Redefinition of the feline urologic syndrome: feline lower urinary tract disease with heterogeneous causes

Prevalence, Risk Factors, Pathophysiology, Potential Biomarkers and Management of Feline Idiopathic Cystitis: An Update Review

Feline idiopathic cystitis is a widespread disease in small animal clinics, which mainly presents with urinary signs like dysuria, stranguria, hematuria, pollakiuria, and periuria. The etiopathogenesis of the disease may involve interactions between the environmental stressors, neuroendocrine system and bladder of affected cats. Diagnostic biomarkers have not been tested in clinical studies though they are theoretically feasible, and since the clinical signs of the disease assemble those of other feline lower urinary diseases, its diagnosis is a procedure of exclusion. The primary treatment of the disease is long-term multimodal environmental modification (or enrichment) while anti-anxiety drugs and nutritional supplements are recommended for chronic recurrent cases. Still, many medicines need to be evaluated for their efficacy and safety. This review aims to provide readers with a comprehensive understanding of feline idiopathic cystitis by summarizing and updating studies concerning the prevalence, risk factors, etiological hypotheses, diagnostic procedures, possible treatments, and prognosis of the disease.

Stress and Feline Health

In the health sciences, stress often is defined in terms of stressors; events that are perceived as threats to one's perception of control. From this perspective, a stressor is anything that activates the central threat response system (CTRS). Recent research shows that the CTRS can be sensitized to environmental events through epigenetic modulation of gene expression. When CTRS activation is chronic, health and welfare may be harmed. Environmental modification can mitigate the harmful effects of chronic CTRS activation by reducing the individual's perception of threat and increasing its perception of control, which improves health and welfare.

Resurrecting FUS: Adrenal Androgens as an Ultimate Cause of Hematuria, Periuria, Pollakuria, Stranguria, Urolithiasis and Obstruction in Neutered Cats

Although many authors have doubted that “feline urological syndrome” (FUS) describes a real pathogenetic entity, because it subsumes such a large variety of signs, Sumner's recent finding that urethral obstruction occurs most frequently in springtime adds to a large body of evidence that lower urinary tract problems occur most commonly in late winter and spring. This suggests that FUS may be a unitary disorder, with a hormonal basis, driven by increasing day length. We argue that rising adrenal androgens (AA) in neutered cats induce stress, and other more concrete manifestations of FUS through androgen-driven mechanisms.

From FUS to Pandora syndrome: where are we, how did we get here, and where to now?

NEW CONCEPTS: Ideas about the causes of lower urinary tract signs (LUTS) in cats have changed significantly in the past 40 years. Recent research is challenging the conventional view that the bladder is always the perpetrator of LUTS, and suggests that the bladder can also be one victim of a systemic process associated with a sensitized central stress response system.

AIM

In this article the authors provide their perspective on the implications of these findings for the diagnosis and treatment of cats with LUTS, provide some historical context, and suggest ways that the veterinary profession might work together to better understand the disorders underlying these signs, and possibly reduce their prevalence.

Idiopathic cystitis in domestic cats--beyond the lower urinary tract

Signs of lower urinary tract (LUT) disease in domestic cats can be acute or chronic, and can result from variable combinations of abnormalities within the lumen of the LUT, the parenchyma of the LUT itself, or other organ system(s) that then lead to LUT dysfunction. In the majority of cats with chronic signs of LUT dysfunction, no specific underlying cause can be confirmed after standard clinical evaluation of the LUT, so these cats typically are classified as having idiopathic cystitis. A syndrome in human beings commonly known as interstitial cystitis (IC) shares many features in common with these cats, permitting comparisons between the two species. A wide range of similarities in abnormalities has been identified between these syndromes outside as well as inside the LUT. A variety of potential familial and developmental risk factors also have been identified. These results have permitted generation of the hypothesis that some of these people have a disorder affecting the LUT rather than a disorder of the LUT. This perspective has suggested alternative diagnostic strategies and novel approaches to treatment, at least in cats. The purpose of this review is to summarize research investigations into the various abnormalities present in cats, to compare some of these findings with those identified in human beings, and to discuss how they might modify perceptions about the etiopathogenesis, diagnosis, and treatment of cats with this disease. Dedication: I dedicate this contribution to Professor Dennis J. Chew, whose collaboration, patience, and support made it all possible.

A case of interstitial cystitis and Hunner's ulcer in a domestic shorthaired cat

An 8-year-old spayed, domestic, shorthaired cat was examined with signs of feline urological syndrome which were unresponsive to previous therapy with antibiotics and urinary acidifiers. Biopsy of the bladder revealed signs of cystitis similar to interstitial cystitis in humans. Treatment with sodium pentosan polysulphate resulted in a decreased frequency of urination and resolution of haematuria. This condition may be more widespread in cats than realised, as it is only by bladder biopsy that diagnosis can be made.

Disorders of sexual differentiation in puppies and kittens: a diagnostic and clinical approach

As in all domestic mammals, sexual differentiation in dogs and cats starts early in the embryonic period prenatally and continues into early postnatal life. The result of such a process is, however, not evident until after puberty,a time when the entire reproductive system undergoes significant changes. Normality of sexual differentiation is difficult to observe in neonates of small animals, with the only gender difference being a slightly longer anogenital distance in male (13-15 mm) versus female (7-8 mm)animals. Early diagnosis of deviations from normality can spare breeders the time and effort devoted to raising an animal that may turn out to be unsuitable for becoming part of the reproductive stock and may spare owners the concern for a pet whose health may be unnecessarily threatened by failing to remove a malformed reproductive system early in life. This article reviews the incidence, clinical and gross anatomic features,and diagnostic approaches that veterinarians can use to address inborn errors of the reproductive system of dogs and cats, highlighting those malformations that bear clinical relevance and may become manifest from birth until puberty.

Feline idiopathic cystitis: current understanding of pathophysiology and management

Many indoor-housed cats seem to survive perfectly well by accommodating to less than perfect surroundings. Neuroendocrine abnormalities in the cats we treat, however, do not seem to permit adaptive capacity of healthy cats, so these cats may be considered a separate population with greater needs. Moreover, veterinarians are concerned more with optimizing environments of indoor cats than with identifying minimal requirements for indoor survival. Further information about environmental enrichment and conflict is available at http://www.nssvet.org/ici/.

Epidemiologic study of risk factors for lower urinary tract diseases in cats

OBJECTIVE

To determine proportional morbidity rates (PMR) and risk factors for lower urinary tract diseases (LUTD) in cats.

DESIGN

Case-control study.

SAMPLE POPULATION

Records of 22,908 cats with LUTD and 263,168 cats without LUTD.

PROCEDURE

Data were retrieved from the Purdue Veterinary Medical Data Base. Descriptive statistics and univariate logistic regression analyses were performed to assess whether breed, age, sex, and neutering status were associated with different causes of LUTD.

RESULTS

Mean PMR for LUTD irrespective of cause was 8/100 cats (range, 2 to 13/100 cats). Increased risk for urocystolithiasis (Russian Blue, Himalayan, and Persian cats), bacterial urinary tract infections (UTI; Abyssinian cats), congenital urinary tract defects (Manx and Persian cats), and urinary incontinence (Manx cats) was detected. Cats between 2 and < 7 years of age had increased risk for urethral plugs, neurogenic disorders, congenital defects, and iatrogenic injuries. Cats between 4 and < 10 years of age had increased risk for urocystolithiasis, urethral obstructions, and idiopathic LUTD. Cats > or = 10 years of age had increased risk for UTI and neoplasia. Castrated males had increased risk for each cause of LUTD except UTI and incontinence. Spayed females had increased risk for urocystolithiasis, UTI, and neoplasia. Sexually intact females had decreased risk for each cause of LUTD except neurogenic disorders and iatrogenic injuries.

CONCLUSION AND CLINICAL RELEVANCE

Specific breed, age, sex, and neutering status may be associated with specific types of feline LUTD. Knowledge of patient risk factors for LUTD may facilitate development of surveillance strategies that enhance earlier detection.

Interstitial cystitis: a critique of current concepts with a new proposal for pathologic diagnosis and pathogenesis

Interstitial cystitis (IC) has continued to be an unresolved problem in clinical urology despite intense investigation over the past 16 or more years. Its etiology and pathogenesis are still undetermined, and its pathologic diagnosis is essentially one of exclusion, with no specific or clear criteria. In this review, current concepts of the etiology/pathogenesis and pathology are critically analyzed, new pathologic observations summarized, and a proposal of neurogenic inflammation as the primary pathogenetic factor is presented in the context of all currently available information. The popular postulate attributing IC to a deficient or defective glycosaminoglycan urothelial surface layer is not substantiated by morphologic, experimental, clinical, or therapeutic observations. Although the consensus seems to discount an infectious etiology, there is sufficient evidence that a microbial factor-short of a bona fide clinical infection-may have a role. Both autoimmunity and mast cell infiltration also appear to have a role, despite the lack of evidence that either is involved as the primary etiologic factor. Claims that the so-called feline urologic syndrome may represent a natural animal model of IC are shaky. As it now stands, there is no natural or induced animal model that duplicates IC as it occurs in humans. No specific or diagnostic light microscopic pathologic features are provided by either routine histopathology or immunohistochemistry. Increasingly, it has been recognized that detrusor mast cell count has little or no diagnostic value. On the other hand, electron microscopy has provided important new observations: (a) presence of mast cells, activated by piecemeal degranulation, in close proximity to intrinsic nerves-particularly in suburothelium: (b) distinctive pathologic changes in urothelium, suburothelium, and muscularis in biopsy samples obtained after diagnostic bladder hydrodistension; (c) constant associated changes in venules, capillaries, and neural elements in the same biopsy samples; and (d) diffuse involvement of bladder wall, with the most evident and profound pathologic changes in posthydrodistension biopsy samples obtained from cystoscopically obvious lesions (glomerulations). These features are sufficiently distinctive to allow definitive pathologic diagnosis of IC, and provide a firm basis for primary involvement of neurogenic inflammation in its pathogenesis. A proposal is presented regarding the mechanisms invoked by neurogenic inflammation. This proposal revolves around sensory nerve excitation, the release of neuropeptides, and activated differential secretion of potent mast cell mediators. This proposal can account for the heterogeneity and variability of observed pathologic features, and upholds the tacit acceptance of IC as a disease of pluricausal etiology and multifactorial pathogenesis.

Viral infections of the feline urinary tract

The exact cause of hematuria, dysuria, and urethral obstruction remains unknown in a large percentage of naturally occurring cases of feline lower urinary tract disease (FLUTD). One attractive hypothesis implicates viruses as the cause of some idiopathic forms of FLUTD; supporting this hypothesis is the fact that a gamma herpesvirus, a calicivirus, and a retrovirus have been isolated from urine and tissues obtained from cats with this type of disease. Although the clinical course and laboratory findings of cats with idiopathic FLUTD are suggestive of an infectious cause, the question of whether viruses have a pathologic role in some forms of naturally acquired FLUTDs has not been completely answered.

Feline lower urinary tract disorders. Definition of terms and concepts

Lower urinary tract disorders of male and female cats may be caused by a variety of fundamentally different causes. The term Feline urologic syndrome should be abandoned and substituted with descriptive etiopathogenic terms whenever possible. If the underlying cause cannot be identified, the term Idiopathic lower urinary tract disease is recommended.

The role of uropathogens in feline lower urinary tract disease. Clinical implications

Bacterial, fungal, and parasitic uropathogens have small but significant roles as causative agents in naturally occurring feline lower urinary tract disease. However, the exact cause of hematuria, dysuria, and/or urethral obstruction remains unknown in a large percentage of cats. Feline calicivirus, feline syncytia-forming virus, bovine herpesvirus-4, mycoplasmas, and ureaplasmas are potential uropathogens whose etiopathogenic roles in idiopathic feline lower urinary tract disease remain, as of yet, unresolved.

Effect of therapy on susceptibility to urinary tract infection in male cats with indwelling urethral catheters

Indwelling urinary catheters with a closed urine collection system were maintained in 30 male cats for 3 days after induction of irritant cystitis. All cats received subcutaneous fluids during the 3 days the catheters were in place. The effects of four different treatment regimens on urinary tract infection rates, incidence of urethral obstruction, and development of urinary tract lesions over a 10-day period were compared with results in a nontreated group. Treatments were 1) amoxicillin for 5 days PO; 2) prednisolone for 5 days PO; 3) both amoxicillin and prednisolone for 5 days PO; and 4) dimethylsulfoxide (DMSO) for 3 days intravesicularly. Euthanasia was done before the end of the 10-day experimental period if the cats had two bouts of urethral obstruction or if the cats became uremic for causes unrelated to urethral obstruction. Seven cats were euthanatized before the conclusion of the experiment. These cats had been treated with prednisolone, prednisolone and amoxicillin, or DMSO. All cats that received amoxicillin alone or no therapy survived the 10-day period. Mortality was due to repeated urethral obstruction or to uremia associated with pyelonephritis or papillitis. Urinary tract infection rate was similar in all groups. The group treated with prednisolone alone had the highest incidence of renal infection. Inflammatory lesions in the lower urinary tract were similar in all groups. In conclusion, persistent urinary tract infection often develops in cats with cystitis after indwelling urethral catheterization even when closed systems of urine drainage are used.(ABSTRACT TRUNCATED AT 250 WORDS)

The role of viruses in feline lower urinary tract disease

Viruses have been implicated as causative agents in the etiopathogenesis of some forms of feline lower urinary tract disease (LUTD). This hypothesis was supported by isolation of feline calicivirus, bovine herpesvirus 4 (strain FeCAHV), and feline syncytia-forming virus from cats with naturally occurring LUTD, and by experimental studies of induced viral urinary tract infection. Results of early clinical studies yielded contradictory results concerning the role of viruses in feline LUTD. However, recent detection of bovine herpesvirus 4 antibodies in feline serum samples and discovery of calicivirus-like particles in crystalline/matrix urethral plugs obtained from cats with naturally occurring LUTD, suggests the need to reexamine the etiopathologic role of viruses using contemporary methods of virus identification and localization.

Relationship of nutritional factors to the cause, dissolution, and prevention of feline uroliths and urethral plugs

Feline lower urinary tract disease is often associated with uroliths and urethral plugs. Uroliths and urethral plugs are composed of variable quantities of matrix and a variety of minerals (including struvite, calcium oxalate, ammonium urate, calcium phosphate, and cystine). Knowledge of nutritional factors associated with the pathophysiology of uroliths and urethral plugs facilitates the modification of diets for the dissolution of several minerals contained within them.