Introduction
Feline lower urinary tract disease (FLUTD) is a common syndrome in small animal practice (Lund, Rimstad, and Eggertsdottir 2012). Where appropriate investigations fail to identify a specific cause, a diagnosis of FIC is made.
FIC accounts for between 55-73% of all cases seen for FLUTD (Buffington et al. 1997; Gerber et al. 2005). Although FIC is seen in all ages, cats 2-7 years old are at a higher risk (Lekcharoensuk, Osborne, and Lulich 2001). Certain risk factors have been identified for the development of FIC. Reported risk factors include male cats, longhaired cats, overweight, environmental stress, and feeding dry cat food (Buffington et al. 1997; Cameron et al. 2004; Defauw et al. 2011; Gerber et al. 2005).Local bladder abnormalities and/or neurohormonal changes have been observed in a proportion of cats affected by FIC. Local bladder abnormalities identified in some affected cats include a decreased concentration of glycosaminoglycans (GAGs) in the urine (Buffington et al. 1996). It is thus possible that deficiencies in the mucopolysaccharide layer that overlies the bladder epithelium may contribute to damage, ulceration, and increased permeability of the underlying epithelium and also to submucosal haemorrhage (Lavelle et al. 2000). Similar to humans with interstitial cystitis, a number of neuro-hormonal abnormalities have also been detected in cats with FIC that might play a role in the pathogenesis of the condition, including an increase in plasma norepinephrine (NE) and dihydroxyphenylalanine (DOPA) concentrations but without a concomitant increase in cortisol or adrenocorticotrophic hormone (ACTH) (Westropp, Kass, and Buffington 2006). These findings lend support to the fact that FIC appears to be associated with a stress response in many cats, but also suggests an uncoupling of the normal stress responses with increased sympathetic stimulation but suppressed adrenocortical responses (Westropp, Welk, and Buffington 2003).
Periuria (urinating in inappropriate locations), pollakiuria, stranguria, and gross hematuria are the most common clinical signs. Remarkably, these lower urinary tract signs subside within 1-7 days without therapy in up to 91% of cats with acute nonobstructive FIC. Signs recur after variable periods of time and again subside without treatment. Approximately 40-65% of cats with acute FIC will experience one or more recurrences of signs within 1 to 2 years (Defauw et al. 2011). A small subset of cats with FIC has also been described in which clinical signs persisted for weeks to months or are frequently recurrent. These cats are classified as having chronic FIC. Fortunately, less than 15% of cats evaluated because of acute FIC will develop chronic forms of the disease (Defauw et al. 2011).
It is important to recognize that cats with FIC often have clinical problems outside the lower urinary tract. The comorbid conditions frequently encountered are related to the gastrointestinal tract, skin lesions (barbering of caudal abdomen), cardiovascular system, endocrine system (low adrenal cortical function), behavior problems (frightened, withdrawn, hiding, aggressive, overly attached) and obesity (Buffington 2004).