Infective Endocarditis & Valve Disease

Question 1

State at least 4 causes of infective endocarditis

Answer 1

Poor dental hygiene, IVDU, soft tissue infection, dental treatments, IV cannulae/lines, cardiac surgery inc pacemakers - all lead to bacteraemia

Question 2

State 2 pathogens that cause acute infective endocarditis

Answer 2

Staphylococcus aureus, Streptococcus pyogenes

Question 3

State at least 5 pathogens that cause subacute infective endocarditis

Answer 3

Streptococcus viridans, Staphylococcus epidermis, Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella, Coxiella, Mycoplasma, Candida

Question 4

Where does acute endocarditis usually spread?

Answer 4

Aorta

Question 5

Where does subacute endocarditis usually spread?

Answer 5

Chordae (thick, strong, tendinous connections between the mitral valve cusps and the papillary muscles, also known as heart strings)

Question 6

Describe the clinical features of infective endocarditis

Answer 6

Constitutional: fever, malaise, rigors, anaemia
Cardiac: new murmur, usually MR
Immune: Roth spots, Osler’s nodes, glomerulonephritis -> haematuria
Thromboembolic: Janeway lesions, septic abscesses (in lungs, brain, spleen, or kidney), microemboli, splinter haemorrhages, splenomegaly

Question 7

Which group of patients typically get right-sided infective endocarditis?

Answer 7

IV drug users

Question 8

Which criteria are used to diagnose infective endocarditis?

Answer 8

Duke criteria - 2 major, or 1 major + 3 minor, or 5 minor

Question 9

State the two major criteria for diagnosing infective endocarditis

Answer 9

Positive blood culture growing typical infective endocarditis organisms OR two positive cultures of atypicals >12h apart
Evidence of vegetation or abscess on echocardiogram or new regurgitant murmur

Question 10

State the five minor criteria for diagnosing infective endocarditis

Answer 10

Risk factor (e.g. prosthetic valve, IVDU, congenital valve abnormalities), fever >38, thromboembolic phenomena, immune phenomena, positive blood cultures not meeting major criteria

Question 11

How is subacute endocarditis usually treated?

Answer 11

Depending on cause. Example regime benzylpenicillin + gentamicin for 4 weeks, or vancomycin for 4 weeks

Question 12

How is acute endocarditis treated?

Answer 12

Flucocloxacillin

If MRSA, rifampicin + vancomycin + gentamicin

Question 13

Describe the pathophysiology of aortic stenosis

Answer 13

Narrowed aortic valve causes high velocity, high pressure flow

Question 14

Describe the pathophysiology of aortic regurgitation

Answer 14

Incompetent aortic valve allows blood flow back into the left ventricle after systole

Question 15

Describe the pathophysiology of mitral stenosis

Answer 15

Narrowed mitral valve causes high velocity, high pressure flow. Back pressure leads to left atrial dilatation

Question 16

Describe the pathophysiology of mitral regurgitation

Answer 16

Incompetent mitral valve allows blood flow back into the left atrium during systole

Question 17

State two causes of aortic stenosis

Answer 17

Calcification with age, congenital bicuspid valve

Question 18

State at least three causes of aortic regurgitation

Answer 18

Infective endocarditis, dissecting aortic aneurysm, left ventricular dilatation, connective tissue disease (e.g. Marfan, ankylosing spondylitis)

Question 19

State the main cause of mitral stenosis

Answer 19

Rheumatic fever

Question 20

State at least three causes of mitral regurgitation

Answer 20

Infective endocarditis, connective tissue disease, post-MI, rheumatic fever, left ventricular dilatation (functional MR)

Question 21

What is chronic rheumatic valve disease?

Answer 21

Thickening of the valve leaflet, especially along lines of close, and fusion of commissures post-rheumatic fever, with thickening, shortening, and fusion of chorea tendineae. Mainly affects mitral valve, sometimes aortic, rarely tricuspid, almost never pulmonary.

Question 22

Describe the typical presentation of mitral valve prolapse

Answer 22

Middle-aged woman with shortness of breath and chest pains. On examination, mid systolic click and late systolic murmur

Question 23

State the five types of pericarditis, and a cause of each

Answer 23

Fibrinous (MI, uraemia), purulent (Staph), granulomatous (TB), haemorrhagic (tumour, TB, uraemia), fibrous/ constrictive (any cause of pericarditis)

Question 24

What is the most common cause of pericardial effusion?

Answer 24

Chronic heart failure