Page 283 - Problem-Based Feline Medicine

16 – THE CAT WITH ACUTE DEPRESSION, ANOREXIA OR DEHYDRATION 275

● CT-scanning has low sensitivity. The diagnostic util-
severe in acute renal failure and will not normalize
ity of magnetic resonance imaging is not known.
with rehydration. Acute renal failure may be a com-
Some cases have had no changes.
plication of acute pancreatitis.
Thoracic radiographs should be obtained in dyspneic
Liver disease.
cats to rule out pleural effusion, which may be caused
● Elevations in liver enzymes, bilirubin and choles-
by pancreatitis. Dyspnea may rarely be due to pul-
terol may characterize both pancreatitis and liver
monary thromboembolism.
diseases. Furthermore, hepatic lipidosis and cholan-
Definitive ante-mortem diagnosis requires biopsy giohepatitis are common concurrent disorders with
obtained by exploratory laparotomy or laparoscopy. acute pancreatitis. It is often difficult to establish if
The pancreas may appear grossly normal (or show only one disorder preceded the other, and to establish if
nodular hyperplasia in the older cat). one is more responsible for clinical signs. Moderate
to marked liver enzyme elevations are suggestive of
A cat with pancreatitis may be a poor anesthetic risk.
primary hepatic disease, and a disproportionate ele-
Acute exacerbation of pancreatitis occasionally occurs
vation of ALP compared to ALT and GGT is sug-
following biopsy.
gestive of hepatic lipidosis. Elevations in serum bile
Inflammation may be irregularly distributed in dogs acids in the absence of cholestasis confirm the pres-
and multiple biopsies are recommended; the situation ence of hepatocellular dysfunction. Elevated
may be the same in cats. plasma ammonia levels are diagnostic for hepatic
encephalopathy. Marked coagulation abnormalities
Ultrasound-guided fine-needle aspiration may be
are suggestive of liver disease. Abdominal ultra-
used to biopsy pancreatic masses. Amylase and lipase
sound examination of cats with liver disease is rec-
should be measured in cystic fluid – levels above
ommended in an effort to detect pancreatitis. If
serum levels support a diagnosis of pseudocyst; lev-
laparotomy is performed to obtain a liver biopsy,
els equivalent to serum levels do not rule out a
then a pancreatic biopsy should also be obtained,
pseudocyst.
and vice versa.
Diabetic ketoacidosis (DKA).
Differential diagnosis
● Confirmation of DKA requires demonstration of
Acute anemia. hyperglycemia, ketonuria or ketonemia, and
● Some cats with acute pancreatitis will have pale acidosis. DKA may be confused with pancreatitis
mucous membranes from shock. Routine haema- because urine test strips measure oxaloacetate or
tology will confirm severe anemia. Anemia is usu- acetone, which may be produced in minimal quan-
ally only mild in pancreatitis. tities by cats, and cats with pancreatitis may be
hyperglycemic. Several drops of hydrogen perox-
Urethral obstruction.
ide may be added to the urine sample in an effort
● A painful turgid bladder is palpable. Rarely the
to convert β-hydroxybutyrate to oxaloacetate to
obstruction has spontaneously resolved by the time
increase the concentration of oxaloacetate in
the cat is presented for examination. In the latter
urine. Alternatively, β-hydroxybutyrate may be
case, diagnosis is established by history, prepucial
measured in serum using a point-of-care test, or
crystal deposits, urinalysis and azotemia.
the urine test strip may be used to detect oxaloac-
Acute renal failure. etate in heparinized plasma. Using a standard
● Both acute renal failure and pancreatitis may urine test strip, a negative plasma test rules out
cause depression, anorexia, dehydration, vomiting, ketosis, and a positive urine test rules in ketosis,
azotemia and reduced urine production. In acute in cats. It should be remembered that acute pan-
renal failure urine will be isosthenuric to minimally creatitis and DKA may occur concurrently. Acute
concentrated, while in acute pancreatitis urine pancreatitis, DKA and hypoglycemia should
should be well-concentrated, unless there is pre- always be considered in an acutely depressed dia-
existing chronic renal failure. Azotemia is more betic cat.