Today’s intern morning report involved 93 year old woman who presented with altered mental status and syncope, found to have MRSA in her urine as well as blood and eventually diagnosed with MRSA endocarditis.
Important teach points regarding endocarditis:
-MRSA is NOT a usual organism found in the urine, even in the presence of an indwelling foley catheter. Anybody with staph aureus bacteriuria needs further work-up for another source, and bacteremia/endocarditis always needs to be evaluated.
-The sensitivity of TTE for detecting endocarditis is <80%, therefore if suspicion is high (especially in the case of MRSA bacteremia), a TEE is indicated.
Diagnosis of endocarditis is based upon the Duke criteria (2 major, 1 major + 3 minor or 5 minor):
Major- 1. Positive blood cultures (typical organism from 2 separate cultures or 3 cultures with a common skin contaminant organism) 2. Evidence of vegetation, abscess or prosthetic valve dehiscence or new valve regurgitation (change in murmur not sufficient)
Minor- 1. Risk factors (IVDU, prosthetic valve) 2. Fever ≥38 deg C 3. Vascular phenomena (septic emboli, pulmonary infarct, Janeway lesion, mycotic aneurysm) 4. Immunologic phenomena (+Rheumatoid factor, glomerulonephritis, osler nodes, roth spots) 5. Positive blood cultures not meeting major criteria or serologic evidence of infection
-Empiric therapy while awaiting cultures is vancomycin, gentamicin is not indicated. Rifampin can be added in the setting of prosthetic valve endocarditis.
For additional information, see the infective endocarditis handout, which is also posted under “Quick References”.
Thank you Edward Lin for teaching us all about endocarditis!