Page 310 - Clinical Small Animal Internal Medicine

278 Section 3 Cardiovascular Disease

result in tamponade. Additional rarely reported causes History and Clinical Signs
VetBooks.ir of pericardial effusion in dogs include renal failure/ Patients can be affected to various degrees, ranging from
uremia, coagulopathy, and migrating foreign bodies
no overt clinical signs to severe compromise. Clinical signs,
including grass awns, porcupine quills, and gun pellets.
when present, are often nonspecific and can include leth-
argy, anorexia, collapse, cough, and vomiting. Respiratory
Cats signs (tachypnea, dyspnea, cough) are common complaints
Heart Failure in cats. Abnormal physical examination findings that are
The most common cause of pericardial effusion in cats, suggestive of pericardial effusion can include muffled or
it can develop with any significant underlying heart distant heart sounds, weak pulses or variation in pulse
disease including hypertrophic cardiomyopathy. The quality with respiration, and tachycardia. Signs of overt
volume of effusion is typically small with heart failure right heart failure (abdominal distension from ascites) and
and resolves with heart failure management. Cats with evidence of increased right heart pressures, including jug-
heart failure‐associated pericardial effusion have a ular venous distension, can also be present.
shorter survival time than cats with pericardial effusion
not caused by heart disease.
Diagnosis
Neoplastic
This is a rare cause of pericardial effusion in the cat. The A complete diagnostic work‐up is recommended to
most common tumors reported in cats with pericardial assess clinical status and create a treatment plan.
effusion are lymphoma, thymoma, mesothelioma, and Evaluation includes but may not be limited to a complete
adenocarcinoma. The clinical effects of cardiac tumors blood count, biochemistries, coagulation testing, urinal-
are related principally to compression or obstruction of ysis, blood pressure, thoracic radiographs, electrocardi-
adjacent cardiac structures, infiltration of the myocar- ography, and echocardiography. In addition, point‐of‐care
dium, and development of pericardial effusion. ultrasound in the emergency setting is helpful for rapidly
detecting pericardial effusion. Infectious disease testing
Infectious may be indicated in endemic areas or if one is suspected.
In the past, infection was considered the most common Additional tests may be indicated depending on clinical
cause of pericardial effusion in the cat related to the status or presenting signs.
historical prevalence of feline infectious peritonitis
( coronavirus). The prevalence of pericardial effusion in Thoracic Radiographs
cats with feline infectious peritonitis (coronavirus) is An enlarged, globoid cardiac silhouette suggests the
9.6–12.8%. presence of pericardial effusion (Figure 28.1c,d). Small‐
volume pericardial effusions may not cause a rounded
Other appearance. Additional findings include dorsal deviation
Additional rarely reported causes of pericardial effu- of the trachea, caudal vena cava distension, and hepato-
sion in cats include renal failure/uremia, trauma, and megaly. Some specific abnormalities indicative of the
coagulopathy. underlying diagnosis include abnormal bulges at the
heart base suggestive of a mass, left atrial enlargement in
degenerative mitral valve disease (Figure 28.1e,f), and
Signalment
pulmonary metastasis. When present, pleural effusion
Dogs often impedes assessment of the cardiac silhouette.
In general, dogs are middle aged to older and large breed Pulmonary edema is uncommon in dogs with pericardial
(golden retriever, German shepherd). Golden retrievers effusion but can be present in cats with heart failure.
are the most overrepresented breed presenting with per-
icardial effusion. They are also the most commonly Echocardiography
reported breed with hemangiosarcoma. Brachycephalic Echocardiography (cardiac ultrasound) provides a non-
breeds are predisposed to heart base tumors (chemodec- invasive means of imaging the heart and surrounding
toma). A young adult dog of any breed would be more structures, and is superior to conventional radiography
likely to have an infectious or idiopathic cause. for identifying pericardial effusion, which appears as a
hypoechoic space surrounding the heart (Figure 28.2).
Cats Additionally, echocardiography can identify the etiology
Irrespective of cause, the most reported breed is domes- of pericardial effusion, such as neoplastic or underlying
tic shorthair although pure breeds can be affected. heart disease. Pericardial effusion provides a source of
Median age at presentation is 6.0 years. ultrasonic contrast that is helpful when attempting to