Lecture 20 9/27/24

Question 1

What are the characteristics of feline idiopathic hypertrophic cardiomyopathy?

Answer 1

-common in all breeds
-most common in young adult males
-sudden death due to arrhythmia is common

Question 2

Which cat breeds have inherited feline idiopathic HCM?

Answer 2

-Maine coons
-ragdoll

Question 3

What are the necropsy findings in cats with feline idiopathic HCM?

Answer 3

-thickened intraventricular septum and left ventricular free wall
-dilated left atrium

Question 4

What are the characteristics of an end-stage HCM heart?

Answer 4

-fibrotic and relatively thin-walled
-will still weigh more than a normal heart

Question 5

What are the characteristics of HCM in canines?

Answer 5

-uncommon
-typically associated with an underlying cause

Question 6

What are the characteristics of feline thyrotoxic cardiomegaly?

Answer 6

-seen in older cats
-associated with thyroid adenomatous hyperplasia/hyperthyroidism
-not the same as HCM which is a primary myocardial disease

Question 7

What are the characteristics of feline endomyocarditis?

Answer 7

-LV endocardial fibrosis complex
-inflammatory stage most often occurs in young cats
-history typically includes a stressful event
-resp. distress is most common presentation

Question 8

What are the necropsy findings in feline endomyocarditis?

Answer 8

-enlarged heart
-possible discoloration of aortic outflow tract
-LV hemorrhage and inflammation in acute cases
-LV endocardial fibrosis in chronic cases

Question 9

Which bacteria is associated with feline endomyocarditis?

Answer 9

Bartonella spp.

Question 10

What are the characteristics of endocardiosis?

Answer 10

-aka myxomatous mitral valve degeneration
-common aging change in dogs
-common cause of CHF in small dogs
-predisposed to chordae tendinae rupture and actue clinical decomp.

Question 11

What is the gross lesion associated with endocardiosis?

Answer 11

smooth white-gray valvular nodules

Question 12

What is the microscopic lesion associated with endocardiosis?

Answer 12

myxomatous nodules expanding valves

Question 13

Which breed is endocardiosis most common in?

Answer 13

Cavalier King Charles spaniels

Question 14

What is endocarditis?

Answer 14

inflammation of the endocardium that is typically bacterial and valvular

Question 15

What are the characteristics of endocarditis in dogs?

Answer 15

-often seen in large breeds older than 5 years
-endocardiosis is NOT a predisposing factor
-left side is most affected

Question 16

Which bacteria are associated with endocarditis in dogs?

Answer 16

-Bartonella; aortic
-Streptococcus; mitral/polyarthritis
-gram neg. bacteria; any valve

Question 17

Where is endocarditis most common in different large animal species?

Answer 17

-horses: left side; aortic > mitral
-ruminants: right side; tricuspid > pulmonic
-camelids: right side; tricuspid > pulmonic

Question 18

What is the gross lesion associated with endocarditis?

Answer 18

rough tan to red material adhered to valves

Question 19

What is the microscopic lesion associated with endocarditis?

Answer 19

fibrin and bacteria

Question 20

What are the consequences of endocarditis?

Answer 20

-56% mortality rate
-valvular insufficiency and CHF
-septic emboli and multi-organ infarcts

Question 21

What are the characteristics of endocardial fibrosis?

Answer 21

-end-stage lesion of feline endomyocarditis
-secondary to chronic turbulence leads to diffuse opacity of endocardium
-associated with jet lesions
-occur in atria above AV valves with endocardiosis

Question 22

What is a jet lesion?

Answer 22

-focal endocardial fibrosis secondary to turbulence
-raised plaque that is often linear

Question 23

What are the characteristics of false tendons/excessive moderator bands?

Answer 23

-web-like network of fibrous strands in LV
-perpendicular to long axis of heart
-not attached to valve leaflets
-most common in cats

Question 24

What are the characteristics of congenital hematomas?

Answer 24

-most common in ruminants
-filled with blood or serum

Question 25

What are the characteristics of CHF?

Answer 25

-get pulmonary congestion and edema
-see liver congestion
-pulmonary hemosiderosis/brown coloring possible, esp. with heartworms
-brown color caused by hemosiderin within alveolar macrophages

Question 26

What are the possible types of edema seen in CHF?

Answer 26

-ascites
-pericardial effusion
-pleural effusion
-dependent subcutaneous edema
-brisket edema

Question 27

What is the pathogenesis of brisket edema?

Answer 27

-hypoxia results in exaggerated hypoxic pulmonary vasoconstriction
-vasoconstriction causes pulmonary hypertension
-hypertension leads to right ventricular hypertrophy and CHF

Question 28

What are the characteristics of “nutmeg liver?”

Answer 28

-chronic passive congestion of liver
-see centrilobular distribution of dilated sinusoids

Question 29

What is the pathogenesis of saddle thromboembolus?

Answer 29

-feline cardiomyopathy leads to turbulence in dilated left atrium
-turbulence results in formation of left atrial thrombus
-thrombus embolizes to aortic bifurcation/trifurcation
-ischemia and necrosis of hind limbs occurs

Question 30

What are the characteristics of dirofilariasis?

Answer 30

-nematodes in pulmonary arteries and right heart
-huge worm load can cause vena caval syndrome
-pulmonary artery endothelium roughens; proliferative endarteritis
-lungs can be brown due to hemosiderosis

Question 31

What are the characteristics of Strongylus vulgaris larval migration in horses?

Answer 31

-thrombosis in cranial mesenteric artery results in ischemia of intestines and colic
-aneurysm occurs due to weakening of vessel wall by larvae and inflammation