Module 4: Cardiovascular Pathology - Schreeg (Week 6)

Question 1

Disturbance of Growth:
Uncontrolled and abnormal growth of cells that exhibits invasive behavior

Answer 1

Neoplasia
- Can be primary of metastatic

Question 2

What does not occur as a ‘response’ to injury, BUT is a morphologic change?

Answer 2

Neoplasia

Question 3

• Malignant and aggressive neoplasm of endothelial cells that is common in aged large breed dogs

Answer 3

Hemangiosarcoma
- Predilection site: Right atrium/auricle
- Widespread metastasis common: Lungs, spleen, and liver
- rupture of the hemangiosarcomas that can lead to cavity hemorrhage and shock

Question 4

What is the most common tumor out there?

Answer 4

Lymphoma

Question 5

• Malignant neoplasm of lymphocytes that can occur in the heart in any species -> most common in cattle infected with bovine leukosis virus (BLV)

Answer 5

Lymphoma
- RA most common
- arrhythmias, loss of functional myocardial mass

Question 6

• Neoplasm arising from chemoreceptor cells at the base of the aorta (aortic body) -> brachycephalic dogs predisposed
  - often slow-growing but can be malignant with distant metastasis

Answer 6

Chemodectoma
- red mottling mass arising from/attached to the base of the heart
- left side
- can be incidental finding

Question 7

Cell Death and Associated Lesions:
- Sublethal, reversible cell injury
- No gross lesions, but key histologic changes

Answer 7

Cardiac Myofiber Degeneration

Question 8

Cell Death and Associated Lesions:
- Lethal, irreversible cell injury

Answer 8

Cardiac Myofiber Necrosis
- Toxins: Ionophores
- Nutritional: Vitamin E/Selenium Deficiency
- Infectious: Blackleg

Question 9

Cell Death and Associated Lesions: Grass appearance
- Tissue pallor progressing to prominent white-yellow foci that may be firm or mineralized; can have accompanying hemorrhage

Answer 9

Cardiac Myofiber Necrosis
- White muscle disease (young ruminants): Myofiber necrosis due to oxidative damage from Vitamin E/Se deficiency
- Hemorrhage: Mulberry heart Disease (Pigs): Myofiber AND vascular necrosis due to oxidative damage from Vitamin E/Se deficiency
- Acute Hemorrhage: Blackleg = Clostridial Myositis: Myofiber necrosis and hemorrhage due to toxin production by Clostridium chauvoei; minimal inflammation

Question 10

Cell death and Associated Lesions:
- Non-specific response to chronic injury
- Collagen replaces or infiltrates between myofibers and/or on endocardial or epicardial surfaces

Answer 10

Cardiac Fibrosis
- Indicates chronicity

Question 11

Cell death and Associated Lesions:
Gross appearance: Firm foci of tissue pallor

Answer 11

Cardiac Fibrosis
- Jet Lesions = Raised, linear, fibrotic endocardial/endothelial lesions secondary to high-pressure “jets” of blood flow caused by turbulence, regurgitation, etc

Question 12

Cell death and Associated Lesions:
- Deposition of calcium salts into tissue
- Two flavors
- Metastatic: Secondary to systemic calcium and phosphorus imbalance
- Dystrophic: Secondary to local tissue necrosis and calcium release

Answer 12

Cardiac Mineralization
- Gross feature: White to tan foci that are HARD and Chalky
- Dystrophic mineralization should be associated with another underlying cardiac lesion (i.e. necrosis)
- Metastatic mineralization will NOT be associated with another cardiac lesion but will be associated with other lesions of Ca/P imbalance

Question 13

What allows the cardiac muscle cells to contract in a coordinated fashion so that the heart can work as a pump?

Answer 13

Intercalated discs

Question 14

Intercalated discs are part of the sarcolemma and contain two structures important in cardiac muscle contraction, which are:

Answer 14

Gap junctions and desmosomes

Question 15

Definition:
Anchor the ends of cardiac muscle fibers together so the cells do not pull apart during individual fiber contraction

Answer 15

Desmosomes

Question 16

What are the most important component of the tunica intima and form the primary barrier between blood and tissue?

Answer 16

Endothelial cells

Question 17

Disturbance of Growth
Definition:
Increase in cell size

Answer 17

Hypertrophy

Question 18

Definition:
Increase in number of cells

Answer 18

Hyperplasis

Question 19

Definition:
Increase in the number of cells

Answer 19

Hyperplasia

Question 20

Disturbances of Growth:
The heart has more mass than normal due to an increase in the size of cardiac myofibers

Answer 20

Hypertrophy

Question 21

Disturbance of Growth: Cardiac Hypertrophy
- Response to increased afterload (increased pressure)
- Heart must ‘beef up’ to ‘push against’ increased pressure
- Myofibers have sarcomeres added in parallel = flatter myofibers
- Heart is thicker, chambers narrow

Answer 21

Concentric

Question 22

Disturbance of Growth: Cardiac Hypertrophy
- Response to increased preload (increase volume)
- Heart must ‘stretch’ to ‘accommodate’ increased volume
- Myofibers have sarcomeres added in series = longer myofibers
- Heart is thinner, chambers dilated

Answer 22

Eccentric

Question 23

Cardiac Hypertrophy:
Diastolic dysfunction = Heart can’t relax

Answer 23

Concentric

Question 24

Cardiac Hypertrophy:
Systolic dysfunction = Heart can’t contract

Answer 24

Eccentric

Question 25

Clinical Presentation: - *Old* Cats with weight loss, thyroid slip, elevated - Thyroid adenoma - Increased metabolic demands of the body contributes to *hypertension and concentric hypertrophy*

Answer 25

Thyrotoxic Cardiomyopathy

Question 26

Clinical presentation: - *Young to middle-aged* cats, possibly purebred (Maine Coon, Sphynx, Ragdoll) - Stasis of blood in *left atrium* can result in *thrombus* formation that can detach and become lodged in the distal aorta -> saddle thrombus

Answer 26

Hypertrophic Cardiomyopathy

Question 27

Clinically Relevant Examples: Eccentric Hypertrophy - Bi-ventricular eccentric hypertrophy

Answer 27

Canine Dilated Cardiomyopathy

Question 28

Clinically Relevant Examples: Eccentric Hypertrophy - *Right ventricular* eccentric hypertrophy

Answer 28

Boxer Cardiomyopathy

Question 29

Disturbance of Growth: Decrease in cardiac size/mass

Answer 29

Atrophy

Question 30

Disturbance of Growth: Small size that is present from birth

Answer 30

Hypoplasia

Question 31

Clinically Relevant Example: Myofiber atrophy can be seen with *any* _______________

Answer 31

End-stage cardiomyopathy

Question 32

(T/F) eccentric hypertrophy and atrophy can be easily differentiated grossly

Answer 32

False, it may be impossible to differentiate grossly

Question 33

Definition: Mechanisms involved in the formation of a thrombus in an injured vessel

Answer 33

Thrombosis

Question 34

Definition: Coagulation of blood

Answer 34

Clot

Question 35

Definition: Coagulation of blood in a vessel lumen

Answer 35

Thrombus

Question 36

Definition: A fragment of SOMETHING is lodged in a vessel

Answer 36

Embolism (could be anything)

Question 37

Definition: The fragment of a thrombus breaks and gets lodged further down the vessel

Answer 37

Thromboembolism

Question 38

Definition: Ischemia and infarction

Answer 38

sequela of thrombosis

Question 39

Describe the Gross appearance of Thrombosis:

Answer 39

- Motting red-tan - Dull surface - Firm texture - Endothelial adherence

Question 40

- Feline saddle thrombus - Pulmonary thromboembolism (PTE) - Portal thrombosis - Caval thrombus These are clinically relevant examples of ...

Answer 40

Thrombosis

Question 41

Definition: Exudation of blood outside of a vessel due to injured endothelium or alterations in platelets or coagulation factors

Answer 41

Hemorrhage

Question 42

Describe the Gross features of Hemorrhage:

Answer 42

Red to dark red discoloration or fluid/gelatinous material where it doesn't belong

Question 43

Hemorrhage vs. Congestion Definition: Engorged but intact vessels

Answer 43

Congestion

Question 44

Hemorrhage vs. Congestion Definition: Blood outside of vessels

Answer 44

Hemorrhage

Question 45

- Can affect the heart wall (mural) or more commonly valves (valvular) - Almost always caused by bacterial agents -- suppurative inflammation - Aortic and mitral valves most commonly affected except in cattle (tricuspid) This is describing ...

Answer 45

Endocarditis

Question 46

List the Gross findings for Valvular Endocarditis:

Answer 46

- Raised - Roughened - Friable - Yellow to tan to red material (so-called 'vegetative' lesions)

Question 47

Pericarditis: Clinically relevant example - Primary traumatic puncture by sharp foreign bodies from the reticulum of cattle through the diaphragm and into the pericardial sac with secondary bacterial colonization/infection of the wound tract

Answer 47

Traumatic Reticulopericarditis - AKA "Hardware Disease" Prevention: Prophylactic 'placement' of magnets in the reticulum

Question 48

What are the gross findings for hardware disease?

Answer 48

- Suppurative pericarditis - Foul odor - Acute: Fibrinosuppurative pericarditis ("bread and butter disease") - Chronic: Fibrous adhesions (restrictive pericarditis)

Question 49

Definition: - Presence of inflammatory cells infiltrating and disrupting the wall of the vessel - Most often is a result of either infectious or immune-mediated diseases

Answer 49

Vasculitis

Question 50

Vasculitis: Clinically Relevant Examples - Cranial mesenteric arteritis (large vessel) in horses due to migration of L4 larvae of Strongylus vulgaris (large strongyle) - Gross findings: Thickened, roughened, fibrotic, tortuous vessel walls +/- aneurysms, occasional ruptures, formation of luminal thrombi

Answer 50

Equine Verminous Arteritis

Question 51

Vasculitis: Clinically Relevant Examples - Worms cause physical irritation, proliferation, and fibrosis of pulmonary vessels - Proliferative arteritis -- thickened with markedly narrow lumen - Pulmonary hypertension, pulmonary thromboembolism

Answer 51

Heartworm Disease

Question 52

Definition: - Process of 'backing up' of blood within the cardiovascular system and accumulation of extravascular/cavitary fluid (edema and effusions) due to failure of appropriate cardiac output - Sequela of MANY heart diseases - Can be divided into right and left-sided heart failure

Answer 52

Congestive Heart Failure

Question 53

Definition: - Failure of the left heart to appropriately pump blood out to the body -> backup of fluid into the lungs - Gross features: Pulmonary edema, Cavitary (pleural, pericardial, peritoneal) effusions in CATS - In other species, USUALLY indicates right-sided heart failure

Answer 53

Left-sided Congestive Heart Failure

Question 54

Definition: Wet, heavy lungs that exude abundant clear to red-tinged watery fluid on cut surface; can be brown-tinged with chronicity (macrophages eat RBCs and break down pigments)

Answer 54

Pulmonary edema

Question 55

Left-sided Congestive Heart Failure Functional significance of pulmonary edema: What does fluid in the air spaces lead to?

Answer 55

Impaired oxygen perfusion, tachypnea, dyspnea, and hypoxia

Question 56

Left-sided Congestive Heart Failure List examples of common diseases for which left-sided heart failure is a consequence:

Answer 56

- Feline HCM - Canine mitral valve disease

Question 57

Definition: - Failure of the right heart to appropriately pump blood to the lungs -> backup of blood and fluid in the rest of the body - Gross findings: - Abdominal organ congestion, including passive hepatic congestion - Cavitary effusions in animals other than cats - Subcutaneous or dependent edema

Answer 57

Right-sided Congestive Heart Failure

Question 58

Passive hepatic congestion: - Enlarged, dark red liver with rounded margins

Answer 58

Acute passive congestion

Question 59

Passive hepatic congestion: - "nutmeg liver" due to centrilobular congestion contrasting with vacuolar change/swelling of portal hepatocytes

Answer 59

Chronic passive congestion

Question 60

What is the Functional significance of Right-sided congestive heart failure?

Answer 60

Effusiosns can impede lung (pleural) and heart (pericardial) function; significant passive congestion in the liver can lead to centrilobular hepatocyte necrosis

Question 61

Unique conditions leading to Right-sided Congestive Heart Failure Pathogenesis: Interstitial lung diseases -> hypoxia and pulmonary hypertension -> right-sided heart failure - Long-term interstitial pneumonia - "High altitude disease" of cattle

Answer 61

Cor Pulmonale

Question 62

Unique conditions leading to Right-sided Congestive Heart Failure - Compression of the heart due to severe pericardial effusion - Hemopericardium most common: RA hemangiosarcoma rupture - Gross findings: Fluid markedly distends pericardial sac; cavitary effusion or abdominal organ congestion due to right-sided heart failure

Answer 62

Cardiac Tamponade

Question 63

What is the Function significance of Cardiac Tamponade?

Answer 63

Cardiac compression by fluid in the pericardium -> compression of the right heart -> reduced cardiac output to the lungs, right-sided heart failure -> systemic hypoxia

Question 64

Definition: Reduction of blood flow and oxygen to tissue that can result in cellular degeneration or necrosis

Answer 64

Ischemia

Question 65

Definition: Tissue necrosis secondary to ischemia

Answer 65

Infarction

Question 66

List the possible causes for Ischemia and Infarction:

Answer 66

- Thrombosis - Vasculitis - Vascular compression from external masses or inflammation

Question 67

Infarction: - Red due to a combination of hemorrhage and congestion

Answer 67

Acute infarctions

Question 68

Infarction: - Tan due to cell swelling and hemolysis/degradation of RBCs

Answer 68

Subacute infarctions (1-5 days)

Question 69

Infarction: - Tan, firm and depressed due to loss of tissue architecture and replacement by fibrosis

Answer 69

Chronic infarctions

Question 70

Functional significance: What will infarctions result in?

Answer 70

Coagulative necrosis and loss of functional organ mass

Question 71

Ischemia and Infarction: Organ Considerations Brain and nervous tissue will undergo ...

Answer 71

Liquefactive necrosis (malacia)

Question 72

Ischemia and Infarction: Organ Considerations Liver and lung will undergo ...

Answer 72

Infarction RARE due to the dual blood supply

Question 73

Ischemia and Infarction: Organ Considerations Myocardial infarction ("heart attack") is ....

Answer 73

uncommon in domestic animals, but can be associated with atherosclerosis in primates, pigs, and birds

Question 74

Ischemia and Infarction: Organ Considerations Chronic renal infarctions are ...

Answer 74

COMMON in aged cats: associated with "chronic kidney disease" in this species

Question 75

Ischemia and Infarction: Organ Considerations Intestinal infarction is ...

Answer 75

the sequela of strangulating lesions (e.g strangulating lipoma, volvulus) and "thromboembolic colic" in horses

Question 76

Definition: - Clinicopathologic syndrome in which critical organs are under-perfused with blood

Answer 76

Shock

Question 77

What is the most common tumor out there?

Answer 77

Lymphoma

Question 78

(T/F) Neither hypertrophy nor atrophy has the appearance of distinct *pale tan nodules in the heart*

Answer 78

True