Approach to diagnosis and management
Clinical Criteria :
Diagnosis is straight forward in those patients with classic manifestations bacteremia or fungemia or evidence of acitve valculitis, peripheral embolic phenomenon etc. In others however classic peripheral stigmata may be few or absent, especially during acute courses of Infective Endocarditis, particularly among intra venous drug abusers, infective endocarditis caused by micro organisms such as HACEK. Immunological vascular phenomenon are more characteristic of subacute infective endocarditis, as acute infective endocarditis evolves too quickly for development of immunological vascular phenomenon.
I. Definite infective endocarditis : Two major criteria or one major and three minor criteria or five minor criteria.

A. Major criteria
1. Isolation of viridans streptococci, S. bovis, HACEK group organisms, or (in the absence of a primary focus) community acquired S. aureus or Enterococcus from two separate
blood cultures or isolation of a microorganism consistent with endocarditis in (a) blood
cultures > 12h apart or all of the three or most of four or more blood culture, with first
and last at least 1h apart.
2. Evidence of endocardial involvement on echocardiography oscillating intracardiac mass or abscess or new partial dehiscence of prosthetic valve or new valvular regurgitation.

B. Minor criteria
1. Predisposing lesion or intravenous drug use
2. Fever or > 38.0o C
3. Major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages Janeway lesions.
4. Glomerulonephritis, Osler’s nodes. Roth’s sports, rheumatoid factor.
5. Positive blood cultures not meeting the major criterion (excluding single cultures positive for organisms that do not typically cause endocarditis) or serologic evidence of active
infection organism that causes endocarditis.
6. Echocardiogram consistent with endocarditis but not meeting the major criterion.
II. Possible infective endocarditis : Findings that fall short of "definite" but do not fall into the "rejected" category.
III. Rejected : Alternative diagnosis or resolution of syndrome or no evidence of infective endocarditis at surgery or autopsy with < 4 days.

Echocardiogram:
Plays an important role in the diagnosis and management of Infective Endocarditis. Characteristic vegetations, abscess, new prosthetic valve dehiscence, or new regurgitation are four powerful identifiers of Infective Endocarditis in combination with other clinical parameters.

Complications
1. Embolic episodes
2. Mycotic aneurysms and rupture (10%)
3. Metastatic abscesses
4. Heart failure
5. Myocardial abscesses
6. Renal disease
-renal emboli
- immune complexes glomerulonephritis
- renal failure

Laboratory manifestations
Anemia - 70-90%
Leukocytosis - 20-30%
Proteinuria - 50-65%
Microscopic hematuria - 30-50%
Increased serum
creatinine level - 10-20%
Increased ESR - > 90%
RA factor - 50%
Circulating immune
complexes - 65-100%
Decreased serum
complement level - 5-40%