Chapter 54 - Pericardial effusion

Question 1

What breeds are commonly affected by pericardial effusion? Most affected breed?

Answer 1

Golden retrievers.

German shepherd dogs, Labrador retrievers, and St Bernards are also commonly affected.

Question 2

Is it common to find pericardial effusion in cats?

Answer 2

No.
Only 1–2% of all cats admitted to referral hospitals have pericardial effusion. PE in the cat is often an incidental finding discovered during diagnostic workup of other diseases, frequently secondary to congestive heart failure

Question 3

Differentials for hemorrhagic pericardial effusions in dogs?

Answer 3

1) Neoplasia
i) HSA, 61% of all canine PE cases)
ii) Heart base tumors
iii) Ectopic thyroid tumors

2) Idiopathic pericarditis
3) Coagulopathy, trauma, and left atrial rupture in small-breed dogs with severe endocardiosis

Question 4

Where does cardiac HSA typically grow from?

Answer 4

The wall of the right atrium or right auricle.

Question 5

At the time of diagnosis, cardiac HSA has usually metastasized to other organs. What are these organs?

Answer 5

Most commonly metastasize to the lungs, liver, or spleen.

Concurrent splenic, pulmonary or hepatic tumors may be identified in only about 25% of all cases.

Question 6

What are cardiac neoplasias that can cause hemorrhagic pericardial effusions in dogs?

Answer 6

1. cardiac HSA (two-thirds of all cardiac tumors)
2. Heart base tumors - including chemodectomas (aortic body tumors)
3. Ectopic thyroid tumors.
   Heart base tumors and ectopic thyroid tumors are still relatively uncommon, with an incidence that is 10-fold lower than cardiac HSA

Question 7

Breeds predisposed to heart base tumors?

Answer 7

Boxers, English bulldogs and Boston terriers

Question 8

It is often difficult to diagnose cardiac mesothelioma.

WHY?

Answer 8

Mesotheliomas are often difficult to diagnose without histopathology because they may not form discrete masses and cytological analysis of effusions often fails to differentiate neoplastic cells from reactive mesothelial cells.

Question 9

Causes of septic pericarditis

Answer 9

foreign body migration
penetrating trauma
various bacterial, fungal, and protozoal infections

Question 10

Pathophysiology of cardiac tamponade?

Answer 10

Compression of the heart, especially of the right ventricle due to a thinner wall → interventricular septum shifts towards the left ventricle chamber → ↓ ventricular diastolic filling → decreased stroke volume → ↓ cardiac output → systemic venous congestion.

Question 11

Why cardiac tamponade occurs less commonly with chronic pericardial effusion?

Answer 11

With chronic accumulation of PE, renin-angiotensin-aldosterone system increases fluid retention and offsets the rise in intrapericardial pressure by increasing preload. The pericardial space will also gradually stretch and expand. Both factors allow for large volumes of PE to develop before the onset of cardiac tamponade

Question 12

Echocardiographic evidence of cardiac tamponade?

Answer 12

Diastolic collapse of the right atrial free wall.

Severe cases may also demonstrate collapse of the right ventricle