Microbiology of Infectious Endocarditis

Question 1

How serious is infective endocarditis?

Answer 1

life threateningly serious

Question 2

What 2 microorganisms account for 80% of all cases of infectious endocarditis?

Answer 2

Staph and Strep

Question 3

What microorganism causes Rheumatic heart disease?

Answer 3

Strep pyogenes (group A strep)= gram (+) cocci in chains

Question 4

What can help make the diagnosis of infective endocarditis?

Answer 4

petechiae on buccal mucosa and/or extremities

not always present though

Question 5

Where is infective endocarditis a big problem due to rheumatic heart disease?

Answer 5

India, southeast Asia, and central Africa.

Question 6

What will strep pyogenes do to the epithelial cells of the pharynx?

Answer 6

disorganizes them, increasing likelihood of antibodies cross-reacting with collagen, leading to rheumatic heart disease.

Question 7

What is the most common heart valve affected in RHEUMATIC fever (not endocarditis per say)?

Answer 7

mitral valve

Question 8

What are the symptoms of rheumatic fever?

Answer 8

fever, polyarthritis (arthritis that jumps to different joints), carditis, chorea (uncontrolled movements), erythema marginatum (rash), subcutaneous nodules

Question 9

Is rheumatic heart disease a disease of poverty?

Answer 9

YES

Question 10

How long does rheumatic fever take to present following strep throat?

Answer 10

3 weeks

Question 11

What is the progression of group A strep?

Answer 11

• primordial prevention = improving social determinants of health
• primary= Rx initial infections
• secondary= antibiotic prophylaxis following acute rheumatic fever
• tertiary= med/surg management of rheumatic heart disease

Question 12

What is the saying for group A strep’s role in RHD?

Answer 12

“it licks the joints but bites the heart”

Question 13

**What bacteria is the most common bacteria that causes infective endocarditis in IVDU?

Answer 13

Staph aureus and this goes to the RIGHT side of the heart (due to venous drainage).

Question 14

What are some peripheral manifestations of IE (not RHD, but this may result DUE to RHD)?

Answer 14

• splinter hemorrhages in the nail beds
• Osler nodes (tender) on the digits. “O= OUCH”
• Janeway lesions (nontender)
• conjunctival petechiae
• Roth spots (seen on the retina)

Question 15

Is strep viridans alpha or beta hemolytic strep?

Answer 15

VIRIDANS= alpha hemolytic.

Question 16

How do you test for clubbing of the fingers?

Answer 16

but the two thumbs nails together and look for a diamond shape. If the space is not there, then there is clubbing of the fingers (Schamroth’s sign).

Question 17

What would nail beds look like with iron deficiency?

Answer 17

Koilonychia= concavity of the nail

Question 18

What is Quincke’s pulse?

Answer 18

alternate flushing and blanching of nail beds in concert with cardiac cycle (sever/chronic aortic insufficiency).

Question 19

What is the first thing you should do if you suspect IE?

Answer 19

get a TTE

Question 20

What is a vegetation on a valve?

Answer 20

a dense aggregate of microorganisms, platelet-rich thrombus, and inflammatory leukocytes.

Question 21

What is the link associated with strep bovis?

Answer 21

colon cancer

Question 22

**What are the HACEK organisms associated with ID?

Answer 22

Haemophilus
Actinobacillus
Cardiobacterium
Eikenella
Kingella

Question 23

**What are some classic culture-negative IE pathogens?

Answer 23

• Bartonella henselae
• Coxiella burnetti (Q fever)
• Tropheryma whipplei

Question 24

When is prophylaxis recommended?

Answer 24

only in those with prostehtic cardiac valves, previous IE, or CHD.

Question 25

**What is the most common cause of acquired heart disease in children in the developed world?

Answer 25

Kawasaki disease