Page 215 - Problem-Based Feline Medicine

13 – THE CAT WITH DISCOLORED URINE 207
207

● Pale yellow or colorless urine*** (p 207)
● Dilute urine*** (p 215)
*Occurs with polyuric states; *most common causes of PU/PD are renal failure, diabetes mellitus,
and hyperthyroidism; *other clinical signs may be present and relate to an underlying disorder.

● Blue or green urine (p 207)
*Drug discoloration; *occurs with some drugs or dyes especially methylene blue.

INTRODUCTION – Blood (hematuria) is present when centrifuged or
settled urine is clear with a red sediment at the bot-
tom of the tube, or there are > 10–20 red cells/HPF
MECHANISM? on microscopic examination of sediment.
– Hemoglobin is present if the urine remains pink
Urine that is anything other than yellow is abnormal.
after centrifugation or on settling, few red cells
● Normal urine is typically transparent and yellow
(< 10 RBC/HPF) are evident on microscopic
or amber on visual inspection.
examination of the sediment, and there is clini-
● Two pigments, urochrome and urobilin, impart the
cal and hematologic evidence of hemolytic ane-
yellow color.
mia. Plasma has a reddish discoloration.
● The intensity of the yellow color is in part related to
– Myoglobin is present if the urine remains pink
the volume of urine collected and concentration of
after centrifugation or on settling, few red cells
urine produced.
are evident on microscopic examination of the
● Significant disease may exist when urine is normal
sediment, and there is clinical and biochemical
in color.
evidence of muscle damage. Plasma is clear.
Abnormal urine color is caused by the presence of
Clinical signs associated with discolored urine will
several endogenous or exogenous pigments, and indi-
aid in diagnosis.
cates a problem.
● Hematuria (red or pink urine) indicates urinary
● Pink, red, brown, orange or black urine suggests
tract disease (upper or lower) or bleeding disorders.
the presence of blood, hemoglobin, myoglobin or
– Signs that suggest the cause is lower urinary
bilirubin.
tract disease are stranguria, pollakiuria and
● Cloudy or white urine suggests the presence of
dysuria (urine may be pink, red, brown, orange
pus, lipid or crystals.
or cloudy in color).
● Pale yellow or colorless urine is associated with
– Signs that suggest hematuria is from upper uri-
decreased urine concentration and increased
nary tract disease include polyuria and polydip-
urine volume.
sia (urine is usually pale yellow or colorless,
● Blue or green urine is uncommon, and is usually
however, cloudy or red urine may occur).
associated with excretion of drugs or toxins.
–A bleeding disorder is indicated by evidence of
Owners may observe discolored urine in the litter box bleeding from other sites.
or in areas of inappropriate urination. – Hemoglobin in urine suggests intravascular
hemolysis. Marked hemoglobinuria may
Examination of urine sediment (for red blood cells) and
occur in kittens with neonatal isoerythrol-
plasma or serum color will aid diagnosis.
ysis. Hemoglobinuria rarely occurs with
Whole blood, hemoglobin and myoglobin all give a Hemobartonella infection and immune-medi-
positive reaction on the blood test pad on dipsticks. ated anemia, which present mainly as extravas-
● These can be distinguished as follows: cular hemolysis.