Factors Related to the Occurrence of Feline Lower Urinary Tract Disease (FLUTD) in Salvador, Bahia, Brazil
R.O.G. Gama; D.O. Fernandes; C.C.V. Lima; S.M. Barrouin-Melo
Lower urinary tract diseases are common in domestic cats. The clinical manifestations include periuria, pollakiuria, hematuria, dysuria, strangury, crystalluria and urethral obstruction (Osborne et al. 2004). Feline lower urinary tract disease (FLUTD) or feline urologic syndrome (FUS), are commonly used terms to describe a series of changes without identifying the underlying etiology (Hostutler et al. 2005). However, they may be from different causes, such as congenital, neoplastic, bacterial, parasitic, iatrogenic, metabolic, neurological, uroliths and even idiopathic (Osborne et al. 1995 & Wouters et al. 1998). Because the urinary tract of cats responds to injury in a limited and predictable way, the clinical signs are similar, independently of the underlying pathology (Osborne et al. 1995). FLUTD morbidity may reach 10% or more (Osborne et al. 1995). Domiciled and sedentary cats, eating dry food and living with other animals are most commonly affected by urinary diseases (Gunn-Moore 2003 & Hostutler et al. 2005), being the highest occurrence of FLUTD observed in cats from two to seven years old (Lekchroensuk et al. 2001; Reche Jr. et al. 1998; Ross, 1990 & Willeberg, 1984). The disease is uncommon in cats under one year old and above 10 years of age (Willeberg 1984). Although there is no racial predisposition to the development of FLUTD, breeds such as Persian, Himalayan and Russian Blue have been considered predisposed to urolith formation as the cause of obstructive disease (Lekchroensuk et al. 2001). Males and females equally develop urinary uroliths (Ross 1990 & Willeberg 1984), but the obstructive disease is rare in females (Hostutler et al. 2005) and common in male cats, due to the anatomy of penile urethra (Hostutler et al. 2005; Reche Jr. et al. 1998 & Ross 1990). Castration of both sexes is considered one of risk factors for the development of FLUTD, because of its association with inhibition of urethral growth, induction of weight gain and a sedentary lifestyle (Ross 1990). Nevertheless, some authors have proposed that the reproductive status is not an important factor for the development of FLUTD (Reche Jr et al. 1998). Dried industrialized cat food has been considered as a dietary factor associated with the development of FLUTD, as they tend to alkalinize the urine, leading to formation of struvite crystals (Skoch et al. 1991). Clinically apparent lower urinary tract diseases occur more often in indoor cats and multicat households, being environmental stress highly associated with the onset of clinical signs of FLUTD (Buffington et al. 1999). The high incidence and morbidity of the disease, as well as the severity of some cases, mainly the ones associated with urethral obstruction, justify the importance of the knowledge of regional causes of FLUTD in Brazil, where studies on its epidemiology are scarce. The present study aims to characterize the factors associated to FLUTD in our geographic area and conditions, in order to highlights differences in relation to the world literature on the subject.
Materials and Methods
Thirty five cats presented clinical signs for FLUTD, namely hematuria, dysuria, pollakiuria, periuria or urethral obstruction out of a total of 244 cats seen at Veterinary Hospital of the Federal University of Bahia (HOSPMEV-UFBA) in Salvador-BA, from March 2006 to November, 2008. Data on those 35 animals were analyzed regarding the presence or absence of urethral obstruction, sex, age and breed, diet, reproductive status and presence of coexistence of other animals at home. Age data were separated in four groups: under one year; from one to three years; from four to six years; and over seven years old. Regarding to diet, the data were divided in three groups: animals that received commercial dried food, homemade food, or both.
In the present study, 14% (35/244) of all cats seen at the HOSPMEV-UFBA presented clinical signs of FLUTD. Thirty two cats were males (91%) and three were females (9%), being 25 (71%) of them intact and 10 (29%) castrated. Dysuria, hematuria and urethral obstruction were the most common clinical signs. Urethral obstruction corresponded to 63% of all cases, 100% in male cats, being 32% of those male cats castrated. Most animals (57%; 20/35), were of no specific breed (mongrel), 23% (8/35) were Siamese and 20% (7/35) were Persians. The age of highest occurrence was between one and three years old--66% (23/35); 10 animals were between four and six years (29%) and only two (5%), were aged above seven years old. No cat was younger than one year old. Twenty eight animals received only dry commercial food (80%); one (3%) received homemade food, and six cats (17%) received both, homemade and commercial dry food. Twenty three symptomatic cats (66%) were living with other animals at home (dog or cat) and 12 (34%) were the only pet at home.
There was a high occurrence of FLUTD in cats seen at HOSPMEV-UFBA within the period of study, of 14%, in comparison with the findings reported in the literature (Osborne et al. 1995). 91% of the clinically ill cats were male, In this group were 100% of animals that had urethral obstruction. This finding contrasts the data of Ross (1990) and Willeberg (1984), who concluded that males and females are equally affected. This fact can be explained by this study have a higher number of cats with urethral obstruction (63%). The urethral obstruction is the most obvious clinical heart disease, thus leading to greater concern of the owner to seek veterinary service (Reche Jr. et al. 1998). Some of the other clinical signs such as periuria, hematuria and dysuria, sometimes go unnoticed by the owner. No breed predisposition was observed in our study, as already described (Lekchroensuk et al. 2001), since the frequency of FLUTD in Siamese and Persian cats reflected the presence of those most popular cat breeds in our area. The highest frequency of FLUTD was at the ages between one and three years (66%), followed by the ages between four and six years old (29%). These data agreed with the findings of several authors (Buffington 1994; Lekchroensuk 2001; Reche Jr. 1998; Ross, 1990 & Willeberg 1984). Orchiectomy and ovariohysterectomy are common procedures in our area, adopted for reproductive control of cats in order to avoid overpopulation, being castration considered as a risk factor of FLUTD (Ross 1990). However, the majority of the clinically ill cats evaluated in the present study were not castrated, as previously showed (Reche Jr. et al. 1998). Even among cats that presented urethral obstruction, 68% of the animals were not castrated. In our study, 80% of the animals received only commercial dried food. Animals receiving industrialized dried diet are prone to FLUTD (Skoch et al. 1991; Gunn-Moore 2003; Hostutler 2005). Cats that eat dried industrialized diet, which is includes cereals, tend to alkalinization of urine, which predisposes the formation of struvite crystals (Skoch et al. 1991). Struvite crystals were found in 78% of cats with clinical signs of FLUTD (Reche Jr. 1998). However, justify the urine alkalinization only by ingestion of industrialize dried diets is a mistake, because not all animals receive industrialized dried diet produces urine with alkaline pH, this was observed by Reche Jr. 1998. Buffington & Chew (1996) described a mechanism of urinary alkalization in cats in response to stress. Studies show that environmental stress can trigger the onset of clinical signs of FLUTD (Buffington et al. 1999). Among the major factors of stress are the formation of environments with many animals (Willeberg, 1984). In this study 63% of owners had more than one animal in his home. The mere presence of other animals can characterize the stress factor for some cats, but we need more studies in order to correlate the formation of environments with many cats with the appearance of clinical signs of FLUTD.
As depicted from our observations, FLUTD can affect both males and females, of any breed, and is more frequent between one and six years of age. The obstructive disease was absent in females. Castration did not seem to be associated with the development of the disease, even among the animals that presented obstructive disease. Further studies are required in order to correlate the FLUTD with some suggestive risk factors, such as the intake of dried industrialized diets and stress due to dwelling with many animals.
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