Page 222 - Problem-Based Feline Medicine

214 PART 4 CAT WITH URINARY TRACT SIGNS

● Calcium oxalate crystals are typically “dumb- immunodeficiency virus infection, or neoplasia
bell”-shaped (monohydrate) or are “square- (see page 228, The Cat With Inappropriate
shaped with an ‘X’ in the center” (dihydrate), and Urination).
occur in an acidic pH. ● Occasionally pyuria occurs without an infection.
● Urate crystals are typically yellow or brown and
Inflammation of the lower urinary tract is usually
amorphous, and occur in an acidic pH.
associated with stranguria, dysuria, pollakiuria
● Cystine crystals are six-sided, and occur in an
and/or inappropriate urination; however, clinical
acidic pH.
signs may be absent.
● Other crystals include other minerals (calcium
phosphate), normal metabolites (leucine, bilirubin, Inflammation of the kidneys/ureters may be associ-
tyrosine) or drugs (iodinated contrast media, sulfa- ated with systemic illness (fever, vomiting, renal pain
containing antibiotics). and/or anorexia).
Crystals may be present as artifact.
● Crystals may form due to a change in pH or tempera-
Diagnosis
ture after collection; struvite crystals commonly
form in healthy cats if the urine is allowed to cool to Urine is white or cloudy.
room temperature or colder (as with refrigeration).
Microscopic examination of urine sediment reveals
● Crystals may also occur if the urine sample is
increased numbers of WBC (typically > 50–100/hpf).
allowed to evaporate.
● Normal urine contains < 3–5 WBC/hpf.
● For accurate interpretation, a complete urinalysis
● The significance of cell counts should be consid-
including microscopic examination of sediment
ered in association with the urine specific gravity.
should be done on a freshly collected sample in
order to avoid artifact. Nitrite and leukocyte test pads present on some urine
dipsticks are not reliable and should not be used.
PYURIA**

Classical signs LIPIDURIA
● Cloudy white or white urine.
Classical signs
● Stranguria, pollakiuria if inflammation
involves lower urinary tract. ● White urine.
● Fever, vomiting, renal pain if inflammation ● Not usually associated with a systemic
involves upper urinary tract. disease although may be associated with
lipid metabolism abnormalities.
See main reference on page 187 (The Cat Straining to
Urinate) for details on bacterial cystitis and page 225 (The See main reference on page 425 (The Yellow Cat or
Cat With Inappropriate Urination) for pyelonephritis. Cat With Elevated Liver Enzymes) for details on
hepatic lipidosis and page 569 (The Cat With Hyper-
lipidemia).
Clinical signs
Pyuria is indicative of inflammation.
● This is usually associated with an infectious Clinical signs
process.
Lipiduria may result in white urine.
– Bacterial infection is most common.
– Funguria is rare and is usually associated with a Lipiduria is not usually associated with clinical signs;
decrease in the host defense mechanisms such as it appears to be normal in some cats particularly those
diabetes mellitus, urolithiasis, chronic antibiotic that are obese and consuming normal or increased
administration, feline leukemia virus or feline amounts of dietary fat.