Endocarditis

Today we discussed endocarditis. This is a very important topic to have knowledge of regardless of what area one practices in, both in terms of suspecting and confirming the diagnosis, and proper management. The natural history of untreated endocarditis is 100% mortality. A few points:

Traditional breakdown is by time course; perhaps less relevant today than previously.

Subacute classically presents as a chronic, wasting illness, with fever, wt loss and progressive heart failure and complications as the heart is progressively damaged over weeks to months. Typical organisms are (in order) viridans group streptococci, enterococcus, st. aureus

Acute presents with rapidly progressive valvular destruction over days, often with catastrophic hemodynamic and other complications. Typical organisms are st. aureus, enterococci, viridans group streptococci, HACEK organisms.

Other useful classifications that help with predicting microbiology and complications are native vs. prosthetic valve and R-sided vs. L-sided.

Some physical findings (not exhaustive!)

Signs of valvular involvement or local complications:
-murmurs (esp. AI, MR, TR)
-signs of L or R-sided heart failure
-bradycardia (heart block can occur from paravalvular abscess)

Signs of embolic complications/phenomena and vasculitis
-any focal neurological deficit-peripheral cutaneous signs: Splinter hemorrhages, Osler nodes, Janeway lesions, Roth spots, clubbing, subconjuntival and other mucosal petechiae. Remember to look for these on the feet too
-splenomegaly

Signs of underlying causes
-track marks for IDU
-oral exam for dental hygiene

Diagnosis:
-multiple blood cultures from different sites off antibiotics are KEY to the diagnosis and management

Modified Duke's criteria can be helpful (see link for full details):

Major

-multiple blood cultures consistent or Q-fever serology +ve
-echo consistent (oscillating mass, abscess, dehiscence of prosthesis)
-new murmur

Minor
-predisposing heart condition or IVDU
-fever
-vascular phenomena (emboli, etc as above)
-immunologic phenomena (as above)
-blood cultures not meeting criteria for "major"

Definite: (2 major) or (1 major+3 minor) or (5 minor)
Possible: (1 major and 1 minor) or (3 minor)

ECG- check for new blocks (esp. 1st degree AVB; suggests abscess)

Therapy
General principles- need cidal antibiotic. Generally need minimum 4-6 wks of IV therapy

Indications for valve replacement (NB- surgery is probably under-utilized)
-CHF as a direct consequence
-Severe valvular insufficiency
-Paravalvular abscess
-Embolic phenomena post-initiation of therapy
-Persistently positive cultures or fever despite adequate medical therapy
-Size of vegetation (relative)

Links:

Click here for the complete modified Duke's criteria

Click here for a review article from NEJM