Cardiovascular Pathology

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Cardiovascular Pathology
2015-03-31 12:54:26
Cardiovascular Pathology

Vet Med - Module 10
Show Answers:

  1. Define heart failure
    Heart failure is when the heart is unable to generate sufficient output to meet the demands of the body
  2. List the 5 mechanisms of heart failure
    • Inability of the heart to expand
    • Damage to the myocardium
    • Increased resistance to outflow
    • Valvular defects
    • Irregular rhythms
  3. Where would you see oedema in a) left b) right sided heart failure?
    • a) pulmonary oedema
    • b) venous congestion and peripheral oedema
  4. List some of the clinical signs of right sided heart failure
    Jugular distention, hepatic and splenic enlargement, ascites and peripheral oedema
  5. What appearance does chronic venous congestion cause a liver to have PM?
    A 'nutmeg' liver
  6. List some clinical signs of left sided heart failure
    Cough and dyspnoea
  7. What are the three intrinsic cardiac responses to heart failure?
    Cardiac dilation, cardiac hypertrophy and increased cardiac rate
  8. How does the RAAS system try to compensate for heart failure?  Why does this not work long term?
    • A decrease in renal perfusion triggers renin production.  Angiotensinogen is produced in the liver which produces angiontensin I, then II in the lungs.  This increases water and salt retention which increases the circulating volume, therefore increasing preload, CO and BO.  
    • In the long term there are degenerative changes to the kidney causing proteinuria and cardiac remodelling and myofibre dysfunction.
  9. What is Cor Pulmonale?
    Right sided heart failure secondary to pulmonary disease e.g. COPD.
  10. List the layers of the heart wall from outside to inside
    Pericardium, (pericardial space), myocardium, endocardium
  11. Define hydropericardium
    Fluid (transudate or modified tranudate) gathering between the visceral and parietal layers of the pericardium
  12. Define haemopericardium
    Blood in the pericardium
  13. What is a common cause of haemopericardium in a) dogs b) horses?
    • a) ruptured atria
    • b) ruptured aorta
  14. Define pericarditis
    Inflammation of the pericardium
  15. What is a common cause of pericarditis in cattle?
    Hardware disease - bovine traumatic reticulopericarditis
  16. Define cardiac tamponade
    Acute cardiac compression due to accumulation of fluid
  17. What is a conduction disorder?
    Abnormalities in the conduction pathway of the heart
  18. What do conduction disorders often result in?
  19. What is an arrhythmia?
    A variation from the normal rhythm of the heart
  20. Which species commonly have primary conduction disorders that disappear with increased activity?
  21. Give an example of an inherited arrhythmia in dogs
    • Arrhythmogenic right ventricular cardiomyopathy - boxers
    • Dilated cardiomyopathy - doberman
    • Inherited ventricular arrhythmia - GSD
  22. What is 'sick-sinus syndrome'?
    A group of disorders involving the sino-atrial node that cause periods of ventricular standstill and paroxysms of supra ventricular tachycardia, which leads to syncope (loss of consciousness due to cerebral hypoperfusion)
  23. What breed of dog is prone to getting 'sick-sinus syndrome'?
    Miniature Schnauzer
  24. Define the following types of heart block a) first degree b) second degree c) third degree
    • a) delay of impulse through AV node
    • b) intermittent failure to conduct through AV node with dropped beats
    • c) complete block
  25. Describe normal cardiac muscle
    Striated, intercalated discs, central nuclei
  26. Give examples of when the heart may undergo atrophy/hypertrophy
    • atrophy - bed rest, wasting diseases
    • hypertrophy - exercise, hypertension, valvular stenosis
  27. What is the difference between concentric hypertrophy and eccentric hypertrophy?
    Concentric hypertrophy is when there is an increase in myoctye width due to addition of sarcomeres in parallel, whereas eccentric hypertrophy is when there is addition of sarcomeres in series.
  28. Which is caused by a volume/pressure overload: concentric/eccentric hypertrophy?
    • Volume overload - eccentric
    • Pressure overload - concentric
  29. Describe the differences in the following between physiological and pathological hypertrophy: heart function, gene expression, fibrosis/apoptosis and heart size
    • Heart function - physiological = increase in HR, pathological = initially the heart can counterbalance any stress but long term the heart develops depressed cardiac function and goes into heart failure
    • Gene expression - physiological - normal gene expression, pathological = fetal gene reactivation
    • Fibrosis/apoptosis - physiological = none, pathological = intracellular fibrosis formation and increased number of apoptotic cardiomyocytes
    • Heart size - both hypertrophies result in bigger heart size
  30. List the 4 types of myocardial diseases
    Degneration, necrosis, myocarditis, and cardiomyopathies
  31. List four types of myocardial degeneration that are sublethal
    Lipofuscinosis, fatty degeneration, myocytolysis and vacuolar degeneration
  32. Describe what a lipofuscinosis heart would look like
    A chocolate brown colour instead of pink/red
  33. Describe the stages in myocardial necrosis
    A normal cardiac myocyte undergoes injury which results in hyaline necrosis.  There is then macrophagic invasion, as necrosis triggers inflammation, and eventually healing with fibrosis.
  34. Give a cause of myocardial necrosis
    White muscle disease in calves (selenium/vit E deficiency)
  35. Give a cause of myocarditis in dogs
    Canine parvovirus
  36. Histologically, what can provide a definitive diagnosis of canine parvovirus?
    Brick-like inclusions in the nuclei of heart muscle cells
  37. What parasite can cause parasitic myocarditis in sheep?
    Cysticercus ovis
  38. What biochemical markers can be detectable from 1-3hr to 10-14 days after damage to the myocardium?
    Creatinine kinase, troponins
  39. Which is more specific to heart damage: creatinine kinase or troponins?
  40. What are the four types of primary cardiomyopathies?
    Hypertrophic, dilated, restrictive and arrhythmogenic right ventricular
  41. What can cause secondary cardiomyopathies in cats?
    Hyperthyroidism and taurine deficiency
  42. What can cause secondary cardiomyopathies in various species?
    Drugs, toxins, nutritional disorders
  43. In what breeds of cat is primary hypertrophic cardiomyopathy familial?
    Maine Coon and American Shorthair
  44. What type of primary cardiomyopathy is the least common?
    Restrictive cardiomyopathy
  45. What happens in restrictive cardiomyopathy?
    There is increased ventricular stiffness (usually abnormal fibrosis) which causes loss of left ventricular diastolic function
  46. What type of primary cardiomyopathy is most common in dogs?
    Dilated cardiomyopathy
  47. Define valvular endocarditis
    Inflammation of the heart valves
  48. Define valvular endocardiosis
    Degeneration of the heart valves
  49. What breed of dog is prone to valvular endocardiosis?
    Cavalier king charles spaniels
  50. What does valvular endocardiosis look like on gross inspection?
    Smooth, pearl-white thickenings on valve leaflets, +/- thickening of chordae tendinae
  51. What valve is there most frequently endocardiosis on?
    Mitral valve
  52. Which valve is most commonly affected by endocarditis in the following species: a) cattle b) pigs, sheep and dogs c) horses?
    • a) tricuspid valve
    • b) mitral valve
    • c) aortic valve
  53. What does endocarditis appear like on gross inspection?
    Friable, yellow and grey masses or vegetations on heart valves
  54. Define congenital
    Present at birth, as a congenital abnormality or defect
  55. Define hereditary
    Transmitted from parent to offspring - inherited
  56. Define familial
    Present in some families and not others or occurs in more family members than would be expected by chance
  57. Define acquired
    Originating after birth, NOT caused by hereditary or developmental factors but by a reaction to environmental influences outside of the organism
  58. What is the foramen ovale?
    The foetal opening between the right and left atria
  59. What is the ductus arteriosus?
    The foetal shunt between the pulmonary artery and aorta
  60. What is the ductus venosus?
    The shunt that connects the portal and umbilical veins to the vena cava
  61. What are the 3 main categories of congenital defects?
    • Failure of closure of foetal structures
    • Septal defects
    • Great vessel defects
  62. What condition results from a persistent ductus venous?
    Hepatic encephalopathy - build up of ammonia in the blood due to incomplete detoxification in the liver which effects the brain
  63. Where does blood flow from and to in an atrial septal defect?
    From the LA to the RA
  64. Which chamber distends in an atrial septal defect?
    The right atrium
  65. What chamber hypertrophies in a ventricular septal defect?
    Right ventricle
  66. What can happen to blood flow in a chronic ventricular septal defect?
    Pressure becomes higher on the right side so blood flows from the RV to LV
  67. What does valvular insufficiency result in?
    Regurgitation of blood
  68. What is valvular stenosis?
    Narrowing of the valves
  69. Which valves typically suffer from a) insufficiency b) stenosis?
    • a) mitral and tricuspid 
    • b) aortic and pulmonary
  70. What is the term for a right to left shunt?
    Tetralogy of Fallot
  71. Does a right to left shunt result in too much or too little blood flowing to the lungs?
    Too little
  72. Why is there cyanosis as a result of tetralogy of fallot?
    As deoxygenated blood enters systemic circulation
  73. What congenital defects are the following species most susceptible to: a) dog b) cat c) cattle d) pigs e) horses
    • a) patent ductus arteriosus, pulmonic stenosis, subaortic stenosis
    • b) mitral dysplasia
    • c) atrial septal defect, ventricular septal defect
    • d) uncommon
  74. Describe what happens in an animal with a patent right aortic arch
    Food gets stuck in the oesophagus cranial to the ligamentum arteriosum. This causes megaoesophagus and regurgitation of food.
  75. With regards to blood vessels, define a) hyperaemia b) congestion
    • a) increased inflow
    • b) decreased outflow
  76. Define erythema
    Redness in skin
  77. What are the following composed of: a) transudate b) modified transudate c) exudate?
    • a) water
    • b) water, protein, a few cells
    • c) water, protein, more cells
  78. What direction does oncotic pressure move water in?
    It moves water into blood vessels
  79. What protein is responsible for most of the oncotic pressure?
  80. What direction does hydrostatic pressure move water in?
    It moves water out of blood vessels
  81. Define ascites
    Fluid/oedema in the abdominal cavity
  82. What are the four mechanisms of oedema formation?
    Vascular permeability is increased, intravascular hydrostatic pressure is increased, intravascular oncotic pressure is decreased, lymphatic drainage is decreased
  83. Where do the following species tend to get oedema formation: a) dog b) cat c) horse d) cattle?
    • a) ascites
    • b) pleural effusion
    • c) forelimbs (and scrotum)
    • d) brisket
  84. What can cause a decrease in oncotic pressure?
    Hypoalbuminaemia due to liver failure, intestinal malabsorption, renal failure, parasitic infection
  85. What are the three components of Virchow's triad?
    Endothelial injury, abnormal blood flow and hypercoagulability
  86. List 5 things that can disrupt normal circulation
    Torsion, rupture, vascular thickening, vasculitis and thrombosis
  87. Which blood vessel can rupture in horses?
  88. Define the following: a) petechiae b) purpura c) ecchymoses d) haematoma e) haemothorax f) haemoperitoneum
    • a) pinpoint haemorrhages
    • b) medium sized haemorrhages
    • c) large haemorrhages
    • d) localised, extravascular collection of blood
    • e) free blood in the abdomen
  89. What is an aneurysm?
    A dilation/thickening of a blood vessel wall
  90. What is a dissecting aneurysm?
    A split/tear in the wall which causes weakness.  If blood moves into here it can form a clot.
  91. What blood vessel can be damaged by a guttural pouch infection?
    The internal carotid
  92. What can rupture of the internal carotid result in?
    Epistaxis or sudden death
  93. What is the term for vascular thickening i.e. narrowing of the lumen with loss of elasticity?
  94. What is the difference between dystrophic calcification and metastatic calcification?
    • Dystrophic - mineral deposits secondary to tissue damage
    • Metastatic - due to hypercalcaemia
  95. What condition in dogs can lead to atherosclerosis?
  96. How does hypothyroidism cause atherosclerosis?
    Hypothyroidism causes depressed metabolic rate, decreased fat metabolism, accumulation of lipid in plasma which sticks to the side of vessels.  Fibro-fatty plaques stick to the lipids and then you get calcium deposition on top of this.
  97. What is vasculitis?
    Inflammatory cells within the blood vessel wall
  98. Give an example cause of vasculitis in cats
    Feline infectious peritonitis
  99. Give an example cause of vasculitis in ruminants
    Navel ill
  100. Give an example of parasitic cause of vasculitis
    Angiostrongylus vasorum
  101. A solid mass forming in blood vessels from blood constituents is called a ...?
  102. What is a 'saddle thrombi'?  What species is this most common in?
    • A saddle thrombi is a thrombus that moves from the heart to sit across the bifurcation of the aorta
    • Cats
  103. How do cats with a saddle thrombus present?
    Cold back legs, posterior paraparesis, no femoral pulse
  104. What are the three causes of venous thrombosis
    • Iatrogenic eg catheterisation
    • Portal vein thrombosis
    • Venal caval syndrome
  105. Define vena caval syndrome
    Occlusion of the vena cava by infiltration, thrombosis or compression
  106. What is vena caval syndrome secondary to in a) dogs b) cattle
    • a) heart worm infection, neoplasia
    • b) hepatic abscesses
  107. What is it called when lymphatic fluid escapes into the a) thorax b) abdomen?
    • a) chylothorax
    • b) chylous ascites
  108. Give an example of an infectious cause of lymphangitis
    Johne's disease, Actinobacillosis