Page 265 - Feline Cardiology

272 Section G: Congestive Heart Failure

DIFFERENTIAL DIAGNOSIS sitic lung disease, primary neoplastic disease
(bronchoalveolar carcinoma), metastatic pulmonary
disease, acute respiratory distress syndrome, pulmo-
Key Points nary contusions, or noncardiogenic (neurogenic) pul-
monary edema. An echocardiogram can help to
• The most common causes of pleural effusion aside eliminate heart failure from the differential list of dis-
from heart failure are neoplasia, pyothorax, and feline eases causing pulmonary infiltrates. Echocardiographic
infectious peritonitis. Fluid analysis helps distinguish assessment of a normal left atrial size eliminates car-
pyothorax and feline infectious peritonitis from heart diogenic pulmonary edema from the differential list, in
failure. the absence of an acute precipitating factor such as
• Common differentials for pulmonary infiltrates intravenous fluid administration. Serum cardiac
aside from cardiogenic pulmonary edema include biomarker assay may also be very sensitive and specific
pneumonia, neoplasia, acute respiratory distress
syndrome, inflammatory lung disease, or neurogenic (see Chapter 8).
(noncardiogenic) pulmonary edema.
• Right heart failure, neoplasia, and liver disease are
the most common differential diagnoses of ascites Ascites
Cardiovascular and neoplastic disorders are the most
in cats. Concurrent pleural effusion is almost always
Congestive Heart Failure Pleural Effusion 50% of the cases in a retrospective case series (Wright
common causes of ascites in cats and account for over
present in addition to ascites in cats with right heart
failure.
et al. 1999). Ascites is almost always seen in conjunc-
tion with pleural effusion in cats with congestive heart
failure, and concurrent mild pericardial effusion (not

order of occurrence, the most common to least
Pleural effusion is the abnormal accumulation of fluid
within the pleural space secondary to any of a wide causing cardiac tamponade) is also common (37%). In
common causes of ascites in a case series of 65 cats
variety of pathologic processes, which include increased included congestive heart failure (29%), neoplasia
systemic and pleural capillary hydrostatic pressures (28%), hepatic disease (17%), renal disease (9%), feline
(congestive heart failure), decreased plasma oncotic infectious peritonitis (6%), peritonitis (6%), and
pressure (hypoalbuminemia <1.5 g/dl), increased capil- urinary tract trauma (5%) (Wright et al. 1999).
lary permeability (inflammation, vasculitis), lymphatic Abdominal fluid analysis and cytology may be helpful
obstruction or dysfunction, infectious causes, trauma, in narrowing the differential diagnosis list. Ascites due
coagulopathy, parasitic (heartworm or Aleurostrongylus), to heart failure may be classified as a transudate, modi-
and intrathoracic neoplasia. According to a case series fied transudate (most common), or chylous. Aside from
of 82 cats with pleural effusion, the most common eti- heart failure, the main differentials for a transudate
ologies aside from congestive heart failure (9/82 cats, include portal hypertension or hypoalbuminemia
11%) were pyothorax (18%), mediastinal lymphoma (<1.5 g/dl) secondary to liver failure, protein-losing
(17%), and feline infectious peritonitis (18%) (Davies enteropathy, protein-losing nephropathy, or glomeru-
et al. 1996). Pleural fluid analysis and cytology help lonephropathy. Modified transudate ascitic fluid may
eliminate many of the differentials for congestive heart be consistent with postsinusoidal portal hypertension,
failure (infectious, hemorrhagic, feline infectious peri- liver disease/failure, neoplasia, congestive heart failure,
tonitis), with neoplasia and idiopathic chylous effusion or obstruction of the caudal vena cava (i.e., from a
remaining as the highest differentials. thrombus or invasive adrenal mass). In a study of 45
cats with peritoneal effusion, only ∼7% of ascites was
classified as chylous (Wright et al. 1999). There are
Pulmonary Edema many etiologies that can cause chylous peritoneal effu-
Distinguishing cardiogenic pulmonary edema from sion, including congestive heart failure, neoplasia, peri-
other causes of pulmonary infiltrates can be very chal- tonitis, or trauma (Wright et al. 1999). In summary,
lenging in cats. Unlike dogs, there is no consistent the index of suspicion of congestive heart failure as the
radiographic pattern of pulmonary edema accumula- cause of ascites is greater when there is concurrent
tion in cats with heart failure. The main differentials pleural and/or pericardial effusion. Fluid analysis may
for pulmonary infiltrates aside from heart failure help discriminate between heart failure and the many
include: infectious (bacterial, fungal disease, toxoplas- other etiologies of ascites, with neoplasia and liver
mosis), inflammatory (eosinophilic lung disease), para- failure remaining the highest differentials.