Cardiovascular Pathalogical Anatomy Flashcards
Rigor morris of the myocard
Rigid ventricular walls and empty left ventricle
What is the difference between clots formed anti Mortem and post mortem
Post mortem clots are red, free from attachment to any surrounding structures and found in arteries, the right ventricle and large vessels at the base of the heart.
Anti - mortem clots may be free (blood clot) or attached = thrombus
The discovery of pale chicken fat clots is suggestive of
They have few erythrocytes = animal may have suffered from severe anemia, or prolonged agonal period (time between fatal event and death).
Macroscopic picture of Hb imbibition
Imbibition is the result of red blood cell lysis in tissues starting more than 12. Hours after death - Hb is liberated from erythrocytes and gives a diffuse red/pink staining to tissues.
In the heart there is a diffuse red colouration of the endocard and epicardium that imitates haemorrhage!
In myocardial cell necrosis we expect to see
Leukocytic invasion and phagocytosis of sarcoplasmic content - sarcolemma tubules and condensed interstium with vessels remain. Rarely see myocyte regeneration, unless in very young animals and avians.
Patent ductus arteriosus
A persistent channel between pulmonary artery and aorta in foetal life (allows blood to bypass lungs in uteri) should convert to ligamentum arteriosum post natally, however in k9 breeds such as poodle collie and Pomeranian this does not happen.
Describe a atrial septal defect
Foremen ovale connection between atria in foetus fails to close postnatal in breeds such as boxer, Doberman and Samoyed.
Describe Ventricular septal defect
Failure of the interventricular septum to form fully (usually upper membranous part rather than lower muscular part) as a result shunting of blood occurs between the cavities. Common in English bull dog, springer spaniel and westies.
What is a pulmonic stenosis
Narrowing of the pulmonary artery - leads to hypertrophy of the right ventricle due to increased intraventricular pressure. Common in beagles, chihuahuas and English bull dogs.
Valvular hameatomas or hemocyts are ??
Bulging blood filled lesions on the edge of atrioventricular valves commonly found in young ruminants. They usually regress after several months of age and don’t effect heart function.
What is a persistent right aortic arch
Right aortic arch fails to regress normally and therefor the oesophagus and trachea are trapped between it and the ligamentum arteriosum at the level of the base of the heart.
Animals suffer from oesophageal dilation, regurgitation, aspiration pneumonia. GSDs and red setters are susceptible.
What is ectopia cordis
Congenital development abnormality of the heart - heart sits outside the thoracic cavity.
Extra thoracic, pre eternal or intro abdominal
Dislocation within the thorax occur due to asymmetric pressure ie. in a congenital diaphragmatic hernia, or pleural effusion.
A congenital absence of a pericardium can occur in dogs
What is endocardial fibro-elastosis
Diffuse endocardial thickening when any of the heart chambers remain dilated for a long period of time
Primary - left ventricular hyper trophy & dilation and diffuse endocardial thickening by collagen and elastic fibres, without a associated cardiac malformation. ** Burmese cats
Secondary - heart disease in turkeys: cardiomyopathy left ventricular hypertrophy and dilation - heart has a round shape.
Non inflammatory fluid accumulated in the pericardial sac is associated with which kind or cardiovascular disturbance
Circulatory disturbances which causes findings such as hydropericardium, haemopericardium
Characterise hydro pericardium
Accumulation of clear to light yellow watery serous fluid in the pericardial sac.
Acute - pericardial surfaces and smooth and shiny
Chronic- epicardium opaque, Fibrinous thickening, rough granular
Causes: generalized anasarca, congestive heart failure, nutritional (low protein), neoplastic metaplasia to pericardium, lymphoma of myocardium.
Characterise haemopericardium
Accumulation of blood in pericardial sac.
Sudden death - cardiac tamponade
Causes: atrial rupture in dogs, intrapericardial aortic rupture in horses, complication of intracardiac injection
What is the cause of serous atrophy of fat in the heart
Rapid mobilisation of fat deposits occurs following anorexia, starvation and cachexia.
Normally animals have abundant white epicardia’s fat deposits particularly in the ateioventricular junction - this fat is lysed and fat vacuoles of lipocytes are small, replaced by protein rich fluid. At the same time as an increase in interstitial fluid the deposits are converted to grey gelatinous masses with small white foci of necrotic fat.
Lipocytes are atrophic and surrounded by oedema.
What affect may visceral gout of snakes and birds have on the pericardium
Urate deposits are found in pericardium - serosal surface appears thickened and white.
Name the different types of pericarditis
Fibrinous
Suppurative
Constrictive
Characterise fibrinous pericarditis
Rarely significant exudation of fluid = no distension of pericardial sac.
Fibrin exudation from damaged vessels or inflammatory response to haematogenous infection, starts at the base of the heart and spreads to cover pericardium and epicardium.
Both pericardial surfaces appear rough and are covered by yellowish fibrin deposits, the pericardium microscopically appears congested and has a layer of fibrin that is stained eosinophillically with NEU.
With time fibrous adhesions may form between the pericardial surfaces following fibrous organisation.
Causes:
Cattle: pasturellosis, black leg, coliform Septicaemia, SBE sporadic bovine encephalitis
Pigs: glassers disease, streptococcal infection, pasturellosis, enzootic mycoplasmal pneumonia, salmonellosis
Horses: streptococcal infection
Birds: psittacosis
Characterise suppurative pericarditis
Purulent/ suppurative exudate in the pericardial sac of cattle often due to traumatic reticuloperitonitis (HARDWARE DISEASE)
foreign bodies such as nails and wire penetrate the reticulum, diaphragm and pericardial sac introducing infection.
Cattle may survive for weeks or months before death from congestive heart failure and Septicaemia.
Pericardial surfaces are thickened and white rough shaggy masses of Fibrinous tissue with an accumulation of thick foul purulent exudate in the sac.
Also seen in horses and cats associated with empyema.
Characterise constrictive pericarditis
Chronic inflammatory lesions with extensive fibrous proliferation and adhesions in the pericardial space.
Advanced adhesions cause pericardial sac obliteration and constriction of the heart which interferes with cardiac filling. Compensatory mechanisms such as myocardial hypertrophy, chambers are lower in volume which also contributes to eventual heart failure.
Degenerative disorders of the endocardium
Endocardial Mineralisation
endocardial fibrosis
Valvular fibrosis / endocarditis
Mineralisation of the endocardium
Vit D toxicosis, carcinogenic plant intoxication (vit d analogs) ie. Enzootic calcinosis
Large firm white plaques on the endocardial surface of the heart and intima of large elastic arteries.
Endocardial fibrosis
Develops following chronic cardiac issues - chronic heart dilation in cattle with johns disease
Dogs that have had a previous uremic episode - lesions caused by ulcerative endocarditis in left atria, heal but fibrotic tissue remains.
Characterise valvular endocarditis / valvular fibrosis
Age related disease in K9s
MOST COMMON CAUSE OF CONGESTIVE HEART FAILURE IN OLD DOGS
Lesions are more frequent on mitral/ bicuspid valve (left atrium left ventrical two cusps) than tricuspid (right atrioventricular 3 cusps)
Valves are short and thick with diffuse or nodular and smooth appearance instead of rough
Histology: valves show fibroblastic proliferation and deposition of mucopolysacharides
Which type of lesions are seen in endocarditis and what do they look like
Mural
Valvular
Cause: bacterial infections that result in bacteremia or strongylus vulgaris/ mycotic infections in horses.
Acute ulcerative endocarditis of the left atrium - uremic syndrome in dogs.
Macroscopically: Adhering friable yellow to grey masses occlude valve orifices - they are made up of fribrous CT and look wart like.
Microscopically: there are layers of fibrin surrounding bacterial colonies, with NEU infiltration and granulation tissue in chronic lesions.
Characterise ulcerative endocarditis of canines
Acute condition of the left atria - distinctive lesion caused by acute renal insufficiency.
Swelling of interstitial spaces in subendocardium or tunica intima of arteries —> either heals with some fibrosis or progresses to necrosis of cells, collagen, elastic and reticular fibres. These ulcerations can perforate the wall of the atrium causing thrombi formation and heavy deposition of calcium salts.
If the renal insufficiency is re established then the lesion may heal leaving irregular patches of sclerosis - intact endothelium covers white plaques of mineralisation.
Myocardial growth disturbances
Hypertrophy - increase in muscle mass due to an increase in myocyte size. Usually a secondary compensatory response to increased workload of the heart.
ECCENTRIC hyper trophy = enlarged cardiac chambers (dilation) walls are normal to thinner than normal caused by increased blood volume load a result of valve insufficiencies and septal defects (shunting).
CONCENTRIC hypertrophy = small cardiac chambers with thickened walls caused by an increase in pressure/load due to valve stenosis, systemic hypertension, pulmonary disease (cor pulmonale).
Common causes of RIGHT ventricular hypertrophy
- Dirofilariasis (heart worm) K9
- Congenital pulmonary artery stenosis K9
- Brisket disease in cattle
- Chronic vesicular emphysema in equines
Causes of LEFT ventricular hypertrophy
Congenital sub aortic stenosis in K9’s
Define fatty infiltration of the heart
Associated with obesity, increased numbers of lipocytes are deposited between myocardial fibres.
Define fatty degeneration of the myocard
Accumulation of sarcoplasmic lipid droplets within cardiomyocytes. Heart is pale and flabby, this lesion occurs in systemic disorders such as anaemia, toxaemia and copper deficiency.
