Page 199 - Feline Cardiology

202 Section E: Other Forms of Structural Heart Disease

DIFFERENTIAL DIAGNOSIS
Echocardiographically, circumscribed masses may be
abscesses, granulomas, cysts, or neoplasms. Chemo-
dectomas typically are mixed echogenicity masses that
may best be identified between the aorta and either
atrium, or adjacent to the cranial vena cava in 1 case.
Myocardial infiltration may be focal (Shinohara et al.
2005) or diffuse (Brummer and Moïse 1989; Liu et al.
1989). Diffuse infiltration may be mistaken for
hypertrophic cardiomyopathy if attention is not paid
to the variable echogenicity that is usually present and
the hypokinesis (reduced motion) of the infiltrated
Misc. Heart Diseases DIAGNOSTIC TESTING
myocardium.

Cardiac neoplasia in cats arises in three clinical
contexts:

1. A patient shows clinical signs (e.g., respiratory prob-
lems) that ultimately are found to be caused by the
effects of the neoplasm
Figure 16.1. Pluck from a cat with lymphoma. Discrete, pale, 2. A patient with cancer that shows no overt signs of
raised lesions are present on the epicardial surface (arrows), con- cardiac dysfunction, but diagnostic testing reveals
sistent with lymphoma. Photo courtesy of Dr. Kristin MacDonald.
cardiac abnormalities consistent with cardiac
neoplasia
3. A patient in which the finding is made incidentally at
from ascites. In cats, by contrast, this expression of necropsy
cardiac neoplasia appears to be uncommon. Rather, the
most widely reported chief complaints are tachypnea For the first and second scenarios, a diagnosis is pursued
and/or dyspnea that most commonly has been noted by beginning with the least invasive, most rewarding tests
owners for a few days to one week, or rarely more. first. Depending on results, further testing often pro-
Concurrently, such systemic signs as anorexia and leth- ceeds through minimally invasive (e.g., needle-sampling
argy occur, and these typically are noted for a few days and cytologic examination) and can extend to tissue-
before the onset of severe respiratory signs prompts the based analysis (biopsy) with confirmatory intent; cura-
owners to seek veterinary attention. tive intent is rarely feasible due to extensive infiltration
A number of cases of cardiac tumors are diagnosed or adhesion. The extent to which a confirmatory diag-
incidentally at necropsy, suggesting that the cardiac neo- nosis is sought depends on the following features of the
plasia produces no characteristic clinical signs or causes case: patient’s stability and capacity to tolerate testing;
signs that are mild and that pass unnoticed. opportunity to confirm the diagnosis by lesser invasive
means, including test repetition (e.g., a second centesis
PHYSICAL EXAMINATION later); client wishes and abilities, both financial and
emotional; and to some degree expected prognosis,
Cats with cardiac tumors may present with few or no
signs referable to the lesion, and the diagnosis is made although speculating on prognosis can be dangerous.
when the tumor is found incidentally at necropsy.
Conversely, severe respiratory signs are present in some Initial Tests
cats in whom marked pleural effusion is present. Abnormalities of routine laboratory tests (complete
Information regarding the presence of general demeanor, blood count, serum biochemical profile, urinalysis) are
body condition, heart sounds, arrhythmia, pulse quality, not usually noted in cats with cardiac tumors. Serologic
signs of right-sided heart failure, and many other impor- testing for FeLV is variable: 3 of 5 reported cats with
tant physical findings is generally lacking from the cardiac lymphoma had a negative FeLV test result and 2
literature. had a positive result.