Endocarditis is caused by bacteriain the bloodstream multiplying and spreading across the inner lining of your heart (endocardium). The endocardium becomes inflamed, causing damage to your heart valves.
Your heart is usually well protected against infectionso bacteria can pass harmlessly by. However, if your heart valves are damaged or you have an artificial valve, it's easier for bacteria to take root and bypass your normal immune response to infection.
Small clumps of bacteriacan develop at the site of the infection. There's a risk of these clumps acting ina similar way to Arterial thrombosis , travelling away from the heart and blocking the blood supply to the organs. This can cause organ failure or trigger a stroke .
The most common ways that bacteria can enter your blood are explained below.
Everyday activities, such as brushing your teeth or chewing your food, can sometimes allow bacteria to enter the bloodstream. The risk is increased if your teeth and gums are in bad condition, because it makes it easier for bacteria to enter.
Bacteria can spread from the site of a pre-existing infection, such as a skin infection or a gum infection .
Bacteria can also enter your body as a result of a sexually transmitted infection (STI) , such as chlamydia or gonorrhoea .
Any medical procedure that involves placing a medical instrument inside the body carries a small associated risk of introducing bacteria into your bloodstream.
Instruments that have been linked to endocarditis include:
There are a number of things that can make your heart more vulnerable to infection and increase your chances of developing endocarditis. These are discussed below.
Heart valve disease is a general term describing conditions that damage the valves of the heart. Two types of heart valve disease known to increase your risk of endocarditis are:
Heart valve disease can be either:
Causes of acquired heart valve disease include:
Rheumatic fever is raresince theintroduction of antibiotics. However, older people who had rheumatic fever during childhood may go on to develop heart valve disease.
Prosthetic (artificial) valves are used to replace heart valves that have beendamaged by heart valve disease.
However, bacteria can also take root around prosthetic valves, which can occasionally trigger endocarditis. This risk is relatively low,estimated to be less than one in 100.
In hypertrophic cardiomyopathy , the heart muscle cells have enlarged and the walls of the heart chambers thicken. The chambers are reduced in size so they can't hold much blood, and the walls can't relax properly and may stiffen.
Hypertrophic cardiomyopathy is thought to affect 1 in 500 people in the UK.
People who habitually inject illegal drugs such as heroin or methamphetamine (crystal meth)into their veinshave an increased risk of developing endocarditis.
This is because unsterilised needles allow bacteria to enter the bloodstream and repeated injections make the skin more vulnerable to infection.
Endocarditis caused by a fungal infection is rarer than bacterial endocarditis, and usually more serious. You're more at risk of fungal endocarditis if you:
Endocarditis is a rare and potentially fatal type of heart infection. It's specifically an infection of the inner lining of the heart (the endocardium).
Common symptoms of endocarditis include a high temperature (fever), chills, loss of appetite and unexplained weight loss
If your heart valves are damaged, or if you have an artificial valve, it will be easier for bacteria to take root and trigger an infection.
To diagnose endocarditis, your GP will look closely at your medical history, paying particular attention to any problems that you may have had with your heart.
Most cases of endocarditis can be treated with a course of antibiotics though you may have to be admitted to hospital
If you have an increased risk of developing endocarditis, it is important that you limit your exposure to any infection that could trigger it.