Page 903 - Small Animal Clinical Nutrition 5th Edition

Feline Lower Urinary Tract Diseases 935

VetBooks.ir Table 46-10. Reported risk factors for selected feline lower urinary tract diseases.* Calcium oxalate uroliths
Parameters
Feline idiopathic cystitis
Struvite uroliths
Four to 10 years old
Patient characteristics
Breeds (Table 46-7)
Breeds (Table 46-7)
Breeds (purebred, longhaired, Younger cats (<7 years) Older cats (>7 years)
Persian) Female Male
Neutered Neutered Neutered
Overweight Urinary tract infection
Lazy/little exercise (urease positive)
Environmental conditions Multi-cat household Indoor environment
Less freedom to leave house
Provided with litter box
Living in conflict with another cat
Moving within last three months
High number of rainfall days in
month before signs
Nutritional factors Fed dry cat food Alkalinizing foods (urinary pH >6.5) Dry foods 7 to 7.9% moisture
Decreased water intake Magnesium content 0.14 to 0.56% Excessively acidifying foods
(0.36 to 1.4 mg/kcal) (urinary pH = 5.8 to 6.29)
Phosphorus content 1.27 to 1.88% Feeding single brand
(3.17 to 4.70 mg/kcal) Sodium content 0.2 to 0.3%
Sodium content 0.57 to 1.48% (0.48 to 0.77 mg/kcal)
(1.43 to 3.7 mg of Na/kcal) Potassium content 0.04 to
Fiber content ≥2.7 0.06% (0.95 to 1.6 mg/kcal)
(≥0.71 g/100 kcal) Protein content 21 to 32%
(5.15 to 7.98 g/100 kcal)
Magnesium content 0.04 to
0.07% (0.09 to 0.18 mg/kcal)
or 0.14 to 0.56% (0.36 to 1.4
mg/kcal)
Phosphorus content 0.34 to
0.70% (0.85 to 1.76 mg/kcal)
or 1.27 to 1.88% (3.17 to 4.70
mg/kcal)
Calcium content 0.39 to
0.82% (0.97 to 2.05 mg/kcal)
or 1.5 to 2.0% (3.76 to 5.06
mg/kcal)
*Nutrient values expressed on a percent dry matter basis and assume a food energy density of 4 kcal metabolizable energy/g (17.6 kJ/g);
however, dry matter nutrient content of foods with energy densities substatially higher or lower than 4 kcal/g will be under- or overreresent-
ed, respectively. Thus, the energy basis nutrient values in this table (parenthetical values) are more accurate.

and found that qualitative methods yielded false-negative re- used: the “nidus” is where growth of the urolith apparently
sults in 38.1% of the uroliths and false-positive results in 6.7% started; it is not necessarily the geometric center. “Shells” are
(Ulrich et al, 1996). These two methods agreed in only 43.1% one or more complete outer layers of the urolith. “Surface crys-
of the analyses. Uroliths, therefore, should be analyzed quanti- tals” refer to an incomplete outermost layer. Grossly visible lay-
tatively to obtain the most accurate information about mineral ers do not always mean different mineral composition.The lay-
content. ers represent different phases of deposition and may be com-
Quantitative analytical methods include optical crystallogra- posed of the same or different minerals.
phy, x-ray diffraction, infrared spectroscopy and electron scan-
ning microscopy (Ulrich et al, 1996). In optical crystallography, Risk Factors
crystalline material is removed from representative areas of the Many studies have evaluated risk factors for FLUTD includ-
urolith using a dissecting microscope. The optical characteris- ing patient characteristics, environmental conditions and var-
tics (e.g., refractive index and birefringence) of the crystalline ious nutritional factors (Table 46-10) (Buffington et al, 1997,
material then are determined by polarizing microscopy and 2006; Houston et al, 2003; Kirk et al, 1995; Cameron et al,
compared with known standards to determine mineral compo- 2004; Lekcharoensuk et al, 2000, 2001, 2001a; Walker et al,
sition. Methods such as infrared spectroscopy are used if results 1977; Jones et al, 1997; Thumchai et al, 1996). For some risk
of optical crystallography are inconclusive. factors, findings are consistent between studies, whereas oth-
Different minerals may be deposited in layers (i.e., com- ers are different (e.g., living in a multi-cat household has been
pound) or mixed throughout the urolith. Although one miner- associated with increased risk of FIC in some studies but not
al type predominates, the composition of uroliths frequently is in others). It is important to keep in mind that risk factors
mixed. Thus, sampling and reporting results from different identified in epidemiologic studies show associations between
parts of the urolith become important when considering urolith certain factors and the disease of interest; additional study is
dissolution and prevention.The following terms are sometimes necessary to show a cause-and-effect relationship. For exam-