Acute or Subacute Bacterial Endocarditis is an infection of the heart’s endocardium. The endocardium is the inner lining of the heart muscle, which also covers the heart valves. Bacterial Endocarditis can damage or even destroy your heart valves. The difference between acute and subacute bacterial endocarditis is acute bacterial endocarditis is a sudden onset, whereas subacute bacterial endocarditis is a gradual onset.
Acute endocarditis most often occurs when an aggressive species of skin bacteria, especially a staphylococcus (staph), enters the bloodstream and attacks a normal, undamaged heart valve. Once staph bacteria begin to multiply inside the heart, they may send small clumps of bacteria called septic emboli into the bloodstream to spread the infection to other organs, especially to the kidneys, lungs and brain. Intravenous (IV) drug users are at very high risk of acute endocarditis, because numerous needle punctures give aggressive staph bacteria many opportunities to enter the blood.If untreated, this form of endocarditis can be fatal in less than six weeks.
Subacute endocarditis is caused by one of the viridans group of streptococci (Streptococcus sanguis, mutans, mitis or milleri) that normally live in the mouth and throat. Streptococcus bovis or Streptococcus equinus also can cause subacute endocarditis, typically in patients who have some form of gastrointestinal cancer, usually colon cancer. Subacute endocarditis tends to involve heart valves that already are damaged in some way, and it usually is less likely to cause septic emboli than acute endocarditis. If untreated, subacute bacterial endocarditis can worsen for as long as one year before it is fatal.
Acute: no previous heart valve damage
- S. aureus (for non IVDA and IVDA)
Subacute: previous heart valve damage
- Viridans group: S.mutans, S.sanguis; with hx of dental work without prophylaxis.
- Group D strep: S. bovis, Enterococcus; with hx of GI or GU qx without prophylaxis
- S. epidermidis, Candida, Aspergillus, Pseudomona, Viridans group: IVDA
Dx: Dukes criteria