Endocarditis is inflammation of the inner lining of the heart (endocardium) and may include involvement of the heart valves. This condition may be due to infectious or noninfectious causes, the former of which is more common. Regardless of its etiology, endocarditis requires prompt management to prevent serious consequences.
Infective Endocarditis
Infective endocarditis commonly involves bacteria, such as Staphylococcus aureus, Streptococcus species, and Pseudomonas aeruginosa. This often occurs because of a medical procedure or other action that introduces bacteria into the bloodstream. Examples include intravenous drug use, dental extractions, transurethral resection of the prostate, and endoscopic procedures. Once bacteria reaches the heart, they cling to the endocardium and/or heart valves. Platelets and fibrin aggregate around the bacteria, forming a mass called a vegetation, which can potentially break off, leave the heart, and lodge itself in another part of the body's circulatory system (embolize).
Patients with endocarditis may report various nonspecific symptoms, such as fever, loss of appetite, muscle pain (myalgia), and/or abdominal pain. When endocarditis affects the heart valves, a physician may detect an abnormal heart murmur due to altered blood flow through the valve. Other signs of endocarditis may appear outside of the heart, such as small linear hemorrhages in the fingernails (splinter hemorrhages), painful bumps in the hands and feet (Osler nodes), painless red spots in the hands (Janeway lesions), retinal hemorrhages (Roth spots).
Diagnosis of infective endocarditis primarily requires two tests. One is blood culture to identify the specific bacteria involved. The other is echocardiography to visualize the vegetations, which can be performed on the surface of the chest (transthoracic echocardiography, or TTE) or down the esophagus behind the heart (transesophageal echocardiography, or TEE). TTE is less invasive, but TEE can provide a clearer picture if TTE fails to visualize active endocarditis.
Antibiotics are the mainstay treatment of infective endocarditis. Depending on the effects of endocarditis on cardiac function, the extent of heart valve involvement, and the potential for embolism of the vegetation, surgery may also be necessary.
Noninfective Endocarditis
Noninfective endocarditis does not involve infectious pathogens. On the contrary, this type of endocarditis is the result of mechanical trauma from cardiac catheters during invasive cardiac procedures and/or various autoimmune conditions, such as systemic lupus erythematosus and antiphospholipid syndrome. Vegetations can still form, but they are sterile and devoid of pathogens.
Symptoms and signs of noninfective endocarditis are usually due to vegetation embolizing to another organ. Nonspecific clinical manifestations and heart murmurs occur less frequently than in infective endocarditis. Diagnosis requires visualization by echocardiography and a negative blood culture, and treatment generally involves addressing the underlying cause, if possible.
