8/17- LAB: Pathology of Valvular Heart Diseases Flashcards
Case)
- 42 yo female presented to ER with 2 day Hx of fever, chills, fatigue, and SOB
- PMH: multiple episodes of “strep throat” in childhood, “heart murmur” discovered in teens, recent dental procedure
- PE: diastolic murmur and loud pan-systolic murmur
- Despite intensive supportive therapy, the pt experienced progressive cardiac failure and died
Given the pt’s medical history and clinical findings, what is the likely underlying pathophysiological process?
- Rheumatic fever/rheumatic heart disease associated with Group A strep
- Group A strep pharyngitis -> rheumatic fever -> rheumatic heart disease -> mitral +/- aortic stenosis (always the mitral; if you find symptoms for the aortic, assume mitral as well)
- (Murmur in teens proved that Group A strep progressed to rheumatic fever)
- Dental procedure -> bacteremia -> valvular seeding (vegetations on valves)
- Infective endocarditis
What is the difference between rheumatic fever (RF) and rheumatic heart disease (RHD)?
- Rheumatic fever is an acute multisystem inflammatory disease that may cause rheumatic carditis
- Rheumatic carditis, in turn, my progress to rheumatic heart disease (associated with fibrotic stenosis of heart valves, predisposing them to seeding/vegetations)
What is seen microscopically in acute rheumatic carditis?
Acute rheumatic carditis
- Typically don’t see any lymphoplasmocytic infiltrates in cardiac tissue, but you do here Aschoff bodies (= granulomas)
- Foci of macrophages, lymphocytes, and plasma cells
- The macrophages are called Anitschkow cells (“caterpillar cells”) because of their wavy chromatin
- Giant cells (fused macrophages may be seen here)
What general theories are proposed to explain the lesions of rheumatic fever?
- Antibody-mediated: Abs against the streptococcal M protein can cross-react with self antigens in the heart
- T-cell mediated: CD4+ T cells specific for strep peptides can react with self proteins in the heart. They also produce cytokines that can activate macrophages (such as those found in Aschoff bodies)
(Lecturer favored the 2nd theory due to the great number of macrophages in Aschoff bodies)
Which valves are most commonly involved in rheumatic heart disease?
- Mitral
- Then aortic
(Mitral >> aortic >> tricuspid > pulmonary)
- If you have rheumatic heart disease and have stensois of aortic valve, you will pretty much always have mitral involvement as well
- About 25% of cases involve the aortic valve
What should you be thinking with a pt with tricuspid stenosis?
IV drug use
What are the mitral valve changes in rheumatic heart disease seen here?
Chronic rheumatic mitral stenosis: Thickening and fusion of the chordae tendinae
- Pale tan/white heart valves
- Slightly thickened chordae tendinae that fuse at the top - Thickened valve leaflets
- Valve leaflet commissure fused together
- Possible vegetation on right-ish
This is a fibrotic process
What are the mitral valve changes in rheumatic heart disease seen here?
Chronic rheumatic mitral stenosis: Leaflet thickening and commissural fusion causing “fish mouth”/”button hole” stenosis; thickening and fusion of the chordae tendinae
- “Fish mouth” valve due to fusion of commissures between valve cusps
- Thickened valve
- Fusion of chordae tendinae (rather than going individually into papillae)
What is shown here?
Infective endocarditis: Bulky, friable lesions
- Large vegetation
- Degenerated valve (softened and then fibrotic)
Representative of the etiology causing the acute complications this pt presented with
What is shown here?
Infective endocaditis: Bulky, friable vegetations with valvular destruction
- Representative of the etiology causing the acute complications this pt presented with
What is shown here?
Infective endocarditis: Bulky, friable vegetations with valvular destruction
- Multiple vegetations (due to infectious process)
Representative of the etiology causing the acute complications this pt presented with
What is the difference between acute and subacute infectious endocarditis?
Subacute
- Subacute is more commonly associated with underlying heart disease/damage
- Less virulent strains (Strep viridans)
- Treatment: antibiotics
Acute
- More virulent strains (Staph aureus)
- More damage to heart valves (but not underlying heart disease?)
- Poor prognosis; quick disease course
- Treatment: surgery, replace valve
(TABLE)
What do patients typically die from with infective endocarditis?
Hypoperfusion
Besides infective endocarditis, name 3 other major form of vegetative endocarditis?
- Rheumatic carditis (don’t have to have infection on top of it)
- Nonbacterial thrombotic endocarditis
- Libman-Sacks endocarditis (associated with SLE)
What are the four major forms of vegetative endocarditis? Describe key features.
1. RHD: rheumatic heart disease
- Small, warty vegetations along the lines of closure of the valve leaflets
2. IE: Infective endocarditis
- Large, irregular masses on the valve cusps that can extend onto the chordae
3. NBTE: Non-bacterial thrombotic endocarditis
- Small, bland vegetations
- Usually attached at the line of closure
- One or more may be present
4. LSE: Libman-Sacks endocarditis
- Can have vegetations on both sides of the valve (unique)
- SMall or medium sized vegetaions (on either or both sides)
(PIC)
What is another name for non-bacterial thrombotic endocarditis?
Marantic endocarditis
What is seen here?
Non-bacterial Thrombotic (Marantic) Endocarditis: small, non-destructive vegetations along the lines of closure of the valve cusps
- Hemorrhage-type looking
- Non-destructive! Valves look relatively healthy
What is seen here?
Non-bacterial Thrombotic (Marantic) Endocarditis: almost acellular fibrin thombus loosely adherent to the underlying valve (gray-white); absence of inflammation and organisms
- Acellular, mostly pink fibrin deposition
- Thrombosis; can see vascular components getting caught up in this process
What is shown here?
Chronic rheumatic aortic stenosis:…..
- Fish mouth valve; fusion of commissures
- Deposits typically happen around commissure fusion sites
What it is seen here?
Calcific (senile) aortic stenosis: nodular calcified masses on valve cusps wit sparing of free edges
- Valve leaflets not fused
- Large tan-yellow mass on L leaflet and on others in smaller amount (calcifications)
- Calcifications land on cusps itself and valve has trouble coming back; these masses ultimately protrude into the aortic sinuses, preventing the cusps from opening
What is seen here?
Congenital Bicuspid Valve
- Only see two leaflets; fusion between two cusps (lower)
- Calcifications will land along the protruding raphe between the two cusps
What is seen here?
Calcified aortic stenosis of congenital bicuspid valve
- Calcifications sitting on that raphe
What is seen here?
Normal mitral valve
- Normally closed mitral valve as seen from L atrium
What is seen here?
“Floppy” mitral valve
- Not flat to the point of closure; curved and bulging up (eventually will pop out)
- Curious valvular abnormality involving mitral valve
What is seen here?
Mitral valve prolapse
- Relatively smooth, but almost “look soft”
What is shown here?
Atrial mass: myxoma; a pedunculated, gelatinous mass mottled with hemorrhage, arising from the atrial spetum near the fossa ovalis
- Pedunculated, smooth
What is shown here?
Atrial mass: myxoma; small groups of globular or stellate cells forming characteristic gland- and vessel-like structures embedded ….?
- Clumps of cells; look lay they may be forming vascular patches
- Myxoid cells (although commonly look more blue than this)
