Heart & Stroke Conditions Explained



Endocarditis is a rare but potentially serious infection affecting the inner lining of the heart (endocardium) and most commonly affecting one of the heart valves.

It is usually caused by bacteria (germs) entering the blood and travelling to the heart. Endocarditis is more common in older people, people with damaged heart valves, artificial heart valves or other heart defects.



Symptoms of endocarditis can be very subtle and non-specific and can develop slowly over weeks or months (sub-acute), or can develop very quickly (acute) over a few days, rapidly getting worse.

Signs and symptoms may vary, but the most common include:

  • Flu like symptoms
    • With a high temperature and chills
    • Fatigue and tiredness
    • Aching joints and muscles
    • Headache
  • Persistent cough and sore throat
  • Unexplained weight loss
  • Shortness of breath
  • A new or changed heart murmur (heart sounds made by blood rushing through your heart)

Less common symptoms include:

  • Spotted red or purple rash on the skin (known as petechiae)
  • Narrow lines of blood under the fingernails

If you have been told you are at risk of getting endocarditis and have flu-like symptoms with a high temperature, you should not delay in contacting your doctor.



Endocarditis is most commonly caused by bacteria (germs), which are usually harmless, entering your blood and travelling to your heart.

Normally your heart is well protected by your immune system, but if your heart valves are damaged or you have artificial replacement valves or implanted heart devices (like pacemaker or ICD), it can be easier for these germs to cause an infection.

If you have already had an episode of endocarditis you are at a higher risk of developing future heart infections. Intravenous drug users are also at a higher risk.

Bacteria can enter your blood in the following way:

Mouth: If your teeth and gums are in bad condition, it makes it easier for bacteria to enter the bloodstream even with just brushing.

Infection:  If you already have an infection, such as a skin infection or a gum infection, it can spread more easily. It can also spread from a sexually transmitted infection (STI), such as chlamydia or gonorrhoea.

Catheters (tubes) and needles:  Where instruments are placed into the body for medical procedures, such as to inject or drain fluid from the body, there is a small risk infection can be introduced.  Contaminated needles used by intravenous drug users have the same risk.



If you have a healthy heart you are unlikely to develop this infection.

However, if you are at a higher risk because of damaged heart valves, artificial replaced valves or congenital heart defects, it is important to take precautions to protect yourself from infection.

Similarly, if you have previously had an episode of endocarditis, you should take the same precautions as this condition can often reoccur in some people.

To help you prevent endocarditis the following are recommended:

Good dental hygiene.

Watch out for abscesses and gum disease, have regular checkups with your dentist and get treated promptly.

Take care of your skin.

Keep any cuts or grazes clean and seek medical advice if you do develop a skin infection or if any cuts or scars are not healing properly.

Avoid body piercing or tattoos which involve breaking the skin and can lead to infection.

The use of antibiotics in prevention

Research has found that antibiotics are no longer recommended for all routine dental procedures as germs can become resistant each time they are used.

Antibiotics should only be used when absolutely necessary. They are prescribed for certain procedures including certain dental and medical procedures which could allow germs to enter the bloodstream, and should be discussed with your doctor and dentist.




Your doctor will start by taking your medical history and may be able to tell from your risk factors, your medical history and your description of your signs and symptoms.

There are some tests which may help the doctor make a diagnosis which may include an electrocardiogram (ECG); echocardiogram (ECHO); chest x-ray; blood tests to look for signs of infection.



Depending on the severity, most cases are treated with a course of antibiotics for 2 – 6 weeks.

You usually have to be admitted to hospital initially, as you may need high doses of antibiotic, given intravenously (through a vein in your arm).

Before starting an antibiotic, blood tests will be taken to identify the bacteria (germ) causing the infection, so that the most appropriate antibiotic, specific to that bacteria can be prescribed. While in hospital, regular blood tests will measure the effectiveness of the treatment.

When your signs and symptoms improve, you may be discharged and continue the antibiotics at home. If you are taking antibiotics at home, you will need to see your GP regularly to check that the treatment is working and that you are not having any side effects.

If the infection damages your heart valves this can be serious and you may need surgery to repair or replace the damaged valve.

Support for You


The Irish Heart Foundation offers a range of free support services to those affected by heart disease or stroke that can greatly improve their quality of life. These include support groups, physical exercise classes, therapy sessions and more.

For more information on these supports, see our Patient Supports page.



Read our resources for further information:

Have a look at our selection of Ways To Live Life Better articles that cover everything from healthy eating, to being active, reducing alcohol and salt, and quitting smoking.



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