Histopathology 7: Vascular and cardiac pathology Flashcards
Describe dressler’s syndrome ?
Pericarditis weeks-months after an M.I
What histological findings are seen < 6 hours post MI ?
normal histology
What histological findings are seen 6- 24 hours post MI ?
- loss of nuclei
- Homogenous cytoplasm
- necrotic cell death
What histological findings are seen 1-4 days post MI ?
-infiltration of polymorphs and macrophages to clear debris
What histological findings are seen 5-10 days post MI ?
-debris cleared
What histological findings are seen 1-2 weeks post MI ?
- granulation tissue
- myelofibroblasts depositing collagen
- revascularistation
What histological findings are seen weeks - months post MI ?
-scar tissue
What does Nutmeg liver indicate ?
hepatic cirrhosis most likely due to right sided heart failure
List 5 causes of dilated cardiomyopathy ?
- Alcohol
- post partum
- sarcoidosis
- Haemochromatosis
- genetic: Duchenne’s muscular dystrophy
List 2 causes of Hypertrophic cardiomyopathy ?
- Genetic
- storage diseases
List 3 causes of restrictive Cardiomyopathy ?
- Sarcoidosis
- Amyloidosis
- Radiation
Which type of cardiomyopathy shows myocyte disarray ?
- Hypertrophic
Describe what is meant by HOCM ?
- Hypertrophic obstructive cardiomyopathy
- Septal hypertrophy leading to outflow tract obstruction
Crescendo - decrescendo murmur heard over the left lower sternal edge and bifid pulse.
Most likely diagnosis
HOCM
List 5 features of acute rheumatic fever ?
CASES
Carditis (pancarditis) Arthritis Sydenham's chorea Erythema marginatum Subcutaneous nodules
Which valve is most commonly affected by rheumatic fever ?
Mitral valve
What is the most common causative organism of rheumatic fever ?
Group A streptococcus (tonsillitis)
Histology of the mitral valve and heart shows beady fibrous vegetations, Aschoff bodies and Anitschkov myocytes.
Most likely diagnosis ?
Rheumatic heart disease
Which pathological mechanism leads to Rheumatic heart disease ?
A) Antigenic mimicry
B) Auto-immune
C) Inborn error of metabolism
D) Bacterial colonisation
A) antigenic mimicry
Which type of endocarditis is associated with SLE ?
Libman-sacks endocarditis
caused by antigen-antibody complex deposition
Which organism is the most common cause of acute infective endocarditis in IVDU ?
S.Aureus
Which organism is the most common cause of subacute infective endocarditis ?
Strep. Viridans
Which valve tends to be affected in IVDU with infective endocarditis ?
Right sided valves
Which genetic syndrome is associated with bicuspid aortic valve ?
Turner’s syndrome
Which valve disorder is associated with a mid systolic click and late systolic murmur ?
Mitral valve prolapse
RF for atherosclerosis
age (40-60) gender - postmenopausal women genetics hyperlipidaemia hypertension smoking diabetes mellitus
describe the pathogenesis of atherosclerosis
response to injury hypothesis - chronic inflammatory and healing response of the arterial wall to endothelial injury
endothelial injury - LDL accumulation in the intima
myocytes move to the intima - macrophages - foam cells
cytokine release + lipid accumulation
smooth muscle proliferation also important
GF - PDGF, FGF, TGF-alpha
fatty streak = earliest change
atherosclerotic plaques occur most at points of disturbed flow - ie where arteries branch
consequences = obstruction + rupture
define critical stenosis
when demand>supply
occurs at around 70% occlusion
causes stable angina
describe acute plaque change
rupture - exposes prothrombitic plaque contents
erosion - exposes prothrombotic subendothelial BM
haemorrhage into plaque - increases size
describe IHD
leading cause of death worldwide group of conditions resulting from myocardial ischaemia presents as: - angina - MI - chronic ischaemic HD with HF - sudden cardiac death
plaque sites:
- first few cm of LAD or LCX
- entire length of LCA
what is ACS
stable plaque becomes unstable
generally leads to superimposed thrombus
what is angina pectoris
transient ischaemia that does not produce myocyte necrosis
types = stable, prinzmetal, unstable
stable = no plaque disruption
prinzmetal = due to coronary artery spasm
unstable - disruption of plaque with a superimposed thrombus
define MI
death of cardiac muscle due to prolonged ischaemia
- myocardial blood supply compromised
- loss of contractiliy within 60s
- HF can preceded myocyte death
- potentially reversible
- irreversible after 20-30 mins
LAD > RCA > lateral LV
describe histological changes post MI
under 6 hrs - nomal
6-24 - loss of nuclei, homogenous cytoplasm, necrotic cell death
1-4 days - infiltration of polymorphs then macrophages (clear up debris)
5-10 days - removal of debris
1-2 weeks - removal of granulation tissue, new blood vessels, myofibroblasts, collagen synthesis
weeks - months - strengthening, decellularisisng scar
cinical features of MI
10-15% asymptomatic (elderly, diabetes)
- CK, troponins
- 1/2 deaths within 1 hr
reperfusion injury - can cause stunned myocardium
hibernating myocardium - lower metabolusm
complications of MI
contractile dysfunction - cardiogenic shock arrhythmia myocardial rupture - can cause cardiac tamponade pericarditis RV infarction infarct extension ventricular aneurysm papillary muscle rupture chronic ischaemic heart disease
what is sudden cardiac death
unexpected death from cardiac causes in individuals without symptomatic heart disease
usually due to lethal arrhythmia
often caused by ischaemia-induced electrical instability
featres of cardiac failure
congestive - both sides
left sided - SOB, pul oedema
right sided - peripheral oedemia, nutmeg liver
histology:
- dilated heart
- scarring and thinning of walls
- fibrosis and replacement fo ventricular myocardium
types of cardiomyopathy
dilated (too thin) - progressive loss of myocytes (idiopathic, infective, toxic, hormonal, genetic)
hypertrophic (too thick) - LVH, beta myosin heavy chain ab in some cases
restrictive (too stiff) - impaired ventricular compliance, normal size but big atria
causes of cardiac valve disease
chronic rheumatic valvular disease - immune cross reactivity
- almost always mitral
- M>A>T>P
- button holes
Calcified aortic stenosis - most common
- outflow obstruction
Aortic regurg
- caused by: rigidity (rheumatic, degenerative), destruction (microbial endocarditis), disease of AV ring (eg marfans)
Endocarditis - usually LS unless IV drug users
difference between true and false aneurysm
true - all layers of the wall dilate
false - extravascular hematoma
causes: congenital (marfans), atherosclerosis, hypertension
dissection more common high up
lower more likely to rupture
