Valvular Disorders & Infective Endocarditis

Question 1

Which valve is most commonly affected?

Answer 1

• the mitral valve

Question 2

What is the most common cause of aortic stenosis?

Answer 2

• calcific aortic stenosis; calcified masses on the valvular cusps impede valve opening
• (there is NO fusion of the commissures here)

Question 3

What is the most common congenital valvular lesion?

Answer 3

• bicuspid aortic valve

Question 4

Mitral valve regurgitation is most commonly due to __________; mitral valve stenosis is most commonly due to ___________.

Answer 4

• regurgitation: myxomatous degeneration (floppy valve, ballooning of the leaflets)
• stenosis: rheumatic valvular disease (“fish mouth”)

Question 5

Rheumatic Heart Disease is cardiac inflammation via which organism? What is the pathology behind the disease?

Answer 5

• group A beta-hemolytic streptococci
• pathogenesis: the Ab produced against these bacteria also target the heart (bacterial M protein resembles human tissue: molecular mimicry)

Question 6

A patient with Rheumatic Heart Disease will often have had what a few weeks back?

Answer 6

• pharyngitis (1 - 3 weeks before)

- (the bacteria often invade the pharynx first before leading to the systemic rheumatic fever)

Question 7

Microbial invasion of the heart valves and endocardium (ie, the endocardium lining the valves) is known as:

Answer 7

• infective endocarditis

Question 8

Pathogens of Infective Endocarditis

Answer 8

• 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

Question 9

In Infective Endocarditis, what results in janeway lesions, splinter hemorrhages, and osler nodes?

Answer 9

• septic embolization

Question 10

HACEK Organisms

Answer 10

• organisms that can cause infective endocarditis, but result in NEGATIVE blood cultures

Question 11

Rheumatic Valvular Disease is a result of what? Which valves does it usually affect?

Answer 11

• 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)

Question 12

What do we see in Rheumatic Fever/Rheumatic Heart Disease?

Answer 12

• 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”

Question 13

On histology, what do we see in Rheumatic Heart Disease?

Answer 13

• Aschoff bodies with Anitskow (“caterpillar”) cells

- a result of inflammation of the myocardium

Question 14

Classic Triad of Symptoms for Aortic Stenosis

Answer 14

• chest pain, heart failure (dyspnea, PND), and syncope

Question 15

What murmur is associated with Aortic Stenosis?

Answer 15

• a pan-systolic crescendo-decrescendo mumur

Question 16

What is the key finding needed to diagnose Infective Endocarditis?

Answer 16

• bacteria in the blood-stream
• specifically, blood cultures persistently positive for one of these organisms, from cultures drawn more than 12 hours apart

Question 17

Infective Endocarditis most commonly affects the:

Answer 17

• mitral valve (aortic valve is the 2nd most common)

Question 18

Rheumatic Fever is most commonly seen in what demographic?

Answer 18

• children between the ages of 5 - 15

Question 19

T or F: Aschoff bodies and Anitskow cells are specific for post-rheumatic carditis.

Answer 19

• false!

- Aschoff bodies ARE, but Anitskow cells are NOT

Question 20

Aschoff Body

Answer 20

• an interstitial aggregate of macrophages and lymphocytes, with necrotic collagen, in an area of interstitial fibrosis

Question 21

Anitskow Cell

Answer 21

• cells with linear condensation of nuclear chromatin

- resembles a caterpillar

Question 22

Which organism is associated with Rheumatic Fever?

Answer 22

• Strep. pyogenes

- (remember, rheumatic fever follows pharyngitis)