Page 458 - Problem-Based Feline Medicine

450 PART 7 SICK CAT WITH SPECIFIC SIGNS

of inflammatory proteins and neutrophils from Bile in the peritoneal cavity results from traumatic
the vasculitis. injury to the gall bladder or bile ducts. It is rare in cats.
– In septic peritonitis the fluid is a septic exudate The presence of bile may be associated with septic or
containing bacteria and increased levels of pro- non-septic peritonitis, with increases in bacteria and/or
tein, neutrophils and bacteria. protein and neutrophils accordingly.
– In pancreatitis the fluid is a modified transudate
Urine in the peritoneal cavity usually results from trau-
to non-septic exudate, depending on the increase
matic injury to the urinary bladder. It is uncommon in
in protein and cells.
cats. Rarely direct effusion of urine may occur with
– Ascites may be associated with a decreased
severe cystitis. The presence of urine may be associated
effective plasma volume, which promotes salt
with septic or non-septic peritonitis, with increases in
and water retention by the renin-angiotensin-
bacteria and/or protein and neutrophils accordingly.
aldosterone system, antidiuretic hormone, and
Rupture of the bladder may also cause abdominal hem-
the sympathetic nervous system, thereby helping
orrhage.
to maintain the ascitic state. (Water retention
may result in hyponatremia. Hyperkalemia may Fat accumulates because of overeating and underactiv-
also result from a decreased effective plasma ity. Fat accumulates within the abdomen as well as
volume and other mechanisms in cats with within the abdominal subcutaneous tissue, especially of
ascites. The combination of hyponatremia and the caudal ventral abdomen.
hyperkalemia mimics hypoadrenocorticism.)
Food may cause increased distention of the stomach
Chyle in the peritoneal cavity is an uncommon non- and small intestine after a large meal. This is a physio-
specific finding indicating that lymphatic rupture has logic cause of organomegaly.
occurred. Chylous effusion may occur with any of the
Feces may cause increased distention of the large intes-
basic mechanisms that promote peritoneal fluid pro-
tine after a large meal. This is a physiologic cause of
duction except for hypoalbuminemia. Most cases are
organomegaly. More often, increased accumulation of
caused by neoplasia, and fewer are caused by inflam-
feces in the large intestine is a sign of constipation.
mation, right heart failure and liver disease. Other
Severe constipation (obstipation, megacolon) may
causes are rare in cats, including primary abdominal
result in marked abdominal distention.
lymphangiectasia and traumatic rupture of a major
lymphatic vessel. Flatus (gastrointestinal air) is not physiologically com-
mon in cats. Flatus may develop secondary to aeropha-
Blood in the peritoneal cavity results from injury to
gia in dyspneic cats and as a sign of primary intestinal
blood vessels, spontaneous or traumatic rupture of
disorders. Gastric dilation-volvulus is rare. Abdominal
abnormal blood-filled spaces, or a coagulopathy.
distention may also develop from pneumoperitoneum.
Hemoperitoneum is not as common in cats as dogs,
Sources of air include gastric perforation, gastrointesti-
because abdominal trauma does not commonly cause
nal rupture, extension of air from the thoracic cavity,
severe abdominal hemorrhage in cats, and heman-
penetrating abdominal wounds and intra-abdominal
giosarcoma is rare. Other causes of hemoperitoneum in
gas-forming bacteria.
the dog such as anticoagulant rodenticide poisoning,
perforated gastrointestinal ulcers, and splenic torsions, Fetuses are a cause of physiologic organomegaly.
are also uncommon in cats. Clinical signs due to acute
Formidable organomegaly usually results from
anemia and local effects of hemorrhage vary with the
markedly distended hollow organs (bladder, intestinal
severity of bleeding. Signs of acute hypovolemia, e.g.
tract, uterus) or neoplasia. Granulomatous inflammation,
weakness, lethargy, hypothermia, pale mucus mem-
cyst and pseudocyst formation is less common. Rare
branes, tachycardia and weak pulses, occur with a
causes include heterotopic ossification. Acute inflamma-
smaller volume of blood loss than do abdominal dis-
tion of an organ usually causes minimal to moderate
tention. In most cases of hemoperitoneum in cats,
organomegaly and does not cause abdominal distention.
abdominal distention is not noted. In converse, cats
with abdominal distention due to acute blood loss will Feeble abdominal musculature is caused by hyper-
have signs of hypovolemia. adrenocorticism.