Valvular Disorders & Infective Endocarditis Flashcards
Which valve is most commonly affected?
- the mitral valve
What is the most common cause of aortic stenosis?
- calcific aortic stenosis; calcified masses on the valvular cusps impede valve opening
- (there is NO fusion of the commissures here)
What is the most common congenital valvular lesion?
- bicuspid aortic valve
Mitral valve regurgitation is most commonly due to __________; mitral valve stenosis is most commonly due to ___________.
- regurgitation: myxomatous degeneration (floppy valve, ballooning of the leaflets)
- stenosis: rheumatic valvular disease (“fish mouth”)
Rheumatic Heart Disease is cardiac inflammation via which organism? What is the pathology behind the disease?
- group A beta-hemolytic streptococci
- pathogenesis: the Ab produced against these bacteria also target the heart (bacterial M protein resembles human tissue: molecular mimicry)
A patient with Rheumatic Heart Disease will often have had what a few weeks back?
- pharyngitis (1 - 3 weeks before)
- (the bacteria often invade the pharynx first before leading to the systemic rheumatic fever)
Microbial invasion of the heart valves and endocardium (ie, the endocardium lining the valves) is known as:
- infective endocarditis
Pathogens of Infective Endocarditis
- Strep. viridans: most common; low virulence; infects previously damaged valves
- Staph. aureus: most common cause in IV drug users; high virulence; infects healthy valves
- Staph. epidermidis: most common cause of prosthetic valve infection
In Infective Endocarditis, what results in janeway lesions, splinter hemorrhages, and osler nodes?
- septic embolization
HACEK Organisms
- organisms that can cause infective endocarditis, but result in NEGATIVE blood cultures
Rheumatic Valvular Disease is a result of what? Which valves does it usually affect?
- it’s a result of repeated exposure to the pathogen, resulting in scarring of the valves
- it can affect the mitral and aortic valves (mitral valve is more commonly affected)
What do we see in Rheumatic Fever/Rheumatic Heart Disease?
- JONES criteria:
- Joint issues (arthritis), “O” heart problems (pancarditis), Nodules in the skin, Erythematous rash, Sydenham’s chorea (involuntary spasms)
- fusion of valvular commissures and shortening of chordae leads to “fish mouth”
On histology, what do we see in Rheumatic Heart Disease?
- Aschoff bodies with Anitskow (“caterpillar”) cells
- a result of inflammation of the myocardium
Classic Triad of Symptoms for Aortic Stenosis
- chest pain, heart failure (dyspnea, PND), and syncope
What murmur is associated with Aortic Stenosis?
- a pan-systolic crescendo-decrescendo mumur
What is the key finding needed to diagnose Infective Endocarditis?
- bacteria in the blood-stream
- specifically, blood cultures persistently positive for one of these organisms, from cultures drawn more than 12 hours apart
Infective Endocarditis most commonly affects the:
- mitral valve (aortic valve is the 2nd most common)
Rheumatic Fever is most commonly seen in what demographic?
- children between the ages of 5 - 15
T or F: Aschoff bodies and Anitskow cells are specific for post-rheumatic carditis.
- false!
- Aschoff bodies ARE, but Anitskow cells are NOT
Aschoff Body
- an interstitial aggregate of macrophages and lymphocytes, with necrotic collagen, in an area of interstitial fibrosis
Anitskow Cell
- cells with linear condensation of nuclear chromatin
- resembles a caterpillar
Which organism is associated with Rheumatic Fever?
- Strep. pyogenes
- (remember, rheumatic fever follows pharyngitis)
