A case of infective endocarditis: TUTORIAL WITH MONICA CHAN

Mr Yong CW, a 37 yo Chinese gentleman with known VSD diagnosed incidentally by 2DE presented with:
1. Fever w/ chills and rigors
2. SOB
3. Cough (dry cough)

Negatives:
1. night sweat
2. history of IVDA, lines, recent dental procedures, antibiotic prophylaxis

O/E: Theoratical
Hands:
1. Janeway lesions (palm, MP, painless)
2. Oslers (Pulp, violaceous, painful)
3. splinter hemorrhages
4. clubbing (subacute infective endocarditis)

Arms:
1. injection marks, lines, tracts

Mouth:
1. oral hygiene

Chest:
1. pneumonia
2. signs of heart failure. Murmurs (changing heart murmurs!)

Abdo:
1. HSM (mild, due to seeding?)

Investigations: (my part) - Lab and imaging studies + others
Biochemical + bloods:
1. Septic W/u with FBC + Blood Cx (3x looking for continous bacteraemia)
2. U/E/Cr
3. LFT
4. Dipstix, UFEME (microscopic haematuria)

Imaging:
1. CXR
2. Serial ECG, looking for PR interval changes)

Thus this patient was managed as per infective endocarditions:
1. DO BLOOD CULTURE BEFORE ANTIBIOTIC THERAPY

EVERTHING ELSE BELOW IS HYPOTHETICAL BECAUSE BLOOD CULTURES ARE NOT BACK YET

Some generalizations:
1. IVDA usually Gram +ve (SA) KIV CAMRSA
2. Native valve: cover SA, Strep and Gram -ve
3. periop/new prosthetic valves: MRSA and cogulase -ve SA

While waiting for blood culture to be back:
EMPIRCAL TREATMENT:

1. native valves: Cover Gram +ve (SA and strep) and Gram -ve
Cloxacillin against SA (poor cover against Strep)
Penicllin against Strep (poor cover against SA)
Gentimicin (gram -ve cover + synergistic effect of shortening bacteraemia)

GloxPenGent

2. Perioperative: MRSA and coagulase -ve staph:
- Vancomycin + gentamicin (cloxacillin cannot cover MRSA)

if IVDA, R sided without pulmonary involvement: 2 weeks
if everything else, 4 weeks

After the cultures return: a more targetted approach:
1. Staph aureus:
- IV cloxacillin (4 weeks) + gentamicin (3-5d to decrease bacteraemia)

2. L sided endocarditis: streptococcus viridans: tend to be sensitive to penicillin but need to look out for MIC :
- Benzylpenicillin high dose for 4 weeks
- low dose Genta for 2 weeks

3. Prosthetic valves perioperatively:
- Vanco: 4-6 weeks
- genta 4-6 weeks
monitor kidney function

MO:
1. Blood Cx
2. empircal treatment
3. blood cx result returns
4. specific treatment
5. blood culture repeat on D2
6. f/u 2DE/TEE

Offer surgical Mx if:
1. abscess
2. involves aortic root
3. valve rupture
4. continuing embolic phenomenon despite ABx
5. continuing bacteraemia despite Abx
6. vegetation >1cm

Bacterial agents of Infective Endocarditis:
1. IVDA: staphylococcal aureus
2. Dental procedure: strept viridaans (alpha hemolytic?), HACEK (hemophilus, actinobacillus, cardiobacterium, eikenella, kingella)
3. Early Prosthetic valves: MRSA, coagulase -ve (staph epidermidis)
4. Late prosthetic valves: Strep viridans
5. Strep bovis (gamma hemolytic?)
6. enterococcus

DUKES CRITERIA FOR ENDOCARDITIS:
2 major, 1 major 3 minor, 5 minor

Major criteria (3 in all)
1. Histopathological evidence of thrombus (not applicable. post op)
2. TEE echo: new oscillatory lesion/thrombus on valve or new prosthetic valve dehiscence
3. Blood Cx +ve for viridans, SA, HACEK on 2x blood Cx 12 hours apart

Minor criteria (5 in all)
1. fever
2. immunologic response (janeway/osler)
3. embolisation evidence (splenomegaly eg.)
4. TEE not fulfilling major
5. blood Cx not fulfilling major