Module 4: Cardiovascular Pathology - Schreeg (Week 6) Flashcards
Disturbance of Growth:
Uncontrolled and abnormal growth of cells that exhibits invasive behavior
Neoplasia
- Can be primary of metastatic
What does not occur as a ‘response’ to injury, BUT is a morphologic change?
Neoplasia
- Malignant and aggressive neoplasm of endothelial cells that is common in aged large breed dogs
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
What is the most common tumor out there?
Lymphoma
- Malignant neoplasm of lymphocytes that can occur in the heart in any species -> most common in cattle infected with bovine leukosis virus (BLV)
Lymphoma
- RA most common
- arrhythmias, loss of functional myocardial mass
- 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
Chemodectoma
- red mottling mass arising from/attached to the base of the heart
- left side
- can be incidental finding
Cell Death and Associated Lesions:
- Sublethal, reversible cell injury
- No gross lesions, but key histologic changes
Cardiac Myofiber Degeneration
Cell Death and Associated Lesions:
- Lethal, irreversible cell injury
Cardiac Myofiber Necrosis
- Toxins: Ionophores
- Nutritional: Vitamin E/Selenium Deficiency
- Infectious: Blackleg
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
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
Cell death and Associated Lesions:
- Non-specific response to chronic injury
- Collagen replaces or infiltrates between myofibers and/or on endocardial or epicardial surfaces
Cardiac Fibrosis
- Indicates chronicity
Cell death and Associated Lesions:
Gross appearance: Firm foci of tissue pallor
Cardiac Fibrosis
- Jet Lesions = Raised, linear, fibrotic endocardial/endothelial lesions secondary to high-pressure “jets” of blood flow caused by turbulence, regurgitation, etc
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
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
What allows the cardiac muscle cells to contract in a coordinated fashion so that the heart can work as a pump?
Intercalated discs
Intercalated discs are part of the sarcolemma and contain two structures important in cardiac muscle contraction, which are:
Gap junctions and desmosomes
Definition:
Anchor the ends of cardiac muscle fibers together so the cells do not pull apart during individual fiber contraction
Desmosomes
What are the most important component of the tunica intima and form the primary barrier between blood and tissue?
Endothelial cells
Disturbance of Growth
Definition:
Increase in cell size
Hypertrophy
Definition:
Increase in number of cells
Hyperplasis
Definition:
Increase in the number of cells
Hyperplasia
Disturbances of Growth:
The heart has more mass than normal due to an increase in the size of cardiac myofibers
Hypertrophy
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
Concentric
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
Eccentric
Cardiac Hypertrophy:
Diastolic dysfunction = Heart can’t relax
Concentric
Cardiac Hypertrophy:
Systolic dysfunction = Heart can’t contract
Eccentric
Clinical Presentation:
- Old Cats with weight loss, thyroid slip, elevated
- Thyroid adenoma
- Increased metabolic demands of the body contributes to hypertension and concentric hypertrophy
Thyrotoxic Cardiomyopathy
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
Hypertrophic Cardiomyopathy
Clinically Relevant Examples: Eccentric Hypertrophy
- Bi-ventricular eccentric hypertrophy
Canine Dilated Cardiomyopathy
Clinically Relevant Examples: Eccentric Hypertrophy
- Right ventricular eccentric hypertrophy
Boxer Cardiomyopathy
Disturbance of Growth:
Decrease in cardiac size/mass
Atrophy
Disturbance of Growth:
Small size that is present from birth
Hypoplasia
Clinically Relevant Example:
Myofiber atrophy can be seen with any _______________
End-stage cardiomyopathy
(T/F) eccentric hypertrophy and atrophy can be easily differentiated grossly
False, it may be impossible to differentiate grossly
Definition:
Mechanisms involved in the formation of a thrombus in an injured vessel
Thrombosis
Definition:
Coagulation of blood
Clot
Definition:
Coagulation of blood in a vessel lumen
Thrombus
Definition:
A fragment of SOMETHING is lodged in a vessel
Embolism (could be anything)
Definition:
The fragment of a thrombus breaks and gets lodged further down the vessel
Thromboembolism
Definition:
Ischemia and infarction
sequela of thrombosis
Describe the Gross appearance of Thrombosis:
- Motting red-tan
- Dull surface
- Firm texture
- Endothelial adherence
- Feline saddle thrombus
- Pulmonary thromboembolism (PTE)
- Portal thrombosis
- Caval thrombus
These are clinically relevant examples of …
Thrombosis
Definition:
Exudation of blood outside of a vessel due to injured endothelium or alterations in platelets or coagulation factors
Hemorrhage
Describe the Gross features of Hemorrhage:
Red to dark red discoloration or fluid/gelatinous material where it doesn’t belong
Hemorrhage vs. Congestion
Definition:
Engorged but intact vessels
Congestion
Hemorrhage vs. Congestion
Definition:
Blood outside of vessels
Hemorrhage
- 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 …
Endocarditis
List the Gross findings for Valvular Endocarditis:
- Raised
- Roughened
- Friable
- Yellow to tan to red material
(so-called ‘vegetative’ lesions)
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
Traumatic Reticulopericarditis
- AKA “Hardware Disease”
Prevention: Prophylactic ‘placement’ of magnets in the reticulum
What are the gross findings for hardware disease?
- Suppurative pericarditis
- Foul odor
- Acute: Fibrinosuppurative pericarditis (“bread and butter disease”)
- Chronic: Fibrous adhesions (restrictive pericarditis)
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
Vasculitis
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
Equine Verminous Arteritis
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
Heartworm Disease
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
Congestive Heart Failure
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
Left-sided Congestive Heart Failure
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)
Pulmonary edema
Left-sided Congestive Heart Failure
Functional significance of pulmonary edema:
What does fluid in the air spaces lead to?
Impaired oxygen perfusion, tachypnea, dyspnea, and hypoxia
Left-sided Congestive Heart Failure
List examples of common diseases for which left-sided heart failure is a consequence:
- Feline HCM
- Canine mitral valve disease
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
Right-sided Congestive Heart Failure
Passive hepatic congestion:
- Enlarged, dark red liver with rounded margins
Acute passive congestion
Passive hepatic congestion:
- “nutmeg liver” due to centrilobular congestion contrasting with vacuolar change/swelling of portal hepatocytes
Chronic passive congestion
What is the Functional significance of Right-sided congestive heart failure?
Effusiosns can impede lung (pleural) and heart (pericardial) function; significant passive congestion in the liver can lead to centrilobular hepatocyte necrosis
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
Cor Pulmonale
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
Cardiac Tamponade
What is the Function significance of Cardiac Tamponade?
Cardiac compression by fluid in the pericardium -> compression of the right heart -> reduced cardiac output to the lungs, right-sided heart failure -> systemic hypoxia
Definition:
Reduction of blood flow and oxygen to tissue that can result in cellular degeneration or necrosis
Ischemia
Definition:
Tissue necrosis secondary to ischemia
Infarction
List the possible causes for Ischemia and Infarction:
- Thrombosis
- Vasculitis
- Vascular compression from external masses or inflammation
Infarction:
- Red due to a combination of hemorrhage and congestion
Acute infarctions
Infarction:
- Tan due to cell swelling and hemolysis/degradation of RBCs
Subacute infarctions (1-5 days)
Infarction:
- Tan, firm and depressed due to loss of tissue architecture and replacement by fibrosis
Chronic infarctions
Functional significance:
What will infarctions result in?
Coagulative necrosis and loss of functional organ mass
Ischemia and Infarction: Organ Considerations
Brain and nervous tissue will undergo …
Liquefactive necrosis (malacia)
Ischemia and Infarction: Organ Considerations
Liver and lung will undergo …
Infarction RARE due to the dual blood supply
Ischemia and Infarction: Organ Considerations
Myocardial infarction (“heart attack”) is ….
uncommon in domestic animals, but can be associated with atherosclerosis in primates, pigs, and birds
Ischemia and Infarction: Organ Considerations
Chronic renal infarctions are …
COMMON in aged cats: associated with “chronic kidney disease” in this species
Ischemia and Infarction: Organ Considerations
Intestinal infarction is …
the sequela of strangulating lesions (e.g strangulating lipoma, volvulus) and “thromboembolic colic” in horses
Definition:
- Clinicopathologic syndrome in which critical organs are under-perfused with blood
Shock
What is the most common tumor out there?
Lymphoma
(T/F) Neither hypertrophy nor atrophy has the appearance of distinct pale tan nodules in the heart
True
