What is endocarditis?

This infection of the heart’s inner lining is rare, but some people with heart conditions are at higher risk. Professor Jonathan Sandoe, Associate Clinical Professor in Microbiology at the University of Leeds and Honorary Consultant Microbiologist at Leeds Teaching Hospitals NHS Trust, explains more about the condition. 

A micrograph image of a heart valve with endocarditis. The heart valve tissue is infected with bacteria (shown in blue)

A micrograph image of a heart valve with endocarditis. The tissue is infected with bacteria (shown in blue)

How common is endocarditis?

It affects one in 30,000 people in the UK, which is about 2,000 diagnoses each year.

Who is at risk?

Your risk of endocarditis is increased by having:

If you have a problem with a valve or you have man-made materials in the heart, it is easier for bacteria to lodge there, and your body may not be able to fight off the infection. Intravenous drug users are at risk even if they don’t have heart problems.

What are the signs and symptoms?

The main symptoms of endocarditis are:

  • Feeling tired and awful
  • Appetite loss.
  • Flu-like symptoms which don't go away: flu symptoms tend to get better within 10 days, while endocarditis continues.
  • Shivers, shakes and night sweats (fever in the night, so sheets or nightclothes may be wet when you wake). This is an important symptom to tell your doctor about.

Always seek medical help urgently if you think you may have endocarditis. Early diagnosis makes treatment easier and more successful.

How is endocarditis diagnosed and treated?

Always seek medical help urgently if you think you may have endocarditis

Endocarditis can be difficult to diagnose. If you have symptoms, diagnosis would be confirmed with blood samples tested in the lab to find bacteria. An echocardiogram can show an abnormal bacterial growth on the valve. It is treated with intravenous antibiotics, usually for 4–6 weeks. Some people need valve surgery. If you have a device, it may be removed.

What are the long-term effects of endocarditis?

A lot of people with endocarditis need surgery, due to damage to the heart valves caused by the infection. There are potential complications including stroke. Infection can spread from the valve to places such as the joints or bones of the back, which may cause ongoing joint or back pain. One in five people die from endocarditis during a hospital stay.

Are there preventative antibiotics?

NICE recommends people should not usually be given antibiotics before a medical or dental procedure. This is because these procedures are no longer thought to be the main cause of endocarditis and taking antibiotics carries some risk. Preventative antibiotics are sometimes needed, and your doctor should discuss this with you.

How can patients who’ve had valve surgery reduce their risk?

Look after your teeth and see the dentist regularly. If the kind of bacteria that colonise teeth enter the bloodstream, they can cause endocarditis. Try to avoid injury or cuts, and keep these clean if you do get them to reduce risk of infection. 

Research into endocarditis

We’re trying to stop people suffering from endocarditis. Professor Jennifer Potts is a BHF Senior Research Fellow at the University of York. Her lab looks at the structure and function of proteins on the surface of bacteria and how these cause endocarditis. Her team is studying how bacteria are able to form antibiotic-resistant colonies on the surfaces of heart valves and devices such as pacemaker leads. If we understand this, we may be able to prevent endocarditis in future.

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