infective endocarditis

Infective endocarditis is an infection of the heart's inner lining, the endocardium, most often settling on the heart valves. When microbes circulating in the blood land on a valve surface, they can stick, multiply, and build up an infected lump of organisms and clot called a vegetation, rather like barnacles fouling the moving flap of a hull.

Bacteria are the usual culprits, especially streptococci, staphylococci, and enterococci, though fungi occasionally cause it. Risk is higher when valves are already abnormal, when an artificial valve or device is present, or when bacteria are introduced through intravenous drug use, dental or surgical procedures, or long-term catheters. The infection both destroys valve tissue, causing leakage, and sheds infected fragments that travel through the bloodstream.

The illness can be acute and fulminant or smouldering over weeks. Features include fever, a new or changing heart murmur, and embolic phenomena such as strokes, splinter haemorrhages under the nails, and small painful nodules. Diagnosis rests on blood cultures and echocardiography, and treatment requires prolonged intravenous antibiotics, sometimes with surgery to repair or replace a destroyed valve.