Histopathology 6 - Vascular and Cardiac pathology Flashcards
What are the 3 stages of atheroma development?
- Raised lesion
- Soft lipid core
- White fibrous cap
Recall the 7 steps of atheroma pathophsyiology
- Endothelial injury
- LDL enters intima and gets trapped in intimal space
- LDL is converted into oxidised LDL –> inflammation
- Macrophages take up OxLDL via scavenger receptors –> foam cells
- Foam cell apoptosis –> inflammation and cholesterol deposition to form plaque core
- Endothelium expresses more adhesion molecules –> more macrophages and T cells enter plaque
- VSMCs form fibrous cap
What % occlusion of a vessel lumen by atheroma is considered ‘critical stenosis’?
70%
What causes prinzmental angina?
Coronary artery spasm
Which parts of the cardiac muscle are affected by an infarction of the LAD?
Anterior wall of left ventricle, anterior septum and apex
Which parts of the cardiac muscle are affected by an infarction of the RCA?
Posterior wall of left ventricle, posterior septum and posterior wall of right ventricle
Which parts of the cardiac muscle are affected by an infarction of the LCx?
Lateral wall of left ventricle
What are the 4 most important complications of MI?
- Contractile dysfunction (eg cardiogenic shock)
- Arrhythmia
- Myocardial rupture (occurs at day 4-5)
- Pericarditis
What is Dressler’s syndrome?
Pericarditis occuring weeks-months post-MI
What is the average time between MI and myocardial rupture?
4-5 days
What is the prognosis of papillary muscle rupture following MI?
Rubbish - very high mortality
What is the most common cause of sudden cardiac death?
Lethal arrhythmia
What is restrictive cardiomyopathy?
When there is impaired ventricular compliance (contractibility)
Normal size heart but with large atria - may be due to amyloidosis
Recall 3 possible causes of aortic regurgitation
Infective endocarditis
Marfan’s
Ankylosing spondylitis
What is Monckeberg atherosclerosis?
Focal calcification of the media of small-medium sized vessels; no associated inflammation
What histological findings would be found within 6 hours of an MI?
Normal histology and normal CK-MB
What histological findings would be found 6 -24 hours following an MI? (3)
- Loss of nuclei
- Homogenous cytoplasm
- Necrotic cell death
What histological findings would be found 1-4 days following an MI?
Infiltration of polymorphs and macrophages (to clear up debris)
What histological findings would be found 5-10 days following an MI?
Removal of debris
What histological findings would be found 1-2 weeks following an MI?
Granulation tissue
New blood vessels
Myofibroblasts
Collagen synthesis
What histological findings would be found in the months following an MI?
Strengthening, de-cellularising scar tissue
Recall the possible complications of MI
Mnemonic = PACE MAKERED
Papillary muscle dysfunction
Arrhythmia
Ccf
Effusion (pericardial)
Mural thrombus
Aneurism (ventricular)
(K)ontractile dysfunction
Early pericarditis
Rupture of venticular wall
Elevation of ST segment
Dressler’s syndrome
What types of cardiomyopathy can be caused by sarcoidosis?
Dilated and restrictive
Which type of cardiomyopathy is associated with alcohol misuse?
Dilated
Is the pathology of cardiomyopathy systolic or diastolic dysfunction in
a) dilated CM
b) hypertrophic CM
c) restrictive CM?
Dilated: systolic
Hypertrophic and restrictive: diastolic
What is the HOCM?
Hypertrophic obstructive CM = septal hypertrophy resulting in an outflow tract obstruction (usually get LV hypertrophy)
What mutation is associated with Hypertrophic CM?
Beta-myosin heavy chain
(Beta-HMC - HMC is HCM rearranged)
Recall the major criteria for Rheumatic fever diagnosis
CASES
Carditis
Arthritis
Sydenham’s chorea
Erythema marginatum
Subcutaneous nodules
What is the main pathogen in rheumatic fever?
Lancefield group A strep
How is ‘antigenic mimicry’ involved in rheumatic heart fever?
Cell-mediated immunity and antibodies to streptococcal antigen cross-react with myocardial antigens
How are vegetations seen on heart valves in rheumatic fever described?
Small and warty, “verrucae”
Differentiate the likely causative organisms in acute vs subacute infective endocarditis
Acute: Staph aureus/ pyogenes
Subacute: strep viridans/ epidermis/ HACEK/ coxiella/ candida/ mycoplasma
Recall the major and minor Duke criteria for infective endocarditis
Major:
+ve blood culture growing typical IE organism OR 2 +ve cultures >12hrs apart
Minor:
- RF (prosthetic valve, IVDU, congenital valve abnormalities)
- Fever >38
- Thromboembolic phenomena
- Immune phenomena
- Pos BCs not meeting major criteria
How many of Duke’s criteria are needed for diagnosis of infective endocarditis?
2 major
1 major and 3 minor
5 minor
What abnormality in the mitral valve might be caused by rheumatic fever vs IE?
RhF: mitral stenosis
IE: mitral regurgitation
Features of Vulnerable atheromatous Plaques
- Lots of foam cells or extracellular fluid
- Thin fibrous cap
- Few smooth muscle cells
- Clusters of inflammatory cells
What is angina pectoris?
Transient ischaemia that does NOT produce myocyte necrosis
Immune cell progression in myocardial infarctoin
- day 1-3: neutrophils eating damaged myocardium
- day 10-14: macrophages
- after 2 months: scarring
What can happen when blood re-enters area of myocardial necrosis?
Reperfusion Injury
- oxidative stress, calcium overload and inflammation can cause further injury
Congestive heart failure meaning
when it affects both sides of the heart
Effect of L heart failure
SOB, pulmonary oedema (affects the lungs)
Effect of R heart failure
peripheral oedema, nutmeg liver
Most common cause of right-sided heart failure
Left-sided heart failure
Aetiology of dilated cardiomyopathy
progressive loss of myocytes (get big/dilated heart)
What precedes rheumatic fever?
streptococcal throat infection (2-4 weeks before)
Tx of rheumatic heart fever
Benzylpenicillin
MOST COMMON cause of aortic stenosis
Calcific Aortic Stenosis
True vs false aneurysm
- True- involves all layers of the wall
- False- extravascular haematoma (i.e. a rupture and haematoma that forms)
Which site is more likely to have dissecting aneurysm, and which is more likely to have rupturing aneurysm?
- Dissecting: aortic arch
- Rupturing: abdo aorta (AAA)
