Page 219 - Problem-Based Feline Medicine

13 – THE CAT WITH DISCOLORED URINE 211
211

Classical signs—Cont’d BILIRUBINURIA**
● Hematuria may be only clinical sign if
Classical signs
upper urinary tract involved.
● Urine is dark yellow.
See main reference on page 191 for details on blad- ● Mucous membranes and skin are icteric.
der/urethral neoplasia and page 250 for details on renal
neoplasia. See main reference on page 421 (The Yellow Cat or Cat
With Elevated Liver Enzymes) for details on the
icteric cat.
Clinical signs

If the neoplasm involves the lower urinary tract, clini- Clinical signs
cal signs may include hematuria, stranguria, pollak-
Urine is dark yellow or brown from presence of
iuria and/or inappropriate urination.
bilirubin.
If the neoplasm involves the upper urinary tract,
Cat may be weak and icteric.
hematuria may be present; renomegaly may be pal-
pated. Mucous membranes are pale if associated with
hemolytic anemia.

Abdominal palpation may reveal hepatomegaly, hepatic
Diagnosis masses or the liver may not be palpable.

Most common lower urinary tract neoplasms Bilirubinuria may be associated with vomiting,
include transitional cell carcinoma and lym- anorexia, diarrhea and/or neurologic signs (seizure,
phoma. hypersalivation, tremors).
● Neoplastic cells may be present on microscopic
examination of urine sediment.
Diagnosis
● A bladder or urethral mass may be detected by
ultrasonography, contrast urethrocystography, ure- Bilirubinuria is diagnosed by a color change on the
throcystoscopy or cystotomy. bilirubin pad on a urine dipstick.
● Definitive diagnosis is made by fine-needle aspira- ● Bilirubinuria is always abnormal in a cat.
tion, biopsy or excision of mass. ● The bilirubin test pad may change color if the
urine is heavily pigmented as with hematuria.
Most common upper urinary tract neoplasms include
lymphoma and carcinoma. Bilirubinuria may occur because of prehepatic, hepatic
● Renomegaly is usually present; lymphoma often or posthepatic causes of excess bilirubin in the plasma.
involves both kidneys. ● Bilirubinemia and bilirubinuria occur when the
● Neoplastic cells may be present on microscopic hepatic capacity to process bilirubin is over-
examination of urine sediment. whelmed by marked hemolysis. Hemolysis is asso-
● Survey abdominal radiography may reveal ciated with anemia that is usually regenerative, and
renomegaly. most commonly caused by Hemobartonellosis or
● Renal ultrasonography may reveal a discreet renal immune-mediated mechanisms.
mass or diffuse hyperechogenicity if lymphoma is ● Bilirubinuria also occurs when the capacity of
involved. the liver to process bilirubin is reduced, causing
● Definitive diagnosis is made by fine-needle aspira- bilirubinemia. There are many causes for hepatic-
tion, biopsy or nephrectomy. related icterus, but hepatic lipidosis, cholangio-