Complications of infective endocarditis (IE) include cardiac, neurologic, renal, musculoskeletal, and pulmonary complications as well as complications related to systemic infection (including embolization, metastatic infection, and mycotic aneurysm). More than one complication can occur simultaneously.
Cardiac complications include heart failure, perivalvular abscess, pericarditis, and intracardiac fistula. Heart failure is the most common indication for cardiac surgery in patients with IE and is the most common cause of death.
Forms of metastatic infection include septic embolization, metastatic abscess, and mycotic aneurysm. Septic emboli can occlude or damage virtually any vessel in the systemic or pulmonary arterial circulation. Metastatic abscess can develop as a sequela of septic embolization; this may occur in the spleen, kidneys, brain, soft tissues, and/or lungs. Mycotic aneurysm can develop in the cerebral or systemic circulation in the setting of IE, usually at points of vessel bifurcation.
Neurologic complications include stroke, brain abscess, meningitis, and other manifestations; these can be the presenting symptom in patients with IE.
Renal complications of IE include renal infarction or abscess following septic embolization, glomerulonephritis (due to deposition of immunoglobulins and complement in the glomerular membrane), and drug-induced acute interstitial nephritis.
Musculoskeletal complications of IE include vertebral osteomyelitis and septic arthritis. Back pain in patients with IE should prompt consideration of vertebral osteomyelitis, particularly in the setting of S. aureus infection. Clues to the presence of septic arthritis in the setting of IE include involvement of multiple joints and involvement of the axial skeleton (eg, sacroiliac, pubic, or manubriosternal joints).
The six-month mortality rate among patients with IE ranges up to 27 percent. A number of factors appear to confer increased risk of mortality, including microbiology, heart failure, embolization, and candidacy for cardiac surgery.
