.7,8 These Guidelines refer to 'LUT diseases' to encompass the multiple causes of LUTS; 'diseases' is intentionally plural so as not to imply any single diagnosis.
Lower urinary tract signs in cats include dysuria, haematuria, periuria, pollakiuria and stranguria in various combinations, and are caused by a variety of underlying pathologies. Image courtesy of Samantha Taylor
A common cause of LUTS, 'feline idiopathic (interstitial) cystitis', is also inappropriately named.9,10 This condition in cats is generally not associated with a significant inflammatory response, and the term 'interstitial,' which was adopted because of similarity with human interstitial cystitis (bladder pain syndrome), poorly explains the condition and fails to encompass its association with wider pathology of (other) organ, endocrine, and peripheral and central nervous systems (see 'Feline idiopathic cystitis'). 11 Use of the term 'cystitis' in discussion with caregivers may imply a bacterial cause (as is common in people), encouraging the overprescription of antibiotics for what is frequently a sterile condition. Nevertheless, the term 'feline idio-pathic cystitis' is used widely by veterinary professionals and in publications. Hence 'FIC' remains the term used in these Guidelines to describe the idiopathic condition commonly causing LUTS.
For ease of reference, Box 1 provides a glossary of terms used in these Guidelines.
The aim of the '2025 iCatCare consensus guidelines on the diagnosis and management of lower urinary tract diseases in cats' is to provide primary care practitioners with a review of the literature and easy-to-access practical information to assist in the approach to, and management of, these challenging cases.
Presenting signs of lower urinary tract diseases
As mentioned, despite different underlying causes, the presenting signs of LUT diseases in cats are broadly similar and include dysuria,
Young Bengal cat adopting a standing position, with erect quivering tail, typical of urine spraying as a problem behaviour. Image courtesy of Linda Ryan
haematuria, periuria, pollakiuria and stranguria. Periuria (urination outside the litter tray) is a common sign of LUT diseases.18,19 Distinguishing periuria from urine spraying is essential to differentiate medical and behavioural causes (Box 2). Importantly, LUT diseases should be excluded before a behavioural cause is assigned when a cat presents with urination outside the litter tray.
Urinary incontinence is an unusual but important presenting sign of LUT diseases (discussed later). Non-urinary signs may include overgrooming of the abdomen (Figure 3), perineum and hindlimbs, indicating underlying pain, and non-specific signs such as lethargy and hyporexia. Weight loss, polydipsia/ polyuria and gastrointestinal signs may occur in cats with comorbidities such as chronic kidney disease (CKD). Cats with UO may present with mild to severe systemic illness, as well as unproductive stranguria (which caregivers may mistake for straining to defecate).
Causes of lower urinary tract diseases
In various studies that have examined the prevalence of LUT diseases over the past three decades or so, a cause in around 55-65% of cases could not be established, and cats were classified as having FIC.8,18,19,23,24 Conditions causing LUTS (Box 3) may present with or without UO and may be multifactori-al and involve behavioural factors.
Diagnostic approach to cats with lower urinary tract signs
As presenting LUTS often may not differ between the various underlying causes of LUT diseases, a logical approach to investigation is essential, though may be tailored according to the severity of clinical signs, patient history and number of similar episodes that have occurred previously, as well as caregiver finances. Figure 4 describes a summary of the approach to affected cats. Importantly, aetiologies may vary between episodes of LUT diseases, so it should not be assumed that recurrent LUTS always have the same underlying cause. 24
Overgrooming of the abdomen in a cat with idiopathic cystitis. Image courtesy of Samantha Taylor
History-taking
In addition to recording the LUTS and signs referable to other organ systems (inappetence, vomiting, etc) reported by the caregiver, environmental and behavioural aspects may be pertinent, warranting a more thorough history (see 'Environmental and behavioural considerations for management of lower urinary tract diseases', and the questionnaire for caregivers of cats with lower urinary tract signs in the supplementary material). For cats with outdoor access, urination may not be observed, but perineal staining, over-grooming of the abdomen, perineum or hindlimbs, and unusual urination indoors may suggest an LUT disease. The colour and volume of urine passed should be recorded, if known (eg, by assessing the size of the deposit [or 'clump'] where clumping litter is used).
Physical examination
General examination and recording of vital signs should be performed, and body weight and body/muscle condition score assessed. Assessment of hydration is also important, particularly for cats with UO. Physical examination will rarely provide a diagnosis but may guide further investigations. It should include kidney and bladder palpation. The latter may identify a painful, firm, distended bladder, consistent with UO, or a small, thickened bladder with other LUT diseases. Uroliths are rarely palpable. 25 Perineal examination is important and occasionally gritty material can be seen adherent to the prepuce, or there may be evidence of self-trauma.
Laboratory testing
Serum biochemistry and a complete blood count may be indicated. Although rarely providing a diagnosis of LUT disease, comor-bidities may be detected as well as abnormalities that may influence further tests and treatment choices. Triage of cats with suspected UO is discussed later.
Urinalysis
Urinalysis is a vital part of the investigation of all LUT diseases. Results should be assessed in the light of the cat's diet (wet or dry), urine collection method, and sample storage and handling, to avoid any misinterpretation (Box 4). USG (prior to fluid therapy) should be measured with a refractometer. A dipstick assessment and timely (within 1 h) sediment examination should also be performed.29,30 Artefactual crystalluria (struvite or calcium oxalate) can occur if samples are analysed over an hour after collection, or are refrigerated.27,31
Algorithm for the approach to cats with signs of lower urinary tract (LUT) diseases. CKD = chronic kidney disease; DM = diabetes mellitus; DV = dorsoventral; FIC = feline idiopathic cystitis; LUTS = lower urinary tract signs; PU/PD = polyuria/polydipsia; UO = urethral obstruction; USG = urine specific gravity. See relevant sections of the Guidelines for further information on many aspects listed in the algorithm, including emergency treatment of UO
Microscopic appearance of (a) haematuria, (b) struvite crystalluria, (c) calcium oxalate dihydrate crystalluria and (d) a bilirubin crystal. Images courtesy of (a-c) Francesco Cian and (d) lona Mayer (d)
Figure 5 shows the microscopic appearance of haematuria and common urine crystals.
For bacterial culture, urine should preferably be obtained via cystocentesis before any antimicrobial therapy is given, and submitted for quantitative culture and antibiotic sensitivity testing. 17 Manual expression is not recommended as it will cause pain and stress, and potentially damage to the bladder wall. A cat friendly approach to patient interactions -centred on understanding and responding to the current emotional state of the cat - may facilitate conscious cystocentesis (Figure 6). Practical guidance is available in the '2022 AAFP/ISFM cat friendly veterinary interaction guidelines: approach and handing techniques'. 32 Catheter-isation for urine sampling is not generally recommended as it may cause trauma and samples may be contaminated; nor should urine be cultured from urine collection bags. 16
Gentle, cat friendly interactions can facilitate conscious cystocentesis. Image courtesy of Richard Murgatroyd
Imaging
Imaging can be very valuable for the assessment of cats with recurrent or severe LUTS. It is also indicated for diagnosing or excluding urolithiasis and is recommended for cats with signalment, clinical signs or physical examination findings that are atypical for FIC (eg, older cats, or cats with palpable bladder abnormalities or incontinence).
Radiography
Survey abdominal radiographs may be useful for detection of radiodense uroliths (Figure 7) and should include lateral and dorsoventral views that span the abdomen and incorporate the pelvic and penile urethra. An enema may facilitate visualisation. 33 In males, the os penis can be present and should not be mistaken for distal urethral urolithiasis (Figure 8). 34 Contrast radiography (retrograde urethrogra-phy [Box 5] or urethrocystography) is relatively easy to perform, cost-effective and can provide valuable information in cats with LUT disease, particularly those with UO. However, ultrasound examination has generally replaced contrast radiography, when available.
Lateral abdominal radiograph showing radiopaque uroliths in the bladder and urethra of a cat. Image courtesy of Rachel Korman
Lateral radiograph of the caudal abdomen of a cat, with a region of the penis magnified. The faint long tubular thin mineral opacity (arrow) at the level of the penis is consistent with the os penis. Image courtesy of Lumbry Park Veterinary Specialists
A urinary catheter with attached syringe filled with contrast material placed in the distal penis. The catheter can be held in place with forceps; a swab placed between the forceps and prepuce can limit trauma. Image courtesy of Samantha Taylor
Ultrasound
Ultrasound examination of the bladder allows identification of calculi (Figure 11), masses, blood clots, echogenic debris and congenital abnormalities. 35 Examination of the kidneys, ureters and other abdominal organs may additionally be indicated and peritoneal/ retroperitoneal fluid may be identified. Importantly, ultrasound does not allow examination of the intrapelvic or penile urethra, locations where pathology is commonly found in cats both with and without UO. Therefore, abdominal radiography (including the caudal abdomen), plus ideally retrograde urethrography and/or rectal examination, is needed to exclude small stones, for example, in this region. Ideally, both imaging modalities are recommended to fully assess the urinary system.
(a) A normal retrograde study and (b) a retrograde urethrogram revealing a stricture and urolith, in two male cats. Narrowing of the urethra, as indicated by the arrow in image (a), is a normal finding and should not be mistaken for a focal stenosis. In image (b), there is a stricture (white arrow) and a filling defect in a dilated section of the intrapelvic urethra (black arrow), consistent with a urolith. This cat later underwent a perineal urethrostomy and several calcium oxalate uroliths were removed. Images courtesy of (a) Lumbry Park Veterinary Specialists and (b) London Vet Specialists
Ultrasound image showing a cystolith with acoustic shadowing, along with a thickened bladder wall. Image courtesy of Samantha Taylor
For a clinical review on urinary tract ultra-sonography, readers are referred to 'Feline abdominal ultrasonography: what's normal? What's abnormal? Renal pelvis, ureters and urinary bladder' by Griffin. 35
Advanced imaging
CT scans are rarely indicated in cases of LUT disease (Figure 12) but do allow identification of anatomical abnormalities (congenital or acquired). MRI scanning may be required to investigate uncommon neurological causes of LUTS (eg, incontinence or urinary retention).
Sagittal CT image from a 4-year-old cat presenting with incontinence. The green arrow shows a mineral material plug in the penile urethra that was causing a partial obstruction. Image courtesy of Samantha Taylor
Cystourethroscopy
Cystourethroscopy can be performed in female cats to visualise masses, uroliths or glomerulations, and to facilitate their biopsy or removal via minimally invasive tech-niques. 36 However, the small size of feline patients limits availability of this technique.
Feline idiopathic cystitis
FIC is the most common cause of LUTS in cats,4,37 and the condition has similarities to interstitial cystitis in humans (also called bladder pain syndrome, among other terms) 10 with respect to abnormalities seen in the bladder, the presence of comorbid conditions, and the relationship with stress.10,38 FIC should be considered a systemic disorder also involving organs other than the bladder, 12 and affected cats may have overlapping health problems (sickness behaviours, 'Pandora' syndrome). 9 In cats with FIC, the presenting signs can be considered the bladder's response to persistent activation of the central threat response system, which is influenced by genetic, epigenetic and environmental factors. 37 Therefore, investigation and management of cats with FIC should look 'beyond the bladder'. 12
Pathogenesis
FIC results from multiple complex and variable nervous, endocrine and immune abnormalities (Figure 13) that not only affect the cat's bladder but also their behaviour, and other organ (including skin and gastrointestinal tract) function. 4
Schematic diagram of chronic pain associated with feline idiopathic cystitis (FIC). FIC has long been thought to result from some toxins in the urine and/or a urothelial permeability defect, which leads to 'bottom-up' nociceptive input to the brain (solid arrows). 'Top-down' (dotted) arrows show how this activation of the central threat response system affects the bladder, causing signs of FIC. More recent studies have found that environmental threats can also result in signs of FIC via top-down input to the central threat response system. Adapted from Koban et al, 39 courtesy of Tony Buffington
Risk factors
Studies examining potential risk factors for FIC have generally reported consistent findings, with identified risk factors including genetics, early adverse experiences, nervous disposition, indoor environment, increased threat responsiveness, frequent diet change, inactive lifestyle, obesity, use of non-clumping litter, multi-cat home, household instability, and lack of elevated vantage points.40-42 These risk factors suggest that FIC is a condition primarily affecting susceptible cats living in provocative environments, and that effective management must address the cat's environment and lifestyle, as well as their bladder pathology. 4
Diagnosis
Diagnosis of FIC is one of exclusion, taking into consideration the number and type of episodes, severity of clinical signs (including comorbidities) and financial resources of the caregiver. No sensitive, specific and clinically available diagnostic test currently exists to confirm FIC; hence, diagnosis is based on signalment, history, risk factors, exclusion of other causes of LUTS (ideally involving imaging) and response to treatment. 37
Management
In most cases, LUTS will resolve in 2-7 days (with or without treatment), but recurrence is common. Given the multifactorial nature of FIC, individual interventions (nutritional modifications or medications) are unlikely to be effective as sole therapy, but may be helpful as part of a multimodal approach. Appropriate multimodal environmental modification (MEMO) has been shown to be effective in reducing the recurrence of all disease signs in cats with FIC and is now the standard of practice in veterinary medicine for management of this condition.13,37 MEMO is the institution of changes to the cat's environment to attempt to reduce LUTS by decreasing the likelihood of activation of the central threat response system. This approach incorporates caregiver education, and variable combinations of changes to the cat's inanimate physical environment, as well as their diet and their interactions with other cats, other animals and humans in their environment. Clinicians should remember that FIC is a painful condition and analgesia should be prioritised.
Pharmacological interventions
Various medications have been used to manage FIC but few have been robustly studied or compared with MEMO in terms of efficacy. The stress of orally medicating cats should be considered when prescribing and may also complicate assessment of the response.
Prednisolone, 43 pentosan polysulfate sodi-um44,45 and glycosaminoglycans46,47 have no significant benefit in cats with FIC, although improvements have been seen in both placebo and treatment groups, possibly related to giving medication in treats (hence reducing the perception of threat and encouraging engaging emotions).48,49 Analgesics such as non-steroidal anti-inflammatory drugs (NSAIDs; meloxicam, robenacoxib), opioids (transmucosal buprenorphine), gabapentin, pregabalin or novel anti-nerve growth factor monoclonal antibodies such as frunevetmab have to date not been studied in non-obstructive FIC. Analgesia is strongly recommended as this is a painful condition. Amitriptyline may be considered in refractory cases, 50 and fluoxetine has been shown to decrease urine spraying. 51 Urinary retention has been reported with fluoxetine. 52
Although FIC is not a urine-marking condition, behaviour medications may be beneficial in other ways (eg, helping a cat cope with environmental stressors or frustration). Furthermore, a cat who is at risk of losing their home or life due to LUTS and litter tray avoidance should be considered a candidate for behavioural medication when there are indications of anxiety and environmental stressors. Importantly, any use of medications for behavioural modification should ideally be discussed with a board-certified or equivalent veterinary behaviourist and used in parallel with environmental modifications. 53 See 'Scent and pheromones' for a discussion of the potential utility of pheromone therapy for FIC.
Nutritional modifications
Nutritional inventions are unlikely to be effective alone, but may be beneficial as part of the multimodal approach. Studies on nutritional interventions have generally included only small numbers of cats; moreover, dietary changes may in themselves be associated with stress because of the particularly sensitive nature of affected cats. Despite this, a survey of veterinarians in the USA showed that urinary prescription diets were the top choice of treatment for non-obstructive FIC. 54
Acidification of the urine or feeding diets to reduce struvite crystals is generally not indicated for non-obstructive FIC, 55 although feeding a wet diet and increasing water intake may help to prevent recurrence,4,13,46 albeit studies are not conclusive. The benefit of adding ingredients to urinary diets to reduce stress (eg, alpha-casozepine, L-tryptophan) has been studied in small numbers of cats with FIC, with significantly fewer cats suffering a recurrent episode in one non-randomised short-term study. 56 In another study, the feeding of a urinary prescription diet reduced the recurrence of some LUTS. 57 However, evidence about the effects of supplementation of these nutrients on long-term FIC management and recurrence is not avail-able. 58 As obesity is a risk factor for FIC, therapy for weight control may be indicated as a long-term goal.
Given the susceptibility of cats with FIC to stress, asking the caregiver what (regulatory-approved) diet their cat prefers, and then suggesting they buy a few different brands to offer the cat to assess their preferences and give choice, may help to reduce activation of the central threat response system.
Radiotherapy
Low-dose radiotherapy is under trial for the management of refractory FIC (go.jfms.com/ NCSU_FIC), with publications awaited. 59
Urolithiasis
Urolithiasis is an important cause of LUTS in cats, accounting for 10-23% of cases.8,60 It is also an important cause of UO.18,61 Clinical signs of urolithiasis will vary according to the location and nature of the stone(s), with cys-toliths sometimes presenting as an incidental finding and in other cases resulting in haema-turia and dysuria. The most common types of urolith are calcium oxalate and struvite (magnesium ammonium phosphate) and these are typically sterile. Together, calcium oxalate and struvite make up around 90% of feline uroliths. 62 Their relative proportions have changed over time, likely driven by dietary trends, with recent studies suggesting that struvite is now more common than calcium oxalate. 60
Other, less common urolith types include urate, cystine, calcium phosphate (apatite), compound and mixed.60,63 Solidified blood uroliths have been occasionally reported, usually found in the bladder and urethra.64,65 In a recent case report, uroliths composed of the antiviral nucleoside analogue GS-441524, used to treat feline infectious peritonitis, were documented in two cats. 66
Risk factors, laboratory and imaging findings, and management approaches for the most common uroliths are summarised in Table 1. Further information on the management of uroliths is available on the Minnesota Urolith Center website (go.jfms.com/ UMN_uroliths) and in the 'ACVIM small animal consensus recommendations on the treatment and prevention of uroliths in dogs and cats'. 73
Characteristics and management of common feline uroliths
USG = urine specific gravity
Investigation
Clinical signs of urolithiasis may be indistinguishable from other causes of LUT diseases and, therefore, the investigations described above (see 'Diagnostic approach to cats with lower urinary tract signs') are warranted.
If uroliths are identified, it is appropriate to consider a complete blood count and biochemistry to look for factors contributing to their formation, such as hypercalcaemia (diagnosed in around 35% of cats with calcium oxalate uroliths),74,75 liver disease such as a portosystemic shunt (urate) or conditions associated with urinary tract infection (UTI) including CKD, hyperthyroidism or diabetes mellitus (struvite). Urinalysis is also indicated
in the investigation of urolithiasis, with measurement of USG and pH as well as sediment examination. There are pitfalls to be avoided in the interpretation of results; for example, urolith type does not consistently match crystal type and uroliths can occur without crystalluria. Urine pH can be altered by the stress of coming to the clinic, delays in analysis, diet and timing of feeding. 29 Radiographic imaging should be considered and all uroliths analysed if removed (Figure 14).
Calcium oxalate cystoliths removed from a Ragdoll via cystotomy. Image courtesy of Samantha Taylor
Management
Management will depend on the location, suspected composition, size and number of uroliths (Table 1), as well as caregiver and cat factors. Options include medical dissolution, surgical removal via cystotomy, voiding uro-hydropropulsion or advanced techniques such as cystolithotomy, lithotripsy, cystoscopy or basket removal.
Urinary tract infections and subclinical bacteriuria
UTI is uncommon as a cause of LUTS in otherwise healthy adult cats (<3%), 18 but the prevalence is higher in certain groups, such as cats with CKD 76 and those over 10 years of age,17,19 where infection should be considered a potential underlying cause. The finding of bacteria in the urine of cats may or may not be associated with clinical signs (Figure 15). 'Subclinical bacteriuria' (see 'Definitions') increases in prevalence with age and the existence of comorbidities, with one study documenting a prevalence of 6.1% in cats over 6 years old. 77
Distinguishing subclinical bacteriuria from UTI can be challenging in a species with private elimination habits and often unsuper-vised outdoor access, and caregivers may underestimate the frequency of urination. 78 This underlines the importance both of caregiver education (see 'Caregiver role and communication') and further diagnostic testing when urine culture is positive. Overprescription of antimicrobials for cats with LUTS remains a concern in the context of antibiotic stewardship.79-81
Bacteriuria can be identified on sediment examination but treatment should take into account the presence or absence of clinical signs. Image courtesy of Francesco Cian
The vast majority of UTIs in cats involve a single bacterial species, most frequently a member of the host's own urogenital or faecal microflora (Escherichia coli, Streptococcus species, Enterococcus faecalis, Staphylococcus felis). 82 Polymicrobial infections tend to be diagnosed more frequently in cats with indwelling urinary catheters or other comorbidities. 17 E faecalis is more likely to be present in cats with subclinical bacteriuria or as part of a polymicrobial infection. 83 Corynebacterium urealyticum is a rare cause of UTI but more common in cats undergoing urethral catheterisation or urological surgery. 84
Fungal UTIs (eg, Candida species, Cryptococcus species) are documented; comorbidities (eg, diabetes mellitus or CKD), therapies causing immunosuppression (eg, corticosteroids) or a history of recent antibacterial drug therapy are common factors in affected cats.85,86 Viral infections such as calicivirus, 87 herpesvirus 88 and coronavirus 89 have been suggested as a cause of LUTS,90,91 but associations have not been consistently demonstrated. 89
Risk factors
Signalment and both local and systemic factors can predispose cats to the development of UTI and subclinical bacteriuria, with female sex and increasing age being consistently reported (Box 6).92-96 CKD, diabetes mellitus and hyperthyroidism are the most frequently documented systemic comorbidities. 95 Despite an increased prevalence in cats with CKD, bacteriuria (subclinical or UTI) does not seem to affect disease progression or survival. 97 UTI may, however, contribute to decreased insulin sensitivity in cats with diabetes. 98 Urethral catheterisation and perineal urethrostomy increase the risk of UTI (see 'Urethral obstruction' for a discussion of antibiotic use in UO), but prophylactic antibiosis is not recommended. 16
Management
Antimicrobial treatment of subclinical bacteri-uria is generally not recommended, 16 nor is culture of a multidrug-resistant bacterial species, in itself, an indication to treat (or suggestive of enhanced pathogenicity). Treatment of subclinical bacteriuria may be considered in cats with diabetes mellitus (if bacteriuria is thought to contribute to poor diabetic control) or suspected pyelonephritis, or who are undergoing urinary tract surgery or endoscopy.16,17
For cats with clinical signs of UTI, treatment should be based on bacterial culture and sensitivity testing, and analgesics should also be provided (eg, an NSAID, if there are no contraindications, or an opioid). Enterococcus species are intrinsically resistant to beta-lactams, cephalosporins, trimethoprim sulfon-amide and fluoroquinolones. 99 If treatment is needed while results are pending, a first-line antimicrobial such as amoxicillin or trimetho-prim sulfonamide (although the latter can be be difficult to administer to cats) should be selected. 16 A treatment duration of 3–5 days may be adequate for 'simple' UTIs (ie, an otherwise healthy individual), but these are uncommon in cats. Lack of response should prompt further investigation and empirical changes of antibiotic should be avoided. Cats will more commonly have 'complicated' UTIs (ie, comorbidities present), and treatment should be based on culture and sensitivity results, with a recommended duration of treatment of 3–5 days for a first infection or reinfection, and 7–14 days for persistent or relapsing infection. 16 Longer courses may be needed for pyelonephritis. 16
Third- and fourth-generation cephalosporins (eg, cefovecin) are prescribed for cats with LUTS;80,81 however, along with fluoro-quinolones, these antibiotics should be reserved for cases with clinical signs of UTI, pyelonephritis or bacterial isolates resistant to lower-tier antibiotics. Long-acting cefovecin injections should not be used empirically without urine culture,16,17 and critically important human antibiotics (eg, carbapenems) should not be used to treat feline patients.
Alternative approaches to the management of recurrent UTIs are poorly studied in cats. In humans, and anecdotally in animals, pro-biotics, cranberry extract, D-mannose, bacterio-phage (phage) therapy 100 and inoculation with less pathogenic bacteria have been investigat-ed. 101 Frequent voiding (supported by analgesia for degenerative joint disease in older cats), stress reduction and increased water intake will benefit cats with UTIs, and can be encouraged by appropriate environmental modifications/enrichment (see 'Environmental and behavioural considerations for management of lower urinary tract diseases').
Urethral obstruction
UO is a potentially life-threatening consequence of any type of LUT disease. FIC is the most commonly reported cause of obstruc-tion,4,102 but urolithiasis should be considered and excluded. Urethral plugs (comprising combinations of proteinaceous material, inflammatory cells and crystals) can occur as sequelae of underlying LUT diseases such as FIC and less commonly UTI or urolithiasis (or a combination). Other causes of UO include anatomical abnormalities (strictures, spasm, congenital defects) and occasionally neoplasia.103,104
Pathophysiology
Complete UO results in increased intravesi-cular pressure, leading to bladder wall pressure necrosis and mucosal injury. The increased hydrostatic pressure from obstruction downstream may be transmitted to the ureters and kidneys; and, when renal pressure exceeds glomerular filtration pressure, renal blood flow and glomerular filtration rate decrease. Tubular concentrating ability is subsequently affected, leading to impaired sodium and water reabsorption, with impaired excretion of phosphorus, potassium, blood urea nitrogen, creatinine and hydrogenions.104-106
Severe metabolic derangements, such as hyperkalaemia, metabolic acidosis and hypo-calcaemia, can develop. Hyperkalaemia is the most common life-threatening complication and can lead to bradycardia and cardiac arrhythmias (exacerbated by hypocalcaemia). Uraemia is seen within 24-48 h when UO is complete and acute. Ongoing gastrointestinal losses and decreased fluid intake (vomiting, anorexia) can lead to marked dehydration, azotaemia and hypovolaemia.
If left untreated, complete UO can result in severe bradycardia, bladder rupture, uroab-domen, concurrent shock and death.106,107
Triage
Cats presenting with LUTS should be triaged rapidly (Box 7) to determine if they have UO and life-threatening consequences such as shock (bradycardia, hypothermia, hypotension) and hyperkalaemia. Figure 16 presents an algorithm to assist decision-making and initial management for feline UO.
Diagnosis
Algorithm for the approach to cats with suspected urethral obstruction. CBC = complete blood count; FIC = feline idiopathic cystitis; GA = general anaesthesia; LUTS = lower urinary tract signs; MEMO = multimodal environmental modification; PCV = packed cell volume; POCUS = point-of-care ultrasound; TS = total solids; UTI = urinary tract infection
mmol/l). 109
Management
Fluid therapy
Intravenous (IV) fluids are needed to address dehydration and hypovolaemia, restore renal perfusion and correct hyperkalaemia. Initiation of fluid therapy should not be delayed until a urinary catheter is placed as fluid therapy will help to restore renal perfusion and reduce serum potassium. Crystalloid fluid choices include 0.9% saline or balanced isotonic fluids containing 4-5 mmol/l potassium. Evidence suggests that balanced isotonic crystalloids may be preferable as they correct acidosis more rapidly, although fluid type (0.9% saline or balanced isotonic fluids) was shown to have no influence on normalisation of serum potassi-um.113,114 Cats must be closely monitored with point-of-care ultrasound (POCUS; Box 8) for evidence of volume overload. Risk factors for fluid overload include administration of fluid boluses or the development of a heart murmur/ gallop rhythm. 120 Volume overload during therapy for UO is associated with increased costs and a longer duration of hospitalisation (4.1 vs 1.8 days in one study 120 ). Postobstructive diuresis (see later) is a common complication of UO. 121
Ultrasound images demonstrating findings and changes relating to the caudal vena cava (CVC) in cats with differing volume status. (a,b) Hypovolaemic cats will have a flat/collapsed CVC (white arrows) that may or may not change between (a) expiration and (b) inspiration, depending on the severity of hypovolaemia. In this example the CVC does change significantly between expiration and inspiration. (c,d) Hypervolaemic cats will have a distended CVC (white arrows) that changes very little between (c) expiration and (d) inspiration. (e,f) Cats who are euvolaemic should have at least a 20% change in the diameter of the CVC between (e) expiration and (f) inspiration. In this example the change is around 40%. Images courtesy of Soren Boysen
Where bolus fluid therapy is necessary (eg, in patients presenting in shock), a goal-oriented approach should be followed; for example, administration of a tailored 10 ml/kg IV isotonic crystalloid bolus over 10 mins, with reassessment of mentation, heart rate, pulse quality, mucous membrane colour, capillary refill time, blood pressure and POCUS findings until endpoints of resuscitation are achieved. Note that previously described high 'shock rates' of fluids are no longer recommended owing to the risk of fluid overload. 122
Decompressive cystocentesis
Decompressive cystocentesis is controversial. Box 9 summarises pros and cons of the technique and provides some brief practical guidance for reducing risks.
Management of hyperkalaemia
IV fluid therapy is the fastest way to decrease potassium concentrations, and should be initiated prior to unblocking the cat.125,126 Figure 18 summarises the clinical approach and Table 2 includes dosages for adjunctive medications.
Algorithm for the management of hyperkalaemia in cats with urethral obstruction. The inset box shows changes on an electrocardiogram (ECG) that are typical in cases of feline hyperkalaemia, including decreased to absent P waves, widened QRS complexes, shortened QT intervals and tall tented or enlarged reversed T waves. IM = intramuscularly; IV = intravenously. ECG image courtesy of Samantha Taylor
Management of hyperkalaemia in cats with urethral obstruction (in addition to intravenous fluid therapy*)
Intravenous fluids (see text) are the mainstay therapy for management of hyperkalaemia
CNS = central nervous system; CRI = continuous rate infusion; IV = intravenously; IM = intramuscularly
Calcium gluconate is the first-line medication to treat life-threatening hyperkalaemia with bradycardia. The rationale is that ionised hypocalcaemia is present in 75% of cats with UO and exacerbates the effects of hyper-kalaemia. Increased severity of hypocalcaemia is correlated with more severe cardiovascular compromise and a poorer prognosis. 128 Calcium gluconate may stabilise patients long enough to relieve UO and/or allow other potassium-lowering therapies to take effect. During administration of calcium gluconate, the patient should be monitored for arrhythmias (ECG or heart auscultation). In the absence of ECG monitoring, therapy is generally indicated when the heart rate is below 160 bpm.
Analgesia
The provision of analgesia is a priority. UO is a painful condition and, moreover, management of pain can reduce urethral spasm in some cats, resulting in spontaneous urina-tion. 125 Use of a pure opioid will allow titration of the dosage to provide effective analgesia. Suitable options include metha-done 0.2 mg/kg IV, a continuous rate infusion of fentanyl (3-20 μg/kg/h IV) or a fentanyl patch (taking into account delayed onset and variable efficacy). 129 Buprenorphine (0.02-0.04 mg/kg IV) could be used for less severe cases and for ongoing analgesia after catheterisa-tion. The addition of meloxicam has not been shown to have any benefit in cats with UO, 130 and is generally not recommended in the initial management period. However, NSAIDs may be useful postobstruction if no contraindications remain present (eg, azo-taemia or fluid deficits). 131
A sacrococcygeal epidural (caudal epidural or coccygeal block; Box 10) with bupivacaine, lidocaine or a bupivacaine/morphine combination provides local analgesia to the perineum, tail, penis, urethra and anus. The technique can also reduce propofol requirements and has been shown to extend the time to rescue analgesia.132,133
Further details on analgesia can be found in the '2022 ISFM consensus guidelines on the management of acute pain in cats'. 129
Sedation and anaesthesia for catheter placement
The choice of sedation vs general anaesthesia will be dictated by the patient's clinical status. Collapsed cats, for example, may be adequately sedated with a combination of an opioid (eg, methadone 0.2 mg/kg IV or IM) and midazolam (0.25 mg/kg IV or IM). Alternative combinations such as butor-phanol 0.2 mg/kg IV and diazepam 0.2 mg/kg IV can be considered, being mindful that butorphanol will not provide adequate analgesia as a sole agent. 129 Ketamine (10 mg/kg IV) and diazepam (0.5 mg/kg IV) can also be titrated to effect, as needed.103,125,134
Sacrococcygeal epidural administration of local anaesthetics can provide an adequate means of pain management in cats with urethral obstruction. Leakage of spinal fluid is less likely at this location but can occur, as shown in this image. Image courtesy of Paulo Steagall
However, most cats with UO will require general anaesthesia to ensure relaxation of the urethra and avoidance of pain and stress, although one recent study documented no difference between sedation and anaesthesia in terms of success of catheterisation or recurrence of UO. 134 Bradycardia, hypotension and hypovolaemia should be corrected prior to general anaesthesia. Further details on anaesthetic agents can be found in the 'AAFP feline anesthesia guidelines'. 135
Antispasmodic therapy
Studies on the use of antispasmodic therapy to relax smooth and skeletal muscle in the urethra of cats with UO have produced conflicting results. Both phenoxybenzamine (2.5-7.5 mg/cat PO q8-12h) and prazosin (0.25-0.5 mg/cat PO q24h) are alpha-1 antagonists that induce smooth muscle relaxation. Prazosin was not shown to reduce the recurrence of UO in more recent studies,136-138 despite earlier work suggesting efficacy 139 and benefit over phenoxybenzamine, 140 with the latter medication taking up to a week to become effective. Based on current evidence, administration of prazosin is not generally recommended. However, further work is needed to see if subsets of cats with UO may benefit, as studies varied with respect to dosage and duration of therapy, and lack of weaning before drug withdrawal may have resulted in rebound spasm. If used, initiation of alpha-1 antagonists should be postponed until fluid deficits and azotaemia are corrected, as hypotension is a potential adverse effect.
Similarly, there is little evidence for the efficacy of acepromazine as a urethral muscle relaxant, and the resulting hypotension could reduce renal blood flow.
Skeletal muscle relaxants have been poorly studied in the management of UO. Dantrolene resulted in intraurethral muscle relaxation in a study measuring intraurethral pressure, 139 but can be challenging to dose orally due to patient size. Oral diazepam is associated with idiosyncratic hepatic necrosis and, hence, is not recommended. The benefit of IV diazepam as a skeletal muscle relaxant has not been studied but its usage could be considered as part of a multimodal anaesthesia regimen when catheterising cats with UO. Alprazolam has not been studied.
Urinary catheter selection
Gentle massage of the tip of the penis to remove urethral plugs and distal uroliths. Image courtesy of Rachel Korman
(a-d) Photographs and accompanying diagrams to illustrate the importance of moving the penis (and thus urethra) dorsally and caudally to straighten the naturally occurring 'S' bend in the urethra (a,b) and allow passage of the catheter (c,d). This is performed by gently moving the prepuce (arrow). Images courtesy of Soren Boysen
A lubricated tomcat catheter with attached syringe of saline is inserted into the cleansed urethral orifice of an obstructed cat. Using pulsatile flushes, the catheter is slowly advanced. Image courtesy of Rachel Korman
(a; top to bottom) Polypropylene catheter, polypropylene catheter with adjustable suture wings, Jackson cat catheter with stylet, polytetrafluoroethylene catheter, and (insert) polytetrafluoroethylene catheter used both for unblocking and as an indwelling catheter. (b) Polyvinyl catheter. (c) Olive tip catheters. Images courtesy of (a) Danielle Gunn-Moore and (b,c) Serge Chalhoub
An intravenous catheter (with stylet removed) can be useful for flushing the distal urethra. Image courtesy of Rachel Korman
Maintenance of the urine collection system
Closed urine collection systems should be used, to prevent ascending iatrogenic infection and allow measurement of urine output. Commercially available sterile collection bags and connecting lines are preferred, but empty (ideally sterilised) IV (non-dextrose) fluid bags can be a cost-effective alternative. Urine collection systems should be changed every 2 days to avoid the risk of nosocomial infection and handled with gloves (sterile if also handling the catheter). The collection bag should be positioned below the level of the bladder to allow gravitational drainage, but kept off the floor for hygiene reasons (Figure 29). The entire collection line and the junction
(a) A red rubber catheter that has been advanced into the urinary bladder. Two stay sutures have been placed, one on each side of the perineum ('earring method'), and butterfly tape has been used to fix the catheter to the stay sutures. Two simple interrupted sutures secure the tape to the stay sutures. (b) An alternative method for securing a urinary catheter. In this case a 'Slippery Sam'-type catheter is secured with sutures to the prepuce and connected to a closed urine collection set using a 'Little Herbert' Luer lock connector. See text for discussion regarding choice of indwelling catheter. Images courtesy of (a) Serge Chalhoub and (b) Rachel Korman between the catheter and prepuce (or vagina) should be wiped with 0.05% chlorhexidine every 8 h or whenever contamination is seen. The following should be monitored:
Finger trap suture on a red rubber urinary catheter. The suture was started at the butterfly tape end, and continued downwards along the catheter for about 1-2 cm. Image courtesy Chantal McMillan
Urinary catheters (red rubber [a] and Mila [b]), each attached to a closed urinary collection system, have been secured to the cat's tail to avoid tension on the prepuce.
An indwelling catheter connected to the collection tubing with a swivel device, allowing the tubing to twist and avoid traction on the prepuce. Image courtesy of Rachel Korman
✜ Urine production Empty the bag every 4 h and calculate urine volume produced (ml/kg/h). Comparison of fluid given ('ins') and urine produced ('outs') will ensure that the IV fluid rate is adequate and that the urinary catheter is patent;
✜ USG Measure every 4 hto ensure urine is dilute and the IV fluid rate adequate.
Hospitalisation of the obstructed cat
Cats with LUT disease and UO are painful and likely to be anxious. A cat friendly veterinary environment is vital to reduce stress and optimise recovery, and should incorporate: a cat-only ward (if not available, cats could be hospitalised in a cage in another room away from dogs); opportunities to hide, both within the examination room and within the hospital cage (hiding is a critical coping mechanism); and means of encouraging engaging emotions. An Elizabethan collar may be required to prevent patient interference with the urinary catheter but can result in stress and challenges accessing litter trays and hiding places. Large apertures to beds and supervised time without the collar is recommended. A fabric collar may suffice for some patients.
Further advice and discussion of cat friendly principles is provided within the '2022 ISFM/AAFP cat friendly veterinary environment guidelines' 146 and the 'Environmental modifications' section later. Importantly, cats may have litter substrate and litter tray preferences,147,148 which are ideally replicated in the hospital; this may involve trialling soil or sand to imitate outdoor substrates.
(a) A sterilised intravenous drip bag is used as an economic closed collection system. Note it is not in direct contact with the floor and disinfectant is available to wipe connections clean when emptying or disconnecting the system. The cage front is covered with a towel to offer the cat a hiding opportunity. (b) A commercially available urine collection bag that allows easy measurement of urine output and is likewise kept off the floor. Images courtesy of (a) Rachel Korman and (b) Lumbry Park Veterinary Specialists
Other considerations for the hospitalised cat are outlined below.
Medical management without catheterisation
A technique for management of UO without catheterisation has been described for cats with suspected urethral spasm (minimal biochemical derangements and normal abdominal radiographs). 154 The protocol involved: sedation with acepromazine (0.25 mg/cat IM or 2.5 mg/cat PO q8h) and buprenorphine (0.075 mg/cat IM q8h), with medetomidine given after 24 h (0.1 mg/cat IM q24h); massage to dislodge any obstructions in the distal penis; subcutaneous fluids; decompressivecystocentesis; and use of a low-stress (darkened, low-traffic) environment. Spon - taneous urination occurred in under 72 h in over 70% of cases. it is important to note that while this protocol is cost-effective, it would be unsuccessful in the face of ongoing physical obstruction (eg, urolithiasis), which cannot be ruled out without catheterisation and possibly retrograde urethrography.
Considerations if catheterisation is not achieved
In some cats with UO, placement of a urinary catheter is challenging or occasionally impossible. Potential causes and recommendations are listed in Table 3. Note that cystostomy tube placement may be successful for urinary diversion (Figure 30), but is associated with a relatively high (49%) rate of complications. 158 Distal obstructions may be managed with perineal urethrostomy, with a retrospective case series indicating a good prognosis, 159 although the risk of UTI is increased. 160 The procedure can be considered in recurrent cases (eg, with caregiver cost limitations) but, importantly, underlying disease such as FIC should still be addressed, as described, to manage ongoing bladder pathology.
A cystostomy tube placed in a cat with a proximal urethral rupture to provide urinary diversion. Image courtesy of Helen Kirkpatrick
Failure to pass a catheter in cats with urethral obstruction: causes and recommendations
For more information, readers are referred to 'Urinary tract trauma in cats: stabilisation, diagnosis and management', by Robakiewicz and Halfacree 157
In the event a catheter cannot be placed despite addressing potential causes, decom-pressive cystocentesis may be performed and advice sought from a specialist centre.
Appropriate use of antibiotics for cats with urethral obstruction
As discussed earlier (see 'Urinary tract infections and subclinical bacteriuria'), prophylactic antibiotic treatment of cats with indwelling urinary catheters is not recommended, 16 and culture of urine from the catheter or collection bag, or of the catheter itself when removed, may identify bacteriuria rather than a UTI. 161 Ideally, samples are obtained via cystocente-sis if infection is suspected, taking into consideration that the bladder wall may be more friable given the recent UO.
Acquired bacteriuria in cats treated for UO with catheterisation was uncommon (13%) in one study, 162 and aseptic practices in placement and management of urinary catheters may minimise the risk of ascending infection. Catheters should not be left to drain 'open' without a collection system due to the high risk of infection. Catheters are usually in place for no longer than 24-36 h (unless the patient is azotaemic - see 'Indwelling catheter vs outpatient management'), which also reduces the risk of catheter-acquired infections. Clinical monitoring for signs of UTI (pyrexia, gross or cytological haematuria and pyuria) is recommended in catheterised patients, with removal of the catheter and quantitative culture of a cystocentesis sample performed if UTI is suspected. 16 Similarly, culture is recommended for cats with ongoing clinical signs after catheter removal. 17
Complications
Complications of UO include bladder damage (with possible uroabdomen), iatrogenic urethral damage and tears, urethral stricture (usually within 3 months of a traumatic urethral catheterisation), 163 acute kidney injury, iatrogenic UTI, persistent LUTS, post-obstructive diuresis, hypokalaemia, dehydration and hypoperfusion. Trivial to small amounts of free abdominal fluid can be identified in cats with UO without evidence of urethral or bladder tears; however, only retrograde contrast studies can exclude these possible complications. 124
Detrusor atony (overdistension of the bladder causing damage to tight junctions) is uncommon but can result in failure to urinate and retention of residual urine after voiding despite patency of the urethra. 164 Signs include severe overdistension of the bladder during UO, a flaccid bladder on palpation once obstruction is relieved, residual urine and urine leakage. 165 Return of normal detrusor function can be achieved by preventing detru-sor stretch to allow re-establishment of tight junctions. This involves keeping the bladder small during the days immediately following relief of UO with an indwelling urinary catheter, and may take 7 days or longer. 166 Other causes of urinary retention (pain, ure-thral spasm, UTI) should be excluded. Bethanechol (1.25-5 mg/cat PO q12h) is a parasympathomimetic that may be used to augment detrusor contraction (only in cats with a patent urethra) and can be given with an alpha-1 antagonist.
If a cat fails to urinate after a urinary catheter is removed, recurrent obstruction is possible, but detrusor atony should be excluded and the stress of hospitalisation (unfamiliar environment, litter preference not addressed, cat usually urinates outside, etc) considered. For some cats, discharge into the home environment is preferable and normal urination will not be observed during hospitalisation.
Discharge post-urethral obstruction management
Ideally, cats are observed to urinate normally before discharge. However, there may be behavioural as well as medical reasons for failure to urinate (see above). At discharge, consideration should be given to how to provide ongoing analgesia for cats in a fashion that produces adequate pain relief, is easy for the caregiver to administer and has the least impact on interactions with the cat (eg, sublingual buprenorphine, oral NSAIDs and/or a fentanyl patch). Additionally, given the influence of stress on LUT diseases, caregivers should be advised on how to reintroduce the previously hospitalised cat to resident cats/ pets to avoid frustration and redirected aggression. Examples include: initially confining the returning cat to one room and using a sock or glove to rub onto the cats' faces to allow mingling of scents; encouraging positive emotions; and allowing the level of arousal of all parties to reduce before reintroduction. 167 See 'Environmental and behavioural considerations for management of lower urinary tract diseases' for further recommendations on post-discharge management.
Prognosis
Reported survival rates to discharge for cats with UO managed using traditional protocols (indwelling catheter) are excellent (91-94%).103,106,125 However, the long-term survival rate varies, with the same studies documenting rates of UO recurrence of 11-58% at various time points, leading to 21% of cats eventually being euthanased. Optimal post-discharge management and caregiver communication may improve such long-term outcomes.
Other lower urinary tract diseases
While FIC is the most common cause of LUTS, and urolithiasis another important cause, other conditions are reported, and it should not be assumed that repeat episodes have the same cause. 42 For example, a cat suffering episodes of FIC as a young adult could have urolithiasis or neoplasia when presenting with haematuria as a senior cat. In a study of bladder neoplasia in 118 cats, 78% had been evaluated previously for LUTS. 168 While the focus of this discussion is LUT pathology, upper urinary tract disease such as renal neoplasia, cysts, trauma and idio-pathic renal haemorrhage can also result in haematuria.
Lower urinary tract neoplasia
Tumours anywhere in the urinary tract can result in clinical signs of haematuria, stran-guria and dysuria, with the bladder being the most frequently affected location. Other clinical signs of LUT neoplasia may include lethargy, abdominal pain and vomiting. 168 Overall, tumours of the bladder are rare in cats, 169 with the most common being invasive UC (previously termed transitional cell carcinoma). Mesenchymal tumours, lymphoma and other tumours are less frequently diagnosed, either as primary neoplasms or as part of a multicentric disease process.170-172 In contrast to dogs, where the trigone is most often affected, UCs tend to be found in more variable locations in cats (Figure 31), and urethral and ureter involvement is possible; the median age of affected cats in one study of 118 cases was 15 years. 168 A history of chronic FIC was reported in 3/11 cats with UC in one study. 173 Diagnosis can be made with imaging, urinalysis, fine-needle aspiration (noting there is a risk of tumour seeding), traumatic catheterisation, and cystoscopic, endoscopic or surgical biopsy.
Ultrasound image of a cat's bladder, showing a mass that was later confirmed to be an invasive urothelial carcinoma.
Treatment of bladder UC in cats may include partial cystectomy, chemotherapy and/or radiotherapy.168,174 In one study, 168 NSAID treatment with or without cystectomy was significantly associated with a longer survival time in cats with LUT UC; in another study, treatment with meloxicam alone was associated with a 1-year survival of 50% in 11 cats. 173 Median survival times with a variety of modalities are approximately 5-12 months.168,172
Urethral neoplasia is even less common and, as suggested, may develop as an extension of bladder neoplasia. It can be treated surgically; palliative stenting is also report-ed. 175 Prostatic neoplasia is also very rare in cats. Surgical treatment is likely the therapy of choice in most cases. 172
Lower urinary tract trauma
Trauma to the urinary tract may occur as a result of external injury, principally from road traffic accidents, but can also be iatrogenic, associated with urinary catheter placement. 157 Signs can include haematuria and stranguria, and other injuries may also be present. The ability to palpate a urinary bladder does not rule out urinary tract trauma. 176 Also, abdominal effusions may not be obvious with intrapelvic urethral rupture as urine will accumulate subcutaneously. 177 Typical serum biochemical abnormalities include azotaemia and hyperkalaemia, and analysis of abdominal effusion (if present) may reveal an abdominal fluid to peripheral blood creati-nine ratio ^2:1, which is predictive of uro-abdomen. 178 Further diagnostic imaging, such as retrograde urethrocystography or contrast CT, may reveal the urinary rupture. For further discussion, readers are referred to 'Urinary tract trauma in cats: stabilisation, diagnosis and management' by Robakiewicz and Halfacree. 157
Congenital lower urinary tract diseases
Congenital defects of the urinary tract are rare in cats, but can occur in all locations of the urinary system. Usually, they manifest at a young age, with LUTS and incontinence (Box 11). Such defects include abnormalities of the bladder (agenesis, hypoplasia, hernia-tion), 181 urethra (ectopic ureters, aplasia, hypoplasia, duplication, prolapse),181,182 ura -chus183,184 and genitalia (fistulas, hypospa-dias). 185 Contrast radiography and advanced imaging may be useful for diagnosis, with treatment and prognosis depending on the specific abnormality. 181
Intravenous urography revealing ectopic ureters in a cat with incontinence. Image courtesy of Rachel Korman
Other causes of lower urinary tract signs
Malakoplakia is a rare chronic inflammatory condition and is reported occasionally in cats.186,187 LUTS are observed together with plaque or mass-like lesions in the urogenital tract that may be mistaken for neoplasia as the masses are composed of large round cells with granular cytoplasm. E coli infection may be involved in the pathogenesis and treatment with antibiotics can resolve lesions.
Environmental and behavioural considerations for management of lower urinary tract diseases
FIC is a threat-responsive disorder and MEMO has been shown to reduce its recurrence by lessening the cat's perception of threat and increasing their sense of control. 13 Moreover, other LUT diseases are also likely to benefit from efforts to address a cat's environmental needs by improving access to resources and reducing stress and anxiety. 188 For example, encouraging water intake and regular voiding will be beneficial for cats with urolithiasis, UTI and various causes of UO. Urination outside the litter tray, which may be a sequela of LUT disease, is also a common problem behaviour in cats, who may benefit from improvement in the home environment (Figure 33).189,190 Cats suffering chronic pain for any reason can additionally benefit from species-specific improvement in the home environment.131,191,192
The below discussion focuses on pivotal aspects of MEMO and environmental resource provision/enrichment. Further insights into cats' environmental needs, and ways in which
Urination outside the litter tray is a common problem behaviour that may or may not be due to lower urinary tract disease. Environmental changes are likely to be beneficial; for example, the litter tray in this image may be inadequate in size and an open tray could be trialled. Image courtesy of Rachel Korman
the veterinary team can help caregivers to accommodate them, are available in the 'AAFP and ISFM feline environmental needs guidelines'. 188
Caregiver role and communication
Caregivers play a key role in the management of most LUT diseases, and effective communication is vital to ensure adherence with recommendations and successful outcomes, particularly for cats with FIC, 37 but also potentially other LUT diseases. Caregivers may provide long histories, show frustration and have anxiety for the welfare of their pet. They may have used various forms of punishment with their cat, which will have done nothing to improve litter tray avoidance and will likely have increased the cat's stress.
'Caregiver burden' (the strain of providing care for an unwell pet) 193 is present in those caring for cats with LUT disease. In a recent survey of veterinarians in the USA, challenges with caregiver compliance and expectations were selected as barriers to achieving a posi-tive outcome in cases of FIC by 81% and 62% of respondents, respectively. 54 Therefore, an open, attentive, empathetic communication style, offering credible explanations for the cat's problems, likely improves outcomes, and involving the whole veterinary team will enhance the care of affected cats.13,194A questionnaire for caregivers of cats with LUTS, and a caregiver guide to caring for a cat with LUT diseases that aims to complement care-giver communication and improve understanding, are available in the supplementary material. Veterinary behaviourists and qualified consultants can also serve an important role in helping improve the cat's environment and litter tray usage.
Caregiver burden can be heightened by the requirement to administer medications, 195 which are commonly prescribed to cats with LUT diseases. Forced medicating can also cause stress to this vulnerable group of cats. Careful prescribing and adherence to the following advice can improve compliance:
✜ Prioritise the most important medications for cats who are hard to medicate.
✜ Give caregivers options as regards medication formulation (liquid, tablet, capsule), based on individual cat preferences and caregiver capabilities.
✜ Demonstrate how to medicate, or explain how to hide/crush medication in treats (preferable to build positive associations), providing appropriate resources (online or hard copy).
✜ Avoid hiding medication in main meals, as this can cause hyporexia (particularly with bitter medications).
✜ Follow up with caregivers after 24/48 h to discuss any challenges and offer alternative approaches.
Environmental modifications
Caregiver changes in the home can have a significant impact on LUT diseases. Aspects relating to a cat's environmental needs that should be discussed are summarised in Figure 34 and reviewed below. This may necessitate a longer consultation or a follow-up telephone call and caregivers should also be directed to appropriate sources of online and/or hard copy information.
Summary of areas of focus for caregivers of cats with lower urinary tract disease. Adapted, with permission from Mikel Delgado
Secure resting opportunities
A private, secure, raised resting area can give a cat a sense of seclusion and safety. 188 In multi-cat homes, there should be an adequate number of separated locations for all the cohabiting cats. Options include beds on shelves (Figure 35), hammock-style raised beds, beds designed with areas to hide and to perch, and scratching posts/trees with concealed resting areas; even simple cardboard boxes can suffice. For cats with mobility problems, steps or ramps should be provided to enable access to higher locations.
Options to allow resting and perching in elevated locations should be provided. Image courtesy of Mikel Delgado
Litter tray management
Litter tray management should be explored with the caregiver, examining numbers and location of trays, litter substrate, cleaning regimen and so on. Inadequate litter tray provision can result in urination outside the litter tray and/or less frequent urination, with the cat retaining urine for longer than desirable. Key aspects of optimal litter tray provision include: ✜ Large enough trays for the size of the cat(s) (Figure 36). 196
A large litter tray made from a storage box with soft litter. Several such resources, placed in quiet locations and scooped daily, can encourage use. Image courtesy of Mikel Delgado
✜ The option of 'open' or 'closed' trays, according to cat preference. 148
✜ Easy entry (eg, lowered sides for cats with mobility problems), avoiding top-entering trays.
✜ Adequate numbers (one tray per cat plus one).
✜ Carefully selected locations. Trays should be located in quiet areas in the cat's main living space, with at least one on each storey of the house, away from food and water resources.
✜ Use of sandy, clumping-style litter (generally preferred by cats).
✜ Attention to tray cleanliness. Deposits should be regularly removed (at least once or, ideally, twice daily), 197 and trays should be completely emptied, cleaned with a mild detergent and rinsed with hot water every 1-2 weeks (sooner if soiled).
Cats with LUT diseases may suffer pain on urination and associate this with the litter tray.
(Offering an additional choice - in the form of a new tray in a different location with novel substrate - may be helpful in these instances; however, this should only be carried out once the cat's signs have resolved and any pain has been addressed. Cats with outdoor access can be provided with a 'latrine' area with a soft rakeable substrate (sand or soil) in a quiet part of the garden (Figure 37). Cats with outdoor access can also benefit from an indoor litter tray to use as needed (eg, in inclement weather).
Outdoor latrine in a quiet area with a rakeable surface to encourage regular voiding.
Food and water bowls
There are various means of encouraging water intake (Box 12), which is likely to benefit cats with all forms of LUT disease.13,46 Caregivers can also be directed to International Cat Care's resource 'Encouraging your cat to drink: a guide for caregivers', available at icatcare.org/cat-advice/cat-carer-guides, for detailed information.
As with water sources, cats in multi-cat homes should be offered at least as many feeding stations/bowls as there are cats in the home. Food dishes should be positioned in quiet locations offering privacy, out of view of other cats.
Other resources
Options for vertical and horizontal scratching should be provided, ensuring adequate numbers in multi-cat homes; locating these resources close to sleeping areas and to the perimeter of the cat's territory, as well as in areas where furniture has been scratched, will encourage use. 198 Climbing structures and self-play toys, along with puzzle feeders (Figure 39), can provide environmental enrich-ment.199,200 For cats without outdoor access, a feline patio ('catio') or supervised outdoor exploration using a harness and lead may be considered; the latter option requires careful introduction and training (see go.jfms.com/training_ harness). 201
Water intake should be encouraged for cats with any type of lower urinary tract disease; for example, using a water fountain. Image courtesy of Rachel Korman
Human-cat interactions
The aim in all interactions is to reduce the cat's protective emotions and encourage engaging emotions.
✜ Daily interactive playtime provides exercise, which may have anxiolytic effects. 188 Moreover, interactive playtime provides an outlet for species-typical behaviour (hunting) and may benefit the human-animal bond. 202
✜ Positive reinforcement-based training can provide mental stimulation and positively impact the caregiver-cat relationship.203,204 The aim may be to impart basic skills (eg, train the cat to go into their carrier or to accept grooming such as nail trims), encourage relaxation behaviours (eg, sit/stay), or simply have fun (parlour tricks such as 'high five').
✜ Grooming/brushing can likewise be a positive experience, if the cat enjoys it. Each cat's limits/preferences (eg, in regard to handling and petting) must always be respected.
✜ Avoidance of physical or other forms of punishment (eg, spanking, yelling, squirting with water bottles) is paramount. Punishment increases fear and stress and is not a humane or effective way to change behaviour.
Puzzle feeders can provide environmental enrichment and some types, such as the one pictured here, can be used with wet food for cats with lower urinary tract diseases. Image courtesy of Samantha Taylor
Scent and pheromones
Cats are extremely scent-sensitive, 190 and pheromones play an important role in commu-nication. 205 Feline synthetic pheromones have been shown to reduce anxiety, 206 scratching behaviour 207 and urine spraying. 208 An early pilot study evaluating facial pheromone fractions in cats with recurrent FIC found no significant decrease in the duration of clinical signs in the pheromone group, but there was a trend towards fewer episodes, shorter episode duration, and less aggression and fear behaviour. 209 Therefore, while not appropriate as a sole treatment, pheromone therapy may be useful as an adjunctive management tool for cats with FIC.
In addition, because the feline sense of smell is so highly sensitive, caregivers should avoid using heavily scented products in the cat's environment (eg, incense, scented candles, strong cleaning agents).
Intercat tension (inside and outside the home)
Intercat tension is common and may affect feline welfare. 201 Social tension between cats in multi-cat households, as well as tension involving cats outside the home, could contribute to stress and trigger or exacerbate LUT diseases. The '2024 AAFP intercat tension guidelines: recognition, prevention and management' 201 describe interventions for addressing social tension or conflict among cats, based on a framework of 'five pillars of a healthy multi-cat environment'.
Summary points
✜ Dysuria, stranguria, periuria, pollakiuria and haematuria are clinical signs of LUT diseases and not diagnoses in themselves. Investigations are needed to determine the underlying cause. The most common LUT disease is FIC, but other conditions such as urolithiasis should be excluded in cats with LUTS.
✜ Urinalysis and imaging are particularly useful in the investigation of LUTS.
✜ FIC should be considered a systemic disorder involving organs in addition to the bladder. FIC affects susceptible cats living in provocative environments and is optimally managed using MEMO (multimodal environmental modification) including changes to the cat's environment to decrease activation of the central threat response system.
✜ Struvite and calcium oxalate (the most common uroliths) are usually sterile and may not always be associated with crystalluria of the same composition.
✜ UTI is a less common cause of LUTS, particularly in otherwise healthy adult cats, and the finding of subclinical bacteriuria does not warrant antibiotic treatment.
✜ UO is a life-threatening and painful complication of certain LUT diseases. Optimal management involves catheterisation, analgesia, investigation and treatment of the underlying cause, and appropriate follow-up care to avoid recurrence.
✜ An environment that is not meeting a cat's needs should be considered a risk factor for LUTS.
✜ A cat's relationships (with humans and/or other cats/animals inside or outside the home) can be a source of environmental stress and should be explored in patients exhibiting LUTS
Conclusions
LUTS are a common reason for cats to be presented to the veterinary clinic. There are many underlying causes, the most’ common being FIC, followed by urolithiasis and UTI. These Guidelines refer to these as LUT diseases and have deliberately avoided the (outdated) term 'FLUTD', which is not a diagnosis in itself. The consequences of LUT diseases include UO, which can be life-threatening. Management of LUT diseases should involve a combination of medical, including analgesic (these are painful conditions), and behavioural interventions, recognising that FIC is the bladder's manifestation of a systemic disease. and/or consultancy work; however, none of these activities cause any direct conflict of interest in relation to these Guidelines.
Supplemental Material
Supplemental Material
Questionnaire for caregivers of cats with lower urinary tract signs
Supplemental Material
Supplemental Material
Understanding urinary tract diseases and how to help cats at home: a guide for caregivers
Footnotes
Acknowledgements
Grateful thanks to Victor Nores, of Lumbry Park Veterinary Specialists, for his contributions to, and review of, the imaging sections in these Guidelines.
Supplementary material
The following supplementary material files are available at go.jfms.com/LUTD_GLs_2025:
✜ Questionnaire for caregivers of cats with lower urinary tract signs.
✜ Video demonstrating the sacrococcygeal epidural (coccygeal block) technique in cats. Courtesy of Rachel Korman, Veterinary Specialist Services and Cat Specialist Services.
✜ Understanding urinary tract diseases and how to help cats at home: a guide for caregivers.
Conflict of interest
Members of the panel have received financial remuneration for providing educational material, speaking at conferences
Funding
The members of the panel received no financial support for the research, authorship, and/or publication of this article.
Ethical approval
This work did not involve the use of animals and therefore ethical approval was not specifically required for publication in JFMS.
Informed consent
This work did not involve the use of animals (including cadavers) and therefore informed consent was not required. For any animals or people individually identifiable within this publication, informed consent (verbal or written) for their use in the publication was obtained from the people involved.
References
Supplementary Material
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