OCCURRENCE AND OUTCOMES OF UROLITHIASIS AND OTHER URINARY TRACT CONDITIONS IN DOMESTIC CATS.

This was a retrospective study that covered a 10-year period from January 2009 to December 2018. The objectives of this study were to determine 1) the prevalence, 2). the clinical manifestations, diagnostic approaches and diagnoses, as well as 3). the treatments and outcomes of urolithiasis and other urinary tract conditions in domestic cats in Nairobi County, Kenya. Clinical data of all cases of cats was collected from five (5) purposively selected veterinary clinics. All cases with history of urinary tract condition were isolated from the pool. For each of these cases with urinary system problems, specific data was retrieved, which included breed, sex, age, weight, neuter history, clinical signs, diagnostic methods employed and confirmed diagnosis, methods of treatment whether medical or surgical, drugs used, site of uroliths and other urinary tract conditions diagnosed, post-treatment care and the outcome of each case. Prevalence of each of the conditions was determined. Proportions were determined for categorical variables i.e. sex, breed and neuter history. Ranges, means and standard deviations were determined for continuous variables i.e. weight and age. Univariate and multivariate analysis was done to determine the actual factors that were most likely to be associated with the occurrence of urolithiasis.

The total number of domestic cat cases in the 10-year period was 4,404. The overall prevalence of urinary tract disease was 2.4% (n=104) and that of urolithiasis was 0.6% (n=28). Out of the 104 cases with urinary tract conditions, 72.1% (n=75) had definitive diagnoses indicated in the case records, while in 27.9% (n=29) the definitive diagnoses were not indicated. Among the cases with indicated definitive diagnoses, urolithiasis was 37.3% (n=28) and idiopathic FLUTD was 22.7% (n=17). The cats presented with urinary tract conditions included 64.6% (n=62) males and 35.4% (n=34) females, while those with urolithiasis included 76.9% (n=20) males and 23.1% (n=6) females. Domestic shorthair breed was the most (77.3%, n=68) affected by various urinary tract conditions out of which 30.9% (n=21) had urolithiasis. Most (61.7%, n=50) cats with urinary tract diseases were sexually intact, while most (60.9%, n=14) cats with urolithiasis were neutered. The most common clinical manifestations of cats with urinary tract conditions were haematuria 40.4% (n=40) and dysuria 23.2% (n=24). Dysuria 37% (n=10) and haematuria 29.6% (n=8) were the commonest clinical signs of cats with urolithiasis. Diagnostic methods used in the 104 cases of urinary tract conditions were physical examination 75% (n=78), urinalysis 12.5% (n=13), imaging (including radiography and ultrasound) 38.5% (n=40) and cystotomy 11.5% (n=12).

Therapy for urinary tract conditions in this study included use of corticosteroids (37.2%, n=35), antibiotics [such as cephalosporins (21.3%, n=20), metronidazole 14.9%, n=14), tetracyclines (4.3%, n=4) and sulphonamides (2.1%, n=2). Lactated Ringer’s solution was used for fluid therapy in 20.4% (n=19) of the cases, normal saline (17.0%, n=16) and 5% dextrose (5.3%, n=5). Pain therapy was achieved using non-steroidal anti-inflammatory drugs (9.6%, n=9). The records indicated that 55.7% (n=39) of the cats recovered after treatment, recurrent cases were 17.1% (n=12) and 27.1% (19) of the cases died. Dysuria (OR=0.10; CI= 0.01 to 1.17; P=0.066), distended urinary bladder (OR=20.79; CI=2.32-186.22; P=0.007) and body weight (OR=16.45; CI=1.38-196.68; P=0.027) were factors significantly associated with urolithiasis in domestic cats.

The study concluded that urolithiasis was found to have the highest prevalence at 37.3% (n=28) among the urinary tract conditions in domestic cats in Nairobi County, Kenya, followed by idiopathic FLUTD and idiopathic cystitis each at 22.7% (n=17). There was a higher prevalence of idiopathic FLUTD, which may be due to lack of proper examination of cats with urinary tract problems. However, according to this study, most of the urinary tract conditions recovered after treatment. Further studies need to be conducted to chemically verify the type of uroliths affecting cats in Nairobi County, Kenya for proper management and prevention of occurrence of urolithiasis. There is need to also carry out a comprehensive research on the predisposing factors for urinary system conditions in domestic cats.

 

 

 

 

Figure 4.1: The Yearly trend of urinary tract conditions in domestic cats in the five veterinary clinics in Nairobi County from January 2009 to December 2018. 47

 

 

 

The urinary system is composed of the urethra, urinary bladder, kidneys and ureters. There are quite a number of urinary tract conditions in domestic cats, including urolithiasis, feline urologic syndrome (FUS), bacterial infection, cystitis, idiopathic cystitis, urethral obstruction and neoplasia (Mateescu et al., 2012). Cats are presented to the veterinary clinics and hospitals mainly due to such conditions (da Rosa et al., 2018). A veterinarian is likely to examine a cat for feline urologic syndrome, cystitis, renal disease, and inappetence (Lund et al., 1999). Clinical signs of urinary tract diseases in cats are non-specific and similar symptoms may manifest in diseases with different aetiology. Typical signs of urinary tract involvement are haematuria, dysuria, anuria, polyuria stranguria, pollakiuria and periuria, but rarely do these signs point out to a specific cause (Mateescu et al., 2012).

In USA, 8% of cats presented to hospitals suffer from feline lower urinary tract disease (FLUTD) (Gerber, 2008). Urolithiasis accounted for 22% of the cats suffering from FLUTD (Gerber et al., 2005) and 56.06% of cats with urinary tract diseases (Mateescu et al., 2012). In USA, the estimated prevalence of LUTD is approximately 1.5% (Hostutler et al., 2005). Previous studies have shown that urolithiasis accounted for 13-28% of the causes of non-obstructive urinary tract disease in referral institutions (Hostutler et al., 2005). Zohaib et al. (2013) indicates that 10 to 20% of cats suffering from LUTD have uroliths or urethral plugs. Occurrence of urolithiasis is estimated to be approximately 15 to 21% in cats with clinical signs of lower urinary tract disease (LUTD) (Hunprasit et al., 2019).

Urolithiasis is one of the urinary tract conditions reported in domestic cats and is a common cause of clinical signs linked to feline urinary tract (Lulich et al., 2011). By definition, urolithiasis is the occurrence and the effects of urinary calculi in the urinary tract. This condition is one of the causes of haematuria in cats (Popa et al., 2017). Uroliths commonly occur in the urinary bladder and the urethra. The predisposing factors for urolithiasis are multifactorial, which include hereditary, congenital and acquired pathophysiological factors. These factors can synergistically promote precipitation of urine-excreted metabolites to form uroliths (Lulich et al., 2011). Other factors that may contribute to urolithiasis are certain metabolic derangements, absence or reduction of natural crystallization inhibitors and urinary tract infections (Ling et al., 1998).

Higher incidences of urinary tract conditions were found in neutered 6 to 9 months old cats, but the cause of this occurrence for the specified age category was not determined (Howe et al., 2000). When urine becomes supersaturated with minerals and has conducive pH for crystallization, the minerals precipitate to form crystals that converge to form uroliths (Houston et al., 2003). The supersaturation of urine may be enhanced by factors such as urine retention of crystalloids, high urine specific gravity, increased mineral excretion in urine, and decreased natural inhibitors of crystallization (Houston et al., 2003).

Uroliths are composed of small amounts of organic matrix (mucoid material) and large amounts of crystalline material, which are either organic or inorganic crystalloids. They are classified based on the mineral content (Lulich et al., 2011). There are four types of uroliths that occur in cats, which include struvite (magnesium ammonium phosphate), calcium oxalates, calcium phosphate and urate. Uroliths can also be of mixed composition (Norsworthy, 2011). The type of calculi formed may vary depending on breed, age, geographical location and diet (Hunprasit et al., 2019). Struvites are the commonest uroliths in cats. Bacterial infections, especially Staphylococcus species or Proteus species induce a small percentage of struvite uroliths. Other types of uroliths are unrelated to bacteria, and their pathogenesis is not well known, but dietary factors are incriminated (Norsworthy, 2011). In some cases, cats with urinary cystic uroliths do not have crystals in their urine, while others may have crystals of different mineral content, which is rare (Houston et al., 2003).

Treatment of urolithiasis includes surgical removal of the uroliths, retrograde urohydropropulsion, dietary or medical dissolution of the uroliths, and antibiotic therapy of some bacteria-induced uroliths. Prevention of urolithiasis is done by increasing water intake, urine acidifying diets or urinary acidifiers in cases of non-infection struvite uroliths and non-acidifying diets with reduced sodium and protein to prevent occurrence of calcium oxalate uroliths (Norsworthy, 2011).

Some of the other common urinary tract conditions in domestic cats include lower urinary tract disease, cystitis, urethral obstruction, pyelonephritis and neoplasia. Lower urinary tract disease (LUTD) is a urologic syndrome consisting of multiple disorders including idiopathic cystitis, urolithiasis, urethral obstructions, bacterial urinary infections and tumours. It entails dysfunction of the urethra or urinary bladder.

Some of the common symptoms for this syndrome may include pollakiuria, stranguria, haematuria and periuria (Lew-Kojrys et al., 2016).

The prevalence, diagnosis, treatments and outcomes of urinary tract conditions in domestic cats in Kenya is not documented. This study therefore, is aimed at consolidating data related to these factors of urinary tract conditions; with emphasis on urolithiasis in domestic cats that have been presented for treatment in various veterinary clinics in Nairobi County, Kenya from January 2009 to December 2018. Publication of this data will give a guidance on the existing situation of domestic cat urinary tract disease, the methods of diagnosis, treatments and their outcomes in Kenya.

There is a likelihood of high occurrence of varied urinary tract conditions in domestic cats in Nairobi County, Kenya.

Uroliths are responsible for about a quarter of all cases of haematuria and dysuria in domestic cats, and the second commonest cause of lower urinary tract infection (Palma et al., 2009). They are the major cause of urethral obstruction in cats (George and Grauer, 2016). In Kenya, there is no study that has been conducted specifically on urinary tract conditions and urolithiasis in domestic cats. Therefore, there was need of a study to establish the status of the conditions in Kenya with emphasis on urolithiasis with respect to prevalence, clinical manifestations, diagnoses, treatments and outcomes. Publication of data from this study will facilitate veterinary practitioners in diagnosis, treatment, and judging of prognosis for domestic cats with urinary tract conditions.

 

To retrospectively determine the occurrence, clinical manifestations, diagnoses, treatments and outcomes of urinary tract conditions with emphasis on urolithiasis in domestic cats in Nairobi County, Kenya