Bacterial endocarditis is an infection of the endocardial surface of the heart. The most common structures of the heart affected are the heart valves. Both native and prosthetic valves can be affected. Historically, the term "acute" endocarditis was used to describe the rapidity of symptoms, as opposed to "subacute" endocarditis. However, these terms have fallen out of favor as it is well known that there is significant overlap in presentation. A more helpful description is to use the name of the pathogen causing endocarditis (eg, a physician might say "native aortic valve endocarditis due to Staphylococcus aureus").

Patients at increased risk of this infection include intravenous drug users and patients with a predisposing heart condition including the presence of cardiac devices or prosthetic cardiac valves. Infection, including Candida infection, can occur after open heart surgery or valve replacement via catheter (TAVR).

Clinically, the patient may appear acutely ill, chronically ill and wasted, or in rare cases, the patient may be fairly asymptomatic. Patients typically have fever. Cardiac murmur is usually present. On physical examination, there may be conjunctival hemorrhages, splinter hemorrhages, Janeway lesions (nontender hemorrhagic macules and papules on the palms), Osler nodes (painful erythematous nodules located on the fingertips), or Roth spots (pale lesions with surrounding hemorrhage seen in the fundi, with an ivory or white center surrounded by a red halo). Palpable purpura may also be seen.

Imaging may reveal septic pulmonary infarcts, mycotic aneurysms, and stroke. Laboratory testing may reveal anemia, leukocytosis, elevated ESR, positive rheumatoid factor, hematuria, and red blood cell (RBC) casts in urine.

The diagnosis of endocarditis can be made by isolating the responsible organism in blood culture and by visualizing the vegetation on echocardiography. Treatment is with prolonged antibiotics and sometimes with surgery to remove the source of infection.