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Infective endocarditis

Endocarditis is an infection in the tissue lining your heart chambers. This can lead to heart valve problems. Find out what you can do to protect your heart if you are at risk of infective endocarditis.

Infective endocarditis is a serious infection of the endocardium - the tissue that lines the inside of the heart chambers. The infection usually involves one or more heart valves which are part of the endocardium.

To develop this infection you need to have some bacteria or fungi in the bloodstream. This can be from an infection or wound in another part of the body. A small number of cases are caused by infection with fungi although most cases are caused by infection with bacteria. 

In time, small clumps of material called vegetations may develop on infected valves. The vegetations contain bacteria or fungi, small blood clots, and other 'debris' from the infection. The vegetations may prevent affected valves from opening and closing properly. The infection can also damage affected valves, and may spread to other areas of the endocardium or heart tissue. Fragments of the vegetations may also break off and travel in the bloodstream to other parts of the body.

Preventing infective endocarditis

Good oral and dental hygiene is thought to be important in preventing infective endocarditis. In particular, if you have any condition which increases your risk of developing infective endocarditis, then, don't let any dental problems such as a dental abscess or gum disease go untreated. These dental conditions increase the chance of bacteria getting into the bloodstream.

People with an increased risk of developing infective endocarditis might be advised to take a short course of antibiotics before certain dental procedures. It’s thought that some procedures might 'push' bacteria into the bloodstream and that antibiotic cover would kill bacteria that get into the blood, before they settle on the endocardium or heart valves. Your doctor or dentist will advise whether or not you need to take antibiotics before you have a dental procedure.

Some conditions put you at more risk of developing infective endocarditis, including:

  • Prosthetic heart valves (biological or mechanical)
  • Rheumatic valvular heart disease
  • Previous endocarditis
  • Unrepaired cyanotic congenital heart disease (includes palliative shunts and conduits)
  • Surgical or catheter repair of congenital heart disease within 6 months of repair procedure.

Most bacteria that get into the bloodstream are killed by the immune system. However, sometimes some bacteria survive and settle on a heart valve (particularly if the valve is already damaged in some way), or on another section of the lining of the heart (endocardium). Once infection develops in the endocardium, it is difficult for the immune system to clear it.

Symptoms can include:

  • A slowly developing infection
  • Feeling generally unwell. You may have have aches and pains, tiredness, and not have much of an appetite
  • A fever (a high temperature) develops at some stage in most cases.

As these first symptoms can be caused by a lot of other conditions, infective endocarditis may not be diagnosed for some time.

You may also develop a heart murmur. This is a sound that can be heard by a doctor listening to your heart with a stethoscope. Murmurs are caused by abnormal flow of blood through faulty or damaged valves. If you already have a heart murmur from an existing valve problem, the murmur may change or become more intense. A new or changing murmur is often what alerts a doctor to suspect infective endocarditis.

You will be admitted to hospital if infective endocarditis is suspected. You will have several blood samples taken which are tested for bacteria and fungi. If any bacteria are detected in the blood, they are tested against various antibiotics to find which is the best one to use. Some bacteria are resistant to some antibiotics. Therefore, the best antibiotic to use can vary from case to case.

An ultrasound scan of the heart called an echocardiogram is the most useful test to confirm infective endocarditis. It can detect vegetations, and look for damage to heart valves and other heart structures. Various other tests or scans may be done to find out the extent of the infection, and to assess the damage to the heart or other affected organs.

Infective endocarditis can be managed in two ways, intravenous medications or surgery. Most people require intravenous and then oral antibiotics for a period of time. Some people need to go on to have heart valve surgery. 

Note: If you have had rheumatic fever, valve surgery or previous endocarditis you need to let your dentist know before having dental procedures or operations. This is because you may need need extra antibiotics to help protect your heart from further infection. 

Learn about heart valve problems