Subacute infective endocarditis

Subacute infective endocarditis often occurs on the basis of rheumatic valvular heart disease, ventricular septal defect, patent ductus arteriosus, and other heart diseases, but can also occur in patients without prior heart disease. The main pathogens are bacteria, followed by fungi, rickettsiae, chlamydiae, and viruses. The main manifestations include low-to-moderate fever, progressive anemia, fatigue, night sweats, hepatosplenomegaly, and clubbing of fingers (toes); vascular embolism phenomena may occur. The disease is more common in young and middle-aged adults. In recent years, there has been an increasing trend of the disease occurring on the basis of mitral valve prolapse, cardiac catheterization and cardiac surgery, and degenerative valvular changes in the elderly, with a gradually increasing age of onset. Streptococcus viridans is the most important causative organism, but its incidence has significantly decreased in recent years; various staphylococci, hemolytic streptococci, enterococci, and Gram-negative bacilli have become the main pathogens.