Cardiovascular Flashcards
Veins always …
(a) carry blue blood
(b) carry deoxygenated blood
(c) travel towards the heart
(c) travel towards the heart
Arteries always …
(a) carry red blood
(b) carry oxygenated blood
(c) travel away from the heart
(c) travel away from the heart
Name the major blood vessels that enter the left atrium.
Pulmonary veins
Name the major blood vessels that enter the right atrium.
Cranial vena cava AND caudal vena cava
Name the major blood vessel that leaves the left ventricle.
Aorta
Name the major blood vessel that leaves the right ventricle.
Pulmonary trunk
Name the heart valve at the outflow of the right ventricle.
Pulmonic valve
Name the heart valve at the outflow of the right atrium.
Right atrioventricular valve (“tricuspid” valve)
Name the heart valve at the outflow of the left ventricle.
Aortic valve
Name the heart valve at the outflow of the left atrium.
Left atrioventricular valve (“mitral” valve)
Which is the higher pressure system: the pulmonary or systemic circulation?
Systemic circulation is higher pressure
Which is the lower pressure system: the pulmonary or systemic circulation?
Pulmonary circulation is lower pressure
Which side of the heart (right or left) propels blood through the pulmonary circulation?
Right
Which side of the heart (right or left) propels blood through the systemic circulation?
Left
There are six BASIC pathophysiologic mechanisms of cardiac dysfunction. What are they?
(1) Pump failure: Weak contractility and emptying of chambers, impaired filling of chambers.
(2) Obstruction to forward blood flow: Valvular stenosis, vascular narrowing, systemic or pulmonary hypertension.
(3) Regurgitant blood flow: Volume overload of chamber behind failing affected valve.
(4) Shunted blood flows from congenital defects: Septal defects in heart, shunts between blood vessels.
(5) Rupture of the heart or a major vessel: Cardiac tamponade, massive internal hemorrhage.
(6) Cardiac conduction disorders (arrhythmias): Failure of synchronized cardiac contraction.
There are six short- and long-term compensations that help maintain cardiac output for a while in the face of cardiac disease. What are they?
(1) Increased heart rate
(2) Increased peripheral resistance
(3) Increased blood volume
(4) Redistribution of blood flow
(5) Cardiac dilation
(6) Myocardial hypertrophy
Is dysfunction of the mitral valve more likely to cause left-sided heart failure or right-sided heart failure?
Left-sided heart failure
Is dysfunction of the aortic valve more likely to cause left-sided heart failure or right-sided heart failure?
Left-sided heart failure
Is dysfunction of the tricuspid valve more likely to cause left-sided heart failure or right-sided heart failure?
Right-sided heart failure
Is dysfunction of the pulmonic valve more likely to cause left-sided heart failure or right-sided heart failure?
Right-sided heart failure
The decreased blood flow to peripheral tissues caused by heart failure is called …
Forward failure
The accumulation or backing up of blood “upstream” from a failing heart chamber is called …
Backward failure
What does the term “forward failure” mean as it pertains to the systemic effects of heart failure?
The decreased blood flow to peripheral tissues caused by heart failure.
What does the term “backward failure” mean as it pertains to the systemic effects of heart failure?
The accumulation or backing up of blood “upstream” from a failing heart chamber
Explain the pathogenesis whereby renal HYPOTENSION (not hypoxia) caused by a failing heart can worsen heart disease.
Failing heart -> Reduced flow to peripheral tissues -> RENAL HYPOTENSION ->
Renin release from juxtaglomerular apparatus (JGA) -> Aldosterone release from adrenal cortex -> Sodium & water retention -> Increased plasma volume -> Increased workload for already failing heart -> WORSENING HEART DISEASE
Explain the pathogenesis whereby renal HYPOXIA (not hypotension) caused by a failing heart can worsen heart disease.
Failing heart -> Reduced flow to peripheral tissues -> RENAL HYPOXIA -> Erythropoietin release from kidney -> Increased erythropoiesis in bone marrow -> Polycythemia -> Increased blood viscosity -> Increased workload for already failing heart -> WORSENING HEART DISEASE
List four gross NON-CARDIAC lesions that may be caused by accumulation of blood behind a failing chamber (backward failure).
(1) Subcutaneous edema; (2) Ascites; (3) Pulmonary edema; (4) Hepatic congestion and hepatomegaly
What is the characteristic non-cardiac lesion seen in ACUTE left-sided heart failure?
Acute pulmonary congestion & edema
Pulmonary lesions are typically associated with which type of heart failure: left-sided or right-sided?
Left-sided
What are three characteristic non-cardiac lesions seen in CHRONIC left-sided heart failure?
(1) Chronic pulmonary edema; (2) Pulmonary fibrosis; (3) Pulmonary hemosiderosis (lungs appear tan-brown due to the presence of “heart failure cells” in alveoli. These are alveolar macrophages containing recycled iron pigments from red blood cells that have been “squeezed” into the alveolar lumen and phagocytosed.)
What is the characteristic non-cardiac lesion seen in ACUTE right-sided heart failure?
Acute passive congestion in liver (-> hepatomegaly)
What is the characteristic non-cardiac lesion seen in CHRONIC right-sided heart failure?
Chronic passive congestion of the liver (-> enhanced reticular pattern that, in this case, can actually be called “nutmeg liver”)
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Match each of the following animals to the most common type of edema shown in heart failure (e.g., a-1):
(a) Cat; (b) Dog; (c) Horse; (d) Ruminant
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(a) Cat - (2) Hydrothorax
(b) Dog - (1) Ascites
(c) Horse - (3) Subcutaneous edema
(d) Ruminant - (3) Subcutaneous edema
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Which of the following is most typical in a CAT with heart failure?
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(2) Hydrothorax
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Which of the following is most typical in a DOG with heart failure?
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(1) Ascites
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Which of the following is most typical in a HORSE with heart failure?
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(3) Subcutaneous edema
Right-sided heart failure often causes severe edema. Different domestic species manifest edema in different anatomic locations. Which of the following is most typical in a COW with heart failure?
(1) Ascites; (2) Hydrothorax; (3) Subcutaneous edema
(3) Subcutaneous edema
What is the term for accumulation of serous fluid (i.e., a transudate, not blood or exudate) in the pericardial space?
Hydropericardium
What does the term hydropericardium mean?
Accumulation of serous fluid (i.e., a transudate, not blood or exudate) in the pericardial space
What are three possible reasons for the development of hydrothorax, and what, briefly, is the pathogenesis of each?
(1) Hypoproteinemia (-> decreased colloid oncotic pressure): e.g., liver failure, protein-losing nephropathy, protein-losing enteropathy
(2) Heart failure (-> increased hydrostatic pressure); may also see ascites or hydrothorax
(3) Widespread vascular injury (-> leakage of plasma and plasma proteins); certain infectious diseases such as heartwater in ruminants, African horse sickness, African swine fever, bovine ephemeral fever … [many are exotic]
Hydropericardium and hydrothorax are synonyms. True or false?
False. Fluid accumulates in the pericardial cavity in hydropericardium but in the pleural cavities in hydrothorax.
What does the term hemopericardium mean?
The accumulation of whole blood in the pericardial cavity
What is the term for the accumulation of whole blood in the pericardial cavity?
Hemopericardium
Which is more likely to be rapidly fatal: hemopericardium or hydropericardium? And why?
Hemopericardium is more likely to be rapidly fatal as blood accumulation is typically sudden and caused by a bleeding vessel or chamber. The pericardium cannot distend, resulting in the heart being compressed by accumulated blood within the fibrous pericardial sac and failing acutely. This is called cardiac tamponade.
PLEASE NOTE THAT AT THIS POINT ONLY HALF THE ANSWER REQUIRED HAS BEEN PROVIDED. THE REMAINDER IS BELOW. PLEASE FINISH YOUR ANSWERS IN EXAMS.
In contrast, fluid accumulates slowly and at low pressure in hydropericardium, allowing the pericardium time to expand to some degree. This avoids compression of the heart.
By far the most common cause for hemopericardium in dogs is “leaking” cardiac hemangiosarcomas. What are three other, less common causes?
(1) Idiopathic; (2) Spontaneous atrial rupture; (3) Blunt force thoracic trauma (e.g., by car); (4) Intracardiac injections; (5) Other cardiac neoplasm (e.g., aortic body tumor AKA chemodectoma)
What is the most common cause for hemopericardium in dogs?
“Leaking” cardiac hemangiosarcomas. Typically these are located on the right auricle.
What is the most common cause for hemopericardium in horses?
Spontaneous aortic rupture. [NOT hemangiosarcoma; you’re thinking of dogs.]
You are performing a necropsy on a horse. As you peel the pericardial sac off the heart you are reminded of the appearance of soft butter when two slices of bread are peeled apart. What are you dealing with? And what is the most likely cause?
Fibrinous or fibrinosuppurative pericarditis; either is fine. [NOT fibrous pericarditis, hemopericardium, hydropericardium, or intrapericardial injection of spreadable dairy products.] In horses this is typically caused by bacterial septicemia, e.g., Streptococcus equi
You are performing a necropsy on a pig. As you peel the pericardial sac off the heart you are reminded of the appearance of soft butter when two slices of bread are peeled apart. What are you dealing with? And what is the most likely cause?
Fibrinous or fibrinosuppurative pericarditis; either is fine. [NOT fibrous pericarditis, hemopericardium, hydropericardium, or intrapericardial injection of spreadable dairy products.] In pigs this is typically caused by bacterial septicemia, e.g., Haemophilus parasuis
You are performing a necropsy on a cow. As you peel the pericardial sac off the heart you are reminded of the appearance of soft butter when two slices of bread are peeled apart. What are you dealing with? And what is the most likely cause?
Fibrinous or fibrinosuppurative pericarditis; either is fine. [NOT fibrous pericarditis, hemopericardium, hydropericardium, or intrapericardial injection of spreadable dairy products.] In cattle this is typically caused by bacterial septicemia, e.g., Histophilus somni. It can also be caused by “hardware disease” AKA traumatic reticulopericarditis, where the pericardium is penetrated by a nail or wire from the gut.
What is indicated by serous atrophy of epicardial fat?
A negative plane of energy. e.g., anorexia, starvation, cachexia, GIT parasitism etc.
You are performing a necropsy on a bison. You notice that the epicardial fat is grey to clear and gelatinous. What is the term for this and what does it suggest?
Serous atrophy of fat. It suggests a negative plane of energy. e.g., anorexia, starvation, cachexia, GIT parasitism etc.
You are performing a necropsy on a bison. You notice that the epicardial fat is white to yellow and abundant. What is the term for this and what does it suggest?
Normal epicardial fat. It suggests that the animal was maintaining its energy requirements and was not anorexic, starved, cachexic etc.
What is the most common pericardial neoplasm?
Mesothelioma (a malignant tumor of mesothelial cells)
Mesothelioma is the most common pericardial neoplasm. Is it benign or malignant?
Malignant, despite its -oma name. There is no benign form of mesothelioma.
Mesothelioma may arise within the pericardial cavity from pericardial mesothelial cells. Where else in the body can mesothelioma arise?
The pleural cavities and the peritoneal cavity.
Mesothelial cells are the flattened cells that line serous body cavities and produce a small amount of lubricating fluid. What are the names of the (a) benign and (b) malignant neoplasms that arise from mesothelial cells?
(a) Trick question. There is no such thing as a benign mesothelial tumor. (b) Mesothelioma is the malignant neoplasm arising from mesothelial cells.
Which vessels are connected in the congenital cardiac abnormality “PDA” (patent ductus arteriosus)
The aorta and pulmonary trunk
Name two normal fetal cardiac shunts AND their names postnatally.
(1) Foramen ovale -> fossa ovalis
(2) Ductus arteriosus -> ligamentum arteriosum
In which domestic species is the congenital cardiac abnormality “PDA” (patent ductus arteriosus) most commonly seen?
Dogs
In which direction (left to right or right to left) does blood flow in a patent ductus arteriosus? And why?
Left to right (postnally). This is because the pressure in the aorta exceeds the pressure in the pulmonary trunk. Blood takes the “path of least resistance” and a proportion of aortic blood is sent via the PDA into the pulmonary trunk. This causes overperfusion of the lungs.
Which organs “suffer the most” in an animal with a patent ductus arteriosus?
The lungs. A proportion of aortic blood is sent via the PDA into the pulmonary trunk. This causes overperfusion of the lungs.
In which direction (left to right or right to left) does blood flow in a patent foramen ovale? And why?
Left to right (postnatally). This is because the pressure in the left atrium exceeds the pressure in the right atrium.
In which direction (left to right or right to left) does blood flow in an atrial septal defect? And why?
Left to right (postnatally). This is because the pressure in the left atrium exceeds the pressure in the right atrium.
You are performing a necropsy on a dog and find that the right ventricle has a markedly thickened wall. In addition, its outflow valve is malformed and has a band of fibrous tissue immediately proximal to it. What are you most likely seeing?
Pulmonic stenosis. This is a congenital malformation of the pulmonic valve. The resulting narrowing (stenosis) causes concentric hypertrophy of the right ventricular wall.
Aside from the valvular malformation itself, what is the most prominent lesion you would expect in the heart of a dog with congenital pulmonic stenosis?
Right ventricular concentric hypertrophy
You are performing a necropsy on a dog and find that the left ventricle has a markedly thickened wall. In addition, its outflow valve has a band of fibrous tissue immediately proximal to it. What are you most likely seeing?
Subaortic stenosis. This is a congenital malformation where a ring of fibrous tissue encircles the left ventricular outflow tract beneath the aortic valve. The resulting narrowing (stenosis) causes concentric hypertrophy of the left ventricular wall.
Aside from the valvular malformation itself, what is the most prominent lesion you would expect in the heart of a dog with congenital subaortic stenosis?
Left ventricular concentric hypertrophy
Describe the (a) appearance and (b) function of an AV valve affected by congenital atrioventricular valve dysplasia.
(a) AV valve leaflets and chordae tendineae are short and thickened; (b) Incompetent valve function -> regurgitation of blood [-> heart failure]
You are performing a necropsy on a calf and find a dark purple 7 mm diameter spherical cyst on the free edge of the left AV valve. What is this and what is its significance?
A valvular hematocyst. These are bulging blood-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.
You are performing a necropsy on a calf and find a clear 7 mm diameter spherical cyst on the free edge of the left AV valve. What is this and what is its significance?
A valvular lymphocyst. These are bulging lymph-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.
What are valvular hematocysts, where are they most commonly found, and in which domestic species?
These are bulging blood-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.
Which canine congenital cardiac developmental anomaly is associated with esophageal obstruction?
Persistent right aortic arch
What is the most common vascular ring anomaly in dogs?
Persistent right aortic arch
Which canine congenital cardiac developmental disorder is most likely in a stunted young dog with frequent regurgitation of food?
Persistent right aortic arch
From which aortic arch should the aorta develop normally?
Left fourth
In cases of persistent right aortic arch, from which aortic arch did the aorta develop?
Right fourth
What clinical sign is noticed first by owners of dogs suffering from persistent right aortic arch (PRAA)? What are three other, less spectacular but still important clinical effects or lesions of PRAA?
Frequent regurgitation of food is the most obvious clinical sign.
(1) Cranial megaesophagus; (2) Aspiration pneumonia; (3) Stunting
In the condition persistent right aortic arch, what specific structure causes esophageal entrapment and stenosis?
The ligamentum arteriosum
Describe the pathogenesis of the condition persistent right aortic arch, from causal developmental abnormality to production of the most common clinical signs and lesions.
Aorta develops abnormally from the right 4th aortic arch instead of the left 4th aortic arch -> this creates a vascular ring with the ligamentum arteriosum (which developed normally from the left 6th aortic arch) -> the esophagus passes through and is entrapped by this vascular ring -> esophageal narrowing at this point -> frequent regurgitation of food [+/- cranial megaesophagus, aspiration pneumonia and stunting]
What is ectopia cordis?
A developmental anomaly where the heart develops at an abnormal site outside of the thoracic cavity. The most common ectopic location is subcutaneously in the caudoventral neck, just cranial to the thoracic inlet.
What is the term for the developmental anomaly where the heart develops at an abnormal site outside of the thoracic cavity?
Ectopia cordis. The most common ectopic location is subcutaneously in the caudoventral neck, just cranial to the thoracic inlet.
What are three specialized histologic features of cardiac myocytes that set them apart from other types of muscle cells?
(1) They branch; (2) They have intercalated discs; (3) Some of them are specialized (e.g., Purkinje cells) to form a conducting system
Do cardiac myocytes undergo (a) hyperplasia or (b) hypertrophy in response to increased workload?
(b) Hypertrophy
Describe the appearance of a transversely sectioned heart with biventricular concentric hypertrophy.
The ventricular myocardium is marked thickened (hypertrophied) and the volume of the ventricular chamber lumen on each side is reduced and sometimes slit-like.
Describe the appearance of a transversely sectioned heart with biventricular eccentric hypertrophy.
The ventricular myocardium is thickened (hypertrophied) but this is overshadowed by marked enlargement (dilation) of the ventricular chamber lumen on each side. Because of this chamber dilation the myocardium may appear relatively thinned, but it is still hypertrophied.
Fill in the blank: ventricular concentric hypertrophy is a result of __________ overload.
Pressure
Fill in the blank: ventricular eccentric hypertrophy is a result of __________ overload.
Volume
Fill in the blank: cardiac ventricular pressure overload results in __________ hypertrophy.
Concentric
Fill in the blank: cardiac ventricular volume overload results in __________ hypertrophy.
Eccentric
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in aortic valvular stenosis? And why?
Concentric and left. Aortic stenosis causes PRESSURE overload in the left ventricle. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in pulmonic valvular stenosis? And why?
Concentric and right. Pulmonic stenosis causes PRESSURE overload in the right ventricle. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in chronic systemic hypertension? And why?
Concentric and left. Systemic hypertension causes PRESSURE overload in the left side of the heart. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in chronic pulmonary hypertension? And why?
Concentric and right. Pulmonary hypertension causes PRESSURE overload in the right side of the heart. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in hyperthyroidism in cats?
Concentric and biventricular.
Which type of ventricular hypertrophy (concentric or eccentric) would be expected in aortic or pulmonic valvular insufficiency (“leakiness”)? And why?
Eccentric. Valvular insufficiency (“leakiness”) results in backflow of blood into an already full heart chamber. This is VOLUME overload. Volume overload leads to chamber dilation, or ECCENTRIC hypertrophy. (In contrast, concentric hypertrophy is associated with PRESSURE overload).
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in a ventricular septal defect? And why?
Eccentric and right. Ventricular septal defects result in blood crossing into an already full right ventricle. Blood moves left to right rather than right to left because the pressure in the left ventricle exceeds pressure in the right ventricle. This is VOLUME overload. Volume overload leads to chamber dilation, or ECCENTRIC hypertrophy. (In contrast, concentric hypertrophy is associated with PRESSURE overload).
Chronic pulmonary hypertension may result in right ventricular concentric hypertrophy. What is a fairly common disease that causes this in (a) dogs, (b) cattle and (c) horses?
(a) Dogs: “Heartworm disease” (dirofilariasis), where nematodes live in the pulmonary arteries, pulmonary trunk and right atrium.
(b) Cattle: “Brisket disease” (high altitude disease), where cattle above 7000 feet develop right-sided heart failure.
(c) Horses: “Heaves” (chronic alveolar emphysema), which is an asthma-like condition.
What does the term cor pulmonale mean?
Right-sided heart failure caused by chronic pulmonary hypertension
What is the term for right-sided heart failure caused by chronic pulmonary hypertension?
Cor pulmonale
Name the three most common types of cardiomyopathy seen in domestic animals.
(1) Hypertrophic cardiomyopathy (HCM); (2) Dilated cardiomyopathy (DCM); (3) Restrictive cardiomyopathy
In which domestic animal species is hypertrophic cardiomyopathy most common?
Cats (»> dogs)
What is the typical (a) signalment and (b) clinical presentation for a cat with hypertrophic cardiomyopathy?
(a) Young, adult male. Possibly Maine Coon breed; (b) sudden death or congestive heart failure
Describe the gross appearance of the heart of a cat that died from hypertrophic cardiomyopathy.
Marked concentric hypertrophy of left ventricular wall and interventricular septum -> severe reduction of ventricular lumen
What is a common and frequently fatal NON-cardiac complication of hypertrophic cardiomyopathy in cats?
Secondary caudal abdominal aortic thromboembolism (“saddle thrombus”) in ~20% of cases
In which two domestic animal species is dilated cardiomyopathy most common?
Dogs and cats
Which dog breeds are particularly predisposed to development of dilated cardiomyopathy?
Large breeds: Doberman pinschers especially predisposed. Also Irish wolfhounds, St. Bernards, great Danes etc. although any breed can be affected.
Is canine dilated cardiomyopathy more common in females or in males?
Males > females
Feline dilated cardiomyopathy may be associated with which nutritional deficiency?
Taurine deficiency. Supplementation can reverse clinical signs.
Which feline cardiomyopathy is more common in YOUNGER cats: dilated or hypertrophic?
Hypertrophic cardiomyopathy
Which feline cardiomyopathy is more common in OLDER cats: dilated or hypertrophic?
Dilated cardiomyopathy
Is feline dilated cardiomyopathy more common in females or in males?
Males > females
Describe the gross appearance of the heart of a dog that died from dilated cardiomyopathy. Try to name three lesions, not just the single obvious one.
Rounded heart with biventricular dilation. Markedly dilated cardiac chambers; these make the walls appear relatively thin in comparison but it is important to remember that they are still hypertrophic. Diffuse endocardial fibrosis -> thick, white lining in chambers
You are performing a necropsy on a dog that died from heart failure. You note: (a) a rounded heart with biventricular dilation, (b) markedly dilated cardiac chambers, and (c) diffuse endocardial fibrosis resulting in a thick, white lining in all chambers. What is the most likely diagnosis?
Dilated cardiomyopathy
You are performing a necropsy on a cat that died from heart failure. You note marked concentric hypertrophy of the left ventricular wall and interventricular septum that results in severe reduction of the left ventricular lumen. What is the most likely diagnosis?
Hypertrophic cardiomyopathy
Describe the pathogenesis of feline restrictive cardiomyopathy.
Severe endocardial fibrosis (possibly caused by end stage endomyocarditis) -> impaired diastolic relaxation -> reduced ventricular filling (decreased preload) -> decreased cardiac output [->] heart failure
Which is the least common form of cardiomyopathy in domestic animals: dilated, hypertrophic or restrictive?
Restrictive
In which domestic animal species is restrictive cardiomyopathy most common?
Cats
Canine dilated cardiomyopathy may be associated with which type of diet?
Grain-free diets
Grain-free diets may be associated with (a) which disease in (b) which domestic species?
(a) Dilated cardiomyopathy in (b) dogs
Taurine-deficient diets are associated with (a) which disease in (b) which domestic species?
(a) Dilated cardiomyopathy in (b) cats
Which (a) endocrine disease in (b) which domestic species may cause cardiac lesions resembling those of hypertrophic cardiomyopathy?
(a) Hyperthyroidism in (b) cats
Hyperthyroidism in cats may cause cardiac enlargement resembling hypertrophic cardiomyopathy. Explain why this cardiac enlargement is NOT classified as cardiomyopathy.
Cardiomegaly seen in feline hyperthyroidism is due to enhanced production of myocardial contractile proteins under the influence of increased concentration of circulating thyroid hormones. This is reversible if thryoid hormone levels are returned to normal. It is NOT a primary disease of the myocardium; it has an extra-cardiac cause. On the other hand, HCM IS a primary myocardial disease and is not reversible.
Name two diseases of cats that can predispose to FATE (feline aortic thromboembolism or “saddle thrombus”).
(1) Hypertrophic cardiomyopathy and (2) hyperthyroidism
Both feline hypertrophic cardiomyopathy and hyperthyroidism cause cardiac changes predisposing to turbulence and the formation of thrombi within the heart. What is a common sequela of this thrombosis?
FATE (feline aortic thromboembolism or “saddle thrombus”)
Deficiency of which substance is the most common cause of nutritional myocardial necrosis in calves and lambs? And what is the lay term for this disease?
Vitamin E or selenium. “White muscle disease.”
Deficiency of which substance is the most common cause of nutritional myocardial necrosis in pigs? And what is the lay term for this disease?
Vitamin E or selenium. “Mulberry heart disease.”
Why are the lesions of “white muscle disease” in neonatal calves and lambs most commonly detected in the heart and tongue?
These are the hardest working muscles in a neonate and so are the first to show degenerative myonecrosis caused by vitamin E or selenium deficiency.
Where are two good locations to look for the lesions of “white muscle disease” in neonatal calves and lambs? And why?
The heart and tongue. These are the hardest working muscles in a neonate and so are the first to show degenerative myonecrosis caused by vitamin E or selenium deficiency.
Describe the characteristic gross cardiac lesions of nutritional myocardial necrosis in neonatal calves and lambs.
On section the ventricular myocardium has areas of pallor (fibrosis) or pallor, dryness and grittiness (dystrophic mineralization). The ventricular papillary muscles and ventricular subendocardial (i.e., “inner”) myocardium are typically the hardest hit.
Ionophores are potential cardiotoxins, yet are routinely added to animal feed. Why are they added to feed for (a) cattle and (b) poultry?
Ionophores are used as feed additives to: (a) increase feed efficiency and weight gain in cattle, and (b) control coccidiosis in poultry.
Ionophores such as monensin are potential cardiotoxins, yet are routinely added to animal feed. Which domestic animal species is most sensitive to the cardiotoxic effects of ionophores?
Horses.
You are performing a necropsy on a horse that died acutely of heart failure. You note large areas of pallor and mottling in the ventricular myocardium. Which toxin is most likely responsible for this? And how would the horse have gained access?
An ionophore such as monensin should be high in your differential list. Ionophores are extremely toxic to horses, even at low doses. Horses typically gain access through access to ruminant feed (grain bin or feeding trough raids), through horse feed accidentally mixed with ruminant feed, or through horse feed contaminated with ionophores in a mill producing poultry, cattle, and horse feeds.
Which is the most common route of infection for bacterial myocarditis?
Hematogenous
The most common route of infection for bacterial myocarditis is via hematogenous spread. What are the two most common sources for this?
(1) Systemic bacteremia showering myocardium; (2)
Vegetations on heart valves, where bacterial thromboemboli shower the myocardium via the coronary arteries
Bacterial vegetations on heart valves may shower the myocardium, leading to bacterial myocarditis. Outline the route taken by showered bacteria that cause this.
Vegetation on LEFT-sided heart valve (aortic or mitral/LAV) -> left heart chambers -> aorta -> coronary arteries -> seed myocardium -> myocarditis
Which bacterial species (also causing thrombotic meningoencephalitis) commonly causes myocarditis in cattle?
Histophilus somni
Describe the characteristic gross appearance of cardiac lesions of histophilosis in cattle.
Dry, pale areas of necrosis in the ventricular myocardium. Lesions are often found in the longitudinally sectioned ventricular papillary muscle. This is a characteristic location in the heart for histophilosis lesions. [Remember the “boxing glove” cut.]
Which bacterial species (more commonly causing necrohemorrhagic myositis of skeletal muscle or “blackleg”) sometimes causes myocarditis in cattle?
Clostridium chauvoei [please pay attention to spelling]
Describe the characteristic gross appearance of cardiac lesions caused by Clostridium chauvoei in cattle.
Severe necrohemorrhagic myocarditis, possibly with areas of crepitus caused by gas bubble formation.
Explain the pathogenesis whereby a dental cleaning procedure in a cat may lead to severe heart disease.
Dental procedure -> gingival trauma -> gingival bacteria released to circulation -> bacteremia -> formation of bacterial vegetations on heart valves or (less commonly) showering of myocardium via coronary arteries -> heart disease
Explain the pathogenesis whereby a subcutaneous abscess in a cow may lead to severe heart disease.
Abscess -> invasion into tissues -> bacteria released to circulation -> bacteremia -> formation of bacterial vegetations on heart valves or (less commonly) showering of myocardium via coronary arteries -> heart disease
Explain the pathogenesis whereby a hepatic abscess in a cow may lead to severe heart disease.
Hepatic abscess -> invasion into blood vessels walls -> bacteria released to circulation -> bacteremia -> formation of bacterial vegetations on heart valves or (less commonly) showering of myocardium via coronary arteries -> heart disease
Which virus is a relatively common cause of myocarditis in very young puppies?
Canine parvovirus
You are performing a necropsy on a young puppy that died unexpectedly from heart failure. The heart is pale and flaccid and you note several extensive coalescing areas of pallor in the ventricular myocardium. What is the most likely diagnosis?
Canine parvoviral myocarditis
Describe the cardiac lesions in a young puppy that died unexpectedly from heart failure caused by canine parvoviral myocarditis.
The heart is pale and flaccid and the ventricular myocardium contains extensive coalescing areas of pallor.
Which parvoviral syndrome is more common in young dogs aged ~6-20 weeks: (a) profuse hemorrhagic diarrhea or (b) sudden unexpected death from heart failure?
(a) Profuse hemorrhagic diarrhea (i.e., parvoviral hemorrhagic enteritis). Canine parvovirus infects rapidly dividing cells, which in dogs of this age are primarily the epithelial lining cells of the small intestine (enterocytes). By this age cardiac myocytes are no longer dividing and so are resistant to CPV infection.
Which parvoviral syndrome is more common in young puppies aged <4 weeks: (a) profuse hemorrhagic diarrhea or (b) sudden unexpected death from heart failure?
(b) Sudden unexpected death from heart failure (i.e., parvoviral myocarditis). Canine parvovirus infects rapidly dividing cells, which in neonatal puppies up to ~ 15days old includes cardiac myocytes. After this age cardiac myocytes are no longer dividing and so are resistant to CPV infection.
What are three reasons why cardiac endocardial and epicardial hemorrhage could be present at necropsy?
(1) Septicemias, especially those with endotoxins; this is a true lesion; (2) Electrocution or anoxia; this is a true lesion; (3) Agonal change at death; this is a non-significant lesion, which should be ignored
What gross cardiac lesion may be produced by all three of the following conditions: (1) septicemias, especially those with endotoxins; (2) electrocution and anoxia; (3) agonal change at death?
Endocardial and epicardial hemorrhage. Remember that the endocardial and epicardial hemorrhage caused as an agonal change at death is a non-significant lesion, which should be ignored.
What are three possible broad causes of endocardial mineralization?
(1) Excess vitamin D intake: calcinogenic plants in grazing animals or rodenticide toxicity in dogs; (2) Granulomatous disease: Johne’s disease in ruminants; (3) Hypercalcemia of malignancy (i.e., metastatic calcification)
You are performing a necropsy on a horse and notice roughened, firm, gritty plaques on the ventricular and atrial endocardium and along the tunica intima of great vessels. What are some of your potential diagnoses?
This is endocardial mineralization. In horses the potential diagnoses include: (1) excess vitamin D intake from grazing on calcinogenic plants such as Solanum species; (2) metastatic calification caused by hypercalcemia of malignancy.
You are performing a necropsy on a dog and notice roughened, firm, gritty plaques on the ventricular and atrial endocardium and along the tunica intima of great vessels. What are some of your potential diagnoses?
This is endocardial mineralization. In dogs the potential diagnoses include: (1) excess vitamin D from rodenticide toxicity; (2) metastatic calcification caused by hypercalcemia of malignancy.
You are performing a necropsy on a cow and notice roughened, firm, gritty plaques on the ventricular and atrial endocardium and along the tunica intima of great vessels. What are some of your potential diagnoses?
This is endocardial mineralization. In cattle the potential diagnoses include: (1) excess vitamin D intake from grazing on calcinogenic plants such as Solanum species; (2) granulomatous disease such as Johne’s disease; (3) metastatic calcification caused by hypercalcemia of malignancy.
What are three possible broad causes of endocardial fibrosis?
(1) “Jet lesions” due to turbulent blood flow caused by incompetent valves; (2) Chronic cardiac dilation, such as seen with dilated cardiomyopathy; (3) Secondary to healed endocardial ulceration, usually due to uremia.
You are performing a necropsy on a dog and notice roughened, firm, fibrous “streaks” on the left atrial endocardium. What is the most likely diagnosis for this and what is the pathogenesis?
These are “jet lesions”, where an incompetent (leaking) left AV valve has resulted in a jet of blood passing backwards from the left ventricle into the left atrium with each heart beat. This causes turbulence of blood within the left atrium and trauma to the endocardium. Chronically this results in endocardial proliferation and fibrosis, manifesting as streaks, wrinkles and roughening.
You are performing a necropsy on a dog and notice roughened, firm, fibrous “streaks” on the right atrial endocardium. What is the most likely diagnosis for this and what is the pathogenesis?
These are “jet lesions”, where an incompetent (leaking) right AV valve has resulted in a jet of blood passing backwards from the right ventricle into the right atrium with each heart beat. This causes turbulence of blood within the right atrium and trauma to the endocardium. Chronically this results in endocardial proliferation and fibrosis, manifesting as streaks, wrinkles and roughening.
Explain the difference between endocardiosis and endocarditis.
Endocardiosis is caused by degeneration of collagen in atrioventricular valves. In endocardiosis: the cusps of the atrioventricular valves are shortened, nodular, and SMOOTH.
Endocarditis is caused by bacterial colonization of valve cusps, predisposed to by bacteremias and turbulent blood flow. In endocarditis affected valve cusps have large, friable, grey-yellow masses or “vegetations” that, chronically, may become wart-like. Their ROUGH surfaces are distinct from the smooth surfaces of valves with endocardiosis.
Which domestic animal species is most predisposed to development of myxomatous valvular degeneration (endocardiosis)?
Dogs
Myxomatous valvular degeneration is the same as … [choose one]:
(a) Endocardiosis
(b) Endocarditis
(a) Endocardiosis
Myxomatous valvular degeneration (endocardiosis) is the most common cause of congestive heart failure in dogs. True or false?
True. Small and medium breeds, especially cavalier King Charles spaniels, are predisposed.
Myxomatous valvular degeneration (endocardiosis) is the most common cause of congestive heart failure in cattle. True or false?
False. Myxomatous valvular degeneration (endocardiosis) is the most common cause of congestive heart failure in DOGS.
Myxomatous valvular degeneration (endocardiosis) is the most common cause of congestive heart failure in cats. True or false?
False. Myxomatous valvular degeneration (endocardiosis) is the most common cause of congestive heart failure in DOGS.
Dilated cardiomyopathy is the most common cause of congestive heart failure in dogs. True or false?
False. Myxomatous valvular degeneration (endocardiosis) is the most common cause of congestive heart failure in dogs.
Do you think endocardiosis is the same as endocarditis?
No
Which types or breeds of dog are predisposed to myxomatous valvular degeneration (endocardiosis)?
Small and medium breeds, especially cavalier King Charles spaniels
Describe the gross appearance of a canine heart valve affected by myxomatous valvular degeneration (endocardiosis).
The cusps of the atrioventricular valves are shortened, nodular, and smooth. The smoothness distinguishes this disease from the roughed valves seen in endocarditis.
Which canine heart valve is most commonly affected by myxomatous valvular degeneration (endocardiosis)?
The left atrioventricular valve. Left AV (mitral) valve [66% of cases] > Right AV (tricuspid) valve [33% of case]»_space;> Aortic or pulmonic valves [rare]
Which heart valves (atrioventricular, pulmonic, or aortic) are most commonly affected by myxomatous valvular degeneration (endocardiosis)?
Atrioventricular valves. Left AV (mitral) valve [66% of cases] > Right AV (tricuspid) valve [33% of case]»_space;> Aortic or pulmonic valves [rare]
Canine myxomatous valvular degeneration (endocardiosis) leads to which type of cardiac hypertrophy: concentric or eccentric? And why?
Eccentric hypertrophy. This type of hypertrophy results from VOLUME overload, as is seen when valves are incompetent and allow blood to move backwards as well as forwards.
Canine myxomatous valvular degeneration (endocardiosis) could be expected to have associated atrial jet lesions. True or false? Please explain / justify your answer.
True. Affected valves are incompetent (leaky), resulting in a jet of blood passing backwards from the ventricle into the atrium with each heart beat. This causes turbulence of blood within the atrium and trauma to the endocardium. Chronically this results in endocardial proliferation and fibrosis, manifesting as streaks, wrinkles and roughening or “jet lesions.”
Canine myxomatous valvular degeneration (endocardiosis) could be expected to have associated ventricular jet lesions. True or false? Please explain / justify your answer.
False. Affected valves are incompetent (leaky), resulting in a jet of blood passing backwards from the ventricle into the atrium with each heart beat. This causes turbulence of blood within the ATRIUM (not ventricle) and trauma to the ATRIAL endocardium. Chronically this results in endocardial proliferation and fibrosis, manifesting as streaks, wrinkles and roughening or “jet lesions.” These are found in the atrium, not the ventricle.
Canine myxomatous valvular degeneration (endocardiosis) could be expected to have associated atrial dilation. True or false? Please explain / justify your answer.
True. Affected valves are incompetent (leaky), resulting in a jet of blood passing backwards from the ventricle into the atrium with each heart beat. This causes eccentric dilation of the atrium through volume overload.
Explain the key gross difference between lesions of valvular endocardiosis and valvular endocarditis.
Endocardiosis: the cusps of the atrioventricular valves are shortened, nodular, and SMOOTH.
PLEASE NOTE THAT AT THIS POINT ONLY HALF THE ANSWER REQUIRED HAS BEEN PROVIDED. THE REMAINDER IS BELOW. PLEASE REMEMBER TO FINISH YOUR ANSWERS IN EXAMS.
Endocarditis: affected valve cusps have large, friable, grey-yellow masses or “vegetations” that, chronically, may become wart-like. Their ROUGH surfaces are distinct from the smooth surfaces of valves with endocardiosis.
Explain the key gross difference between the cause of valvular endocardiosis versus the cause of valvular endocarditis.
Endocardiosis is caused by degeneration of collagen in atrioventricular valves.
Endocarditis is caused by bacterial colonization of valve cusps, predisposed to by bacteremias and turbulent blood flow.
Canine myxomatous valvular degeneration (endocardiosis) most commonly affects the … [choose one]:
(a) aortic and pulmonic valves
(b) atrioventricular valves
(c) left-sided heart valves
(d) right-sided heart valves
(b) atrioventricular valves
Vegetative valvular endocarditis most commonly affects the … [choose one]:
(a) aortic and pulmonic valves
(b) atrioventricular valves
(c) left-sided heart valves
(d) right-sided heart valves
(c) left-sided heart valves: mitral and aortic
You are performing a necropsy on a horse that died of heart failure. You note that (a) several of the chordae tendineae of the left AV valve are broken and have swollen and hemorrhagic tips, and (b) the endocardial and epicardial surfaces have scattered areas of hemorrhage. What is the significance of lesions (a) and (b)?
(a) These are ruptured chordae tendineae, which are very significant and are likely responsible for this horses heart failure and death.
(b) These are agonal hemorrhages that commonly occur as an animal dies; they are non-significant lesions, which should be ignored (after ruling out significant causes such as septicemia or electrocution).
In which domestic animal species is heart failure caused by ruptured chordae tendineae most common?
Horses
Sometimes during necropsy examination of the heart the chordae tendineae are inadvertently cut by 4th year rotation students (never by pathologists). Why would you not misdiagnose these as ruptured chordae tendineae?
Real ruptured chordae tendineae have swollen, rounded and sometimes hemorrhagic tips. Chordae tendineae that were cut after death have sharp (not rounded) cut surfaces, a normal diameter (no swelling) and no hemorrhage. These are the same principles that apply to determining if any organ was cut before or after death.
What is the most common primary neoplasm of the heart in dogs?
Hemangiosarcoma
In which domestic species is hemagiosarcoma the most common primary neoplasm?
Dog
What is the precise predilection site for development of cardiac hemangiosarcoma in dogs?
The right auricle or atrium
What’s the term for a BENIGN tumor arising from the cells of the myocardium?
Cardiac rhabdomyoma (Note that the term rhabdomyoma means a benign tumor of ANY striated muscle. It is not particular to the heart, and could also apply to any skeletal muscle in the body. Hence the “cardiac” part of cardiac rhabdomyoma.)
What is a cardiac rhabdomyoma?
A BENIGN tumor arising from the striated muscle cells of the myocardium.
What s the term for a MALIGNANT tumor arising from the cells of the myocardium?
Cardiac rhabdomyosarcoma (Note that the term rhabdomyosarcoma means a malignant tumor of ANY striated muscle. It is not particular to the heart, and could also apply to any skeletal muscle in the body. Hence the “cardiac” part of cardiac rhabdomyosarcoma.)
What is a cardiac rhabdomyosarcoma?
A MALIGNANT tumor arising from the striated muscle cells of the myocardium.
What is a chemodectoma?
A neoplasm of the aortic body. The aortic body is one of several small clusters of peripheral chemoreceptors, baroreceptors, and supporting cells located along the aortic arch.
What is another name for an aortic body tumor?
A chemodectoma. The aortic body is one of several small clusters of peripheral chemoreceptors, baroreceptors, and supporting cells located along the aortic arch.
A chemodectoma is a neoplasm of the aortic body. What, and where, is the “aortic body”?
The aortic body is one of several small clusters of peripheral chemoreceptors, baroreceptors, and supporting cells located along the aortic arch.
What are the two most common metastatic tumors of the canine heart?
Hemangiosarcoma and lymphoma
What does the term vasculitis mean?
Inflammation of a blood vessel of any type (arterial or venous system)
What is the general term for inflammation of a blood vessel?
Vasculitis
What is the key difference between a vasculitis and a blood vessel that is full of, and surrounded by, inflammatory cells?
When tissues are inflamed white blood cells arrive via, and then exit and surround, the blood vessels supplying that site. This is NOT a vasculitis. This is just inflammation. To count as vasculitis, the white blood cells must target and damage the wall of the vessel itself.
Which is true:
(a) vasculitis has a narrow range of causes and all are infectious
(b) vasculitis has a broad variety of infectious, non-infectious and idiopathic causes
(b) vasculitis has a broad variety of infectious, non-infectious and idiopathic causes
What is the key lesion resulting from vasculitis?
Hemorrhage
The key lesion of vasculitis is widespread hemorrhage, which may be subdivided based on size. What are the dimensions of (a) ecchymotic, (b) petechial and (c) suffusive hemorrhage?
(a) ecchymotic means 2-10 mm diameter; (b) petechial means 1-2 mm diameter; (c) suffusive means extensive or diffuse
Name two vessel-based sequelae of vasculitis other than hemorrhage.
- Thrombosis (which may lead to thromboembolism, infarction and ischemia)
- DIC (disseminated intravascular coagulation)
What is the term for arterial loss of elasticity and luminal narrowing resulting from proliferative and degenerative (rather than inflammatory) changes of the arterial wall?
Arteriosclerosis?
What is the meaning of the term arteriosclerosis?
Arterial loss of elasticity and luminal narrowing resulting from proliferative and degenerative (rather than inflammatory) changes of the arterial wall
Arteriosclerosis is a common, age-related change most commonly seen in which domestic species?
Dogs
True or false? Arteriosclerosis is a common, cause of myocardial infarction in dogs.
False. Arteriosclerosis is common in dogs (most commonly in the abdominal aorta) but rarely causes clinical signs.
What is the term for lesions of arteriosclerosis in which degenerative fatty changes also occur?
Atherosclerosis
Which is true:
(a) Atherosclerosis is a form of arteriosclerosis
(b) Arteriosclerosis is a form of atherosclerosis
(a) Atherosclerosis is a form of arteriosclerosis. ARTERIOsclerosis is arterial loss of elasticity and luminal narrowing resulting from proliferative and degenerative (rather than inflammatory) changes of the arterial wall. If this degeneration also involves the formation of fatty plaques then this is ATHEROsclerosis.
Which is/are true:
(a) In domestic animals, arteriosclerosis is common, but of little clinical importance, and atherosclerosis is rare
(b) In domestic animals, atherosclerosis is common, but of little clinical importance, and arteriosclerosis is rare
(c) Atherosclerosis is the most common and important type of arteriosclerosis in humans, and the terms can thus be used interchangeably with little loss of meaning in humans.
(a) In domestic animals, arteriosclerosis is common, but of little clinical importance, and atherosclerosis is rare
(c) Atherosclerosis is the most common and important type of arteriosclerosis in humans, and the terms can thus be used interchangeably with little loss of meaning in humans.
What is the term for accumulation of deposits of lipid, fibrous tissue and mineral in arterial walls, which eventually results in luminal narrowing?
Atherosclerosis
What are three most common anatomic locations where atherosclerosis affects arteries in domestic animals?
Arteries of the (1) heart, (2) mesentery and (3) kidneys
With which two diseases is atherosclerosis associated in dogs?
(1) Hypothyroidism; (2) Diabetes mellitus
In humans atherosclerosis is strongly associated with heart attacks. Is this also the case in dogs?
No.
Which is true:
(a) Atherosclerosis is common in domestic animals and generally leads to clinical disease
(b) Atherosclerosis is infrequent in domestic animals and rarely leads to clinical disease
(b) Atherosclerosis is infrequent in domestic animals and rarely leads to clinical disease
Mineralization of the tunica media (the smooth muscle coat) of arteries is often seen concurrently with endocardial mineralization, and has the same causes. What are four of these causes?
(1) Calcinogenic plant ingestion; (2) Vitamin D toxicosis; (3) Renal disease; (4) Johne’s disease [a granulomatous disease]
Mineralization of the tunica media (the smooth muscle coat) of arteries is often seen concurrently with endocardial mineralization, and has the same causes: (1) Calcinogenic plant ingestion; (2) Vitamin D toxicosis; (3) Renal disease; (4) Johne’s disease [a granulomatous disease]. However, it may be spontaneous in three common veterinary species. Which species are these?
(1) Horses; (2) Rabbits; (3) Guinea pigs
What is the term for inflammation of arteries?
Arteritis
What is the term for inflammation of veins?
Phlebitis
What is the term for inflammation of all types of blood & lymphatic vessels?
Vasculitis
What is the term for inflammation of the tunica intima of an artery?
Endarteritis
What is the term for development of a thrombus?
Thrombosis
What is the term for an intravascular aggregate of fibrin, platelets and blood cells?
A thrombus
What is the term for sudden blockage of an artery by material that was carried there by the blood current?
Embolism. (Most emboli are fragments of thrombi.)
What is the term for the process of a thrombus fragment breaking off its site of formation and being carried away in the blood to cause a blockage further downstream?
Thromboembolism
What is the term for development of an infarct?
Infarction
What is the term for a localized area of ischemic necrosis caused by either blockage either of the arterial supply or the venous drainage?
An infarct
What is the meaning of the term arteritis?
Inflammation of arteries
What is the meaning of the term phlebitis?
Inflammation of veins
What is the meaning of the term vasculitis?
Inflammation of all types of blood & lymphatic vessels
What is the meaning of the term endarteritis?
Inflammation of the tunica intima of an artery
What is the meaning of the term thrombosis?
Development of a thrombus
What is the meaning of the term thrombus?
An intravascular aggregate of fibrin, platelets and blood cells
What is the meaning of the term embolism?
Sudden blockage of an artery by material that was carried there by the blood current
What is the meaning of the term thromboembolism?
The process of a thrombus fragment breaking off its site of formation and being carried away in the blood to cause a blockage further downstream
What is the meaning of the term infarction?
Development of an infarct
What is the meaning of the term infarct?
A localized area of ischemic necrosis caused by either blockage either of the arterial supply or the venous drainage
What is the meaning of the term lymphangitis?
Inflammation of lymphatic vessels (this is a feature of many diseases, and not a disease in its own right)
What is the term for inflammation of lymphatic vessels (a feature of many diseases, and not a disease in its own right)?
Lymphangitis
If you had to name two anatomic sites and species where you would most likely encounter lymphangitis in domestic animals, what would they be?
(1) Subcutaneous lymphatic vessels in distal limbs of horses (various causes, many exotic); (2) Mesenteric lymphatic vessels in ruminants with Johne’s disease (caused by Mycobacterium avium subspecies paratuberculosis)
What is the meaning of the term lymphangiectasia?
Dilation of lymphatic vessels (most commonly seen in the veterinary world as an idiopathic disease affecting the lacteals of dogs and causing a protein-losing enteropathy)
What is the term for dilation of lymphatic vessels (most commonly seen in the veterinary world as an idiopathic disease affecting the lacteals of dogs and causing a protein-losing enteropathy)?
Lymphangiectasia
In what clinical form, and in which species, is lymphangiectasia most commonly seen the veterinary world?
An idiopathic disease affecting the lacteals of dogs and causing a protein-losing enteropathy
Which disease should you suspect in a dog with protein-losing enteropathy, thickened intestinal mucosa, and dilated lacteals?
Lymphangiectasia (an idiopathic disease affecting the lacteals of dogs and causing a protein-losing enteropathy)
What are lacteals?
Lacteals are the lymphatic vessels at the centers of villi
What is the term for lymphatic vessels at the centers of villi?
Lacteals
Which lymphatic-based disease should you suspect in a dog with diarrhea, steatorrhea, hypoproteinemia, & ascites?
Lymphangiectasia (an idiopathic disease affecting the lacteals of dogs and causing a protein-losing enteropathy)
When you find an animal with chylothorax which vessel should you assume has ruptured?
The thoracic duct
What is the name of the condition that results from rupture of the thoracic duct?
Chylothorax
What is chyle?
Chyle is the milky fluid carried from the lacteals to the systemic circulation via the cisterna chyli and thoracic duct. It consists of a mixture of lymph and emulsified fats.
What is the term for the milky fluid carried from the lacteals to the systemic circulation via the cisterna chyli and thoracic duct? It consists of a mixture of lymph and emulsified fats.
Chyle
What are some of the reasons that chylothorax might develop?
(1) Idiopathic / spontaneous rupture of thoracic duct; (2) Chest trauma causing rupture of thoracic duct; (3) Obstruction of the thoracic duct by a neoplasm, abscess or granuloma leading to rupture; (4) Invasion of the thoracic duct by a malignant neoplasm leading to rupture; (5) Right-sided heart failure causing interference of venous return to the heart, with pressure build-up and rupture of the thoracic duct
You perform a necropsy a dyspnoeic cat and find that the pleural cavities are filled with milky fluid. What disease is this?
Chylothorax, caused by rupture of the thoracic duct and leakage of chyle into the pleural spaces. Chyle is the milky fluid carried from the lacteals to the systemic circulation via the cisterna chyli and thoracic duct. It consists of a mixture of lymph and emulsified fats.
What is the term for a benign neoplasm arising from the endothelium of lymphatic vessels?
Lymphangioma (NOT NOT NOT lymphoma, which is a malignant tumor arising from lymphocytes)
What is the term for a malignant neoplasm arising from the endothelium of lymphatic vessels?
Lymphangiosarcoma (NOT NOT NOT lymphosarcoma, which is a malignant tumor arising from lymphocytes)
What is a lymphangioma?
A benign neoplasm arising from the endothelium of lymphatic vessels (NOT THE SAME as lymphoma, which is a malignant tumor arising from lymphocytes)
What is a lymphangiosarcoma?
A malignant neoplasm arising from the endothelium of lymphatic vessels (NOT THE SAME as lymphosarcoma, which is a malignant tumor arising from lymphocytes)
