8.4 Valvular Disorders Flashcards
How is the mitral valve affected by Acute rheumatic fever vs Chronic rheumatic fever
Acute: mitral regurg (from endocarditis vegetations)
Chronic: mitral stenosis (from scarring)
Acute rheumatic fever
- bacteria?
- mech
- timeframe
- Strep Pyo (group A beta-hemolytic), which causes strep pharyngitis (strep throat)
- molecular mimicry–bacterial M protein resembles heart tissue
- occurs 2-3 weeks after strep throat
How to diagnose acute rheumatic fever?
JONES criteria:
Joint–migratory polyarthritis (pain migrates from joint to joint)
O–Heart: pancarditis (endo-, myo-, percarditis)
Nodules, subcutaneous
Erythema marginatum (rash with red border)
Syndenham’s chorea
Acute rheumatic fever:
-What are all the ways the heart is affected?
- Pancarditis (endo, myo, pericarditis)
1. Endocarditis - vegetations grow on mitral valve, cause mitral regurg
2. Myocarditis - Aschoff bodies (granuloma from inflammation with Anitschkow cells, giant cells, fibrinoid material)
- Anitschkow cells are macrophages with ‘caterpillar nuclei’
3. Pericarditis - friction rub, chest pain
Aschoff bodies
Granulomas (inflammatory accumulation of macrophages) found in myocardium in Acute rheumatic fever.
-contain Anitschkow cells, giant cells, fibrinoid material
Anitschkow cells
Reactive histiocytes with ‘caterpillar nuclei’
- found inside Aschoff bodies in myocardium
- myocarditis of acute rheumatic fever
what is the main cause of death in acute rheumatic fever?
-myocarditis
Chronic rheumatic fever
-characteristics
- valve scarring, leads to stenosis by fusion of valve commissues. causes mitral stenosis, sometimes also aortic stenosis
- valve damage can predispose to infectious endocarditis
Aortic stenosis
- causes
- how to differentiate
- ‘wear and tear’ (old age)
- Chronic rheumatic fever
- difference is that in chronic rheumatic fever, the stenosis is caused by fusion of commissures, and the pt will also have mitral stenosis.
Aortic stenosis:
-what congenital disorder is a risk factor for early onset?
- Bicuspid aortic valve.
- increased wear and tear
Aortic stenosis
-describe murmur
- systolic murmur
- systolic ejection click followed by crescendo-descrendo
Aortic stenosis
-complications (3)
- LV hypertrophy, L side heart failure
- Decreased systemic blood causes angina, syncope with exercise
- Microangiopathic hemolytic anemia–RBC damaged while crossing stenosed valve (forms schistocytes)
Aortic regurg
-causes (3)
- Isolated root dilation (most common, usu idiopathic)
- Root dilation from aortic aneurysm/dissection
- Valve damage (eg endocarditis)
aortic regurg
-murmur
- diastolic murmur
- early, blowing
aortic regurg
-clinical findings/symptoms
- LV dilation, eccentric hypertrophy (volume overload)
- Hyperdynamic circulation, from increased pulse pressure
- diastolic pressure decreased b/c regurg
- systolic pressure increased b/c returned blood increases stroke volume
- Symptoms: bounding pulse (‘water-hammer pulse’), pulsating nail bed (Quincke pulse), head bobbing
mitral valve prolapse
- what is it
- cause
- mitral valve balloons (floppy valve) during systole
- caused by myxoid degeneration (accumulation of ground substance) on valve
- unknown etiology, seen in Marfan’s and Ehlers-Danlos
mitral valve prolapse
- murmur
- how is murmur affected by squatting.
- complications
- mid-systolic click, followed by regurg murmur
- squatting decreases sound (opposite of mitral regurg) b/c a fuller ventricle means chordae are tighter to help keep the valve closed.
- valve damage predisposes to infective endocarditis
- also mitral regurg
Mitral regurg
- most common cause
- other causes (4)
- mitral valve prolapse complication
- L sided heart failure (LV dilation pulls valve apart)
- infective endocarditis
- acute rheumatic fever
- MI–papillary muscle rupture
Mitral regurg
- murmur
- how can pt bx change murmur
- systolic murmur that is louding with:
1. if pt squats, this will increase arterial resistance and decrease LV stroke volume. This pushes more blood backward through mitral valve.
2. If pt expires, increased return to LA
Mitral regurg
-complication
LV volume overload, L sided heart failure
Mitral stenosis
- main cause
- clinical features/complications (2)
- chronic rheumatic disease (scarring of valves with commissure fusion)
1. LA Volume overload, leads to pulm congestion and eventual R sided failure.
2. Conduction problems from dilated LA means Atrial fibrillation and mural thrombus risk
mitral stenosis
-murmur
- diastolic murmur
- opening snap and rumble
