COVID-19 Information - To see our up to date advice for using our pharmacies - Click Here

Health Knowledge and Encyclopedia

At your local Pearn's Pharmacy we can offer advice on most general health matters. You can also use our Health Encyclopaedia to provide you with the tools and links you need to pinpoint symptoms and get a full explanation of a suspected condition.

Search By Letter
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y |

Search by Keyword



Endocarditis is a rare but serious condition where the inner lining of the heart becomes inflamed. This is usually as a result of a bacterial infection, but can, less commonly, be caused by a fungal infection.

Symptoms of endocarditis include flu-like symptoms such as a high temperature (fever) and chills, fatigue and a shortness of breath.

Endocarditis is a potentially serious condition because the inflammation (swelling) that occurs inside the heart can interrupt the normal blood flow through the heart valves. This can trigger a range of complications such as:

How common is endocarditis?

Endocarditis is a rare condition. In England and Wales for example, endocarditis is estimated to affect fewer than 10 people in every 100,000 in any given year. You are more likely to develop endocarditis in the following cases.

  • If you have a prosthetic (artificial) heart valve. Prosthetic heart valves are increasingly being used to treat a range of heart conditions, such as stenosis (where one of the valves of the heart narrows).
  • If you have congenital heart disease (CHD). Congenital heart disease is when a person is born with heart defects.
  • If you have previously experienced damaged to the valves of your heart, due to infection or heart disease.
  • If you are an intravenous (injecting) drug user. People who regularly inject themselves with heroin are three times more likely to develop endocarditis than the population at large.

Endocarditis is more common in older people, with half of all cases occurring in people who are over 50. However, cases of endocarditis have been recorded in children, particularly those who are born with congenital heart disease. Twice as many men are affected by endocarditis as women.

Endocarditis is regarded as a medical emergency and usually requires admission to an intensive care unit (ICU). Intravenous antibiotics are usually used to treat the underlying infection. Just under half of all people with endocarditis will require surgery to repair the damage to their heart.


Unfortunately, the outlook for endocarditis is not favourable. This is because the condition is life-threatening and is challenging to treat. An estimated one in five people with endocarditis will die as a result of complications that arise from the condition. In England and Wales, approximately 300 deaths are caused by endocarditis each year.

If you are at significant risk of developing endocarditis, it is important to take basic precautions to limit your exposure to harmful bacteria, for example, by brushing your teeth regularly. Some cases of endocarditis are triggered by poor dental hygiene after an infection in the mouth spreads to the heart via the blood. See the section on preventing endocarditis for more information.

^^ Back to top


There are two ways that the symptoms of endocarditis can develop:

  • over the course of a few days, rapidly getting worse (acute endocarditis)
  • slowly, over the course of a few weeks or possibly months (subacute endocarditis)

Subacute endocarditis is more common in people with congenital heart disease.

Common symptoms

The symptoms of endocarditis include:

  • a high temperature (fever) of 38°C (100.4°F) or above
  • chills
  • night sweats
  • muscle and joint pain
  • persistant cough
  • headache
  • shortness of breath 
  • unexplained weight loss
  • loss of appetite
  • heart murmurs (where your heart makes a whooshing or swishing noise between beats)

Less common symptoms

Less common symptoms of endocarditis include:

  • the appearance of a spotty red rash on the skin (this is known as petechiae)
  • narrow, reddish-brown lines of blood that run underneath the nails
  • painful raised lumps that develop on the fingers and nails
  • painful red spots that develop on the palms of your hand
  • mental confusion

When to seek medical advice

You should contact your GP as soon as possible if you develop any of the above symptoms, particularly if you have associated risk factors for endocarditis, such as a history of heart disease.

If you have these symptoms, it is unlikely that they will have been caused by endocarditis. They are more likely to be caused by a less serious type of infection. However, a diagnosis will be required to confirm this.

When to seek emergency medical advice

A stroke is one of the most serious complications that can develop from endocarditis.

If you suspect that you, or someone else, is having a stroke, you should dial 999 immediately to request an ambulance.

The most effective way to identify the symptoms of a stroke is to remember the word FAST, which stands for:

  • Face: the face may have fallen on one side, the person may be unable to smile, or their mouth, or eye, may have drooped.
  • Arms: the person may be unable to raise both arms and keep them there as a result of weakness or numbness.
  • Speech: the person’s speech may be slurred.
  • Time: it is time to dial 999 immediately if there are any of these signs or symptoms.  
^^ Back to top


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

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.

Needles and tubes

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:

  • syringes
  • catheters (a tube that is used to drain the bladder)
  • the tubes that are used during dialysis (a treatment that involves replicating the functions of the kidneys)
  • laparoscopes (a small, flexible tube that has a light source and a camera at one end and is used to help diagnose a wide range of conditions)

The effects of endocarditis on the heart

Due to its important role in your overall health, your heart is usually well protected against infection, and bacteria will usually pass harmlessly by.

However, if your heart valves are damaged, or if you have an artificial valve, it will be easier for bacteria to take root and bypass your normal immune response to infection.

The bacteria will begin to multiply and spread across the inner lining of your heart, which is known as the endocardium. The endocardium will become inflamed, causing your heart valves to become damaged. Once they are damaged, the valves may no longer be able to supply the blood that your heart needs to function properly, which can cause heart failure.

Small clumps of bacteria, known as vegetations, may develop in the heart at the site of the infection. There is a risk that these clumps will act in a similar way to blood clots, travelling away from the heart and blocking the blood supply to the organs, which can cause organ failure, or trigger a stroke if they occur in your brain.

Risk factors

There are several risk factors that can make your heart more vulnerable to infection and increase your chances of developing endocarditis. These factors are discussed below.

Heart valve disease

Heart valve disease is a general term that describes any medical condition that causes damage to the valves of the heart. Two types of heart valve disease that are known to increase your risk of endocarditis are:

  • valvular stenosis: where the valve(s) of the heart become narrowed, disrupting the blood flow through the heart
  • valvular regurgitation: where the valve(s) of the heart do not close properly, causing blood to leak back in the wrong direction

Both of these conditions can damage your heart valves, making them more vulnerable to infection. Heart valve disease can be congenital (where you are born with the condition), or acquired (where you develop the condition in later life).

Causes of acquired heart valve disease include:

  • Having a previous heart attack. A heart attack can damage the muscles that surround and support the valve, preventing the valves from functioning properly.
  • High blood pressure. Left untreated, high blood pressure (hypertension) can weaken the tissue around the valves.
  • Rheumatic fever. Rheumatic fever is a type of bacterial infection that can damage the heart.

Rheumatic fever used to be a common cause of heart valve disease. However, the condition is now much rarer as a result of the introduction of antibiotics, which are very effective in treating the condition. However, older people who have had rheumatic fever during childhood may go on to develop heart valve disease.

Prosthetic valves

Prosthetic (artificial) valves are often required to replace heart valves that have been severely damaged by heart valve disease.

Unfortunately, prosthetic valves also provide a location where bacteria can take root, which can occasionally trigger endocarditis. However, if you have a prosthetic valve, the risk of developing endocarditis is relatively low. It is estimated to be less that 1 in 100.

Intravenous drug use

People who habitually inject illegal drugs, such as heroin or methamphetamine (also known as crystal meth), into their veins have an increased risk of developing endocarditis. There are two main reasons for this:

  • Many drug users do not sterilise their needles properly, which can allow any bacteria that may be present in, or on, the needle to enter the bloodstream.
  • Repeated injections can cause skin irritation, making the skin more vulnerable to infection, and increasing the risk that infection will spread from the skin into the blood.

Fungal endocarditis

Endocarditis that is caused by a fungal infection is rarer than bacterial endocarditis, and usually more serious. Risk factors for fungal endocarditis include:

  • intravenous drug use (injecting through a vein)
  • a history of previous heart surgery
  • having a central venous catheter (a tube that is connected to a vein in the neck, groin or chest, and is used to deliver medicines and/or fluids to people who are seriously ill)
  • having a weakened immune system, either as a result of a condition that affects the immune system, such as HIV, or as a side effect of certain types of treatments, such as chemotherapy
^^ Back to top


Medical history

In order to make a diagnosis of endocarditis, your GP will look closely at your medical history, paying particular attention to any problems you may have had with your heart.

Taking a medical history will also allow your GP to identify whether you have undergone any recent medical tests or procedures that may have put you at risk of developing endocarditis. For example, if you have recently had surgery to the valves of your heart, you will be more susceptible to developing endocarditis.

Physical examination

Your GP will also examine your physical symptoms, looking for signs such as fever or nodules (small lumps) on your fingers and toes.

Your GP will also listen to your heart using a stethoscope to see if you have developed a heart murmur. A heart murmur is when you heartbeat has an extra or unusual sound. It is caused by a disturbed blood flow through the heart. If you already have a heart murmur, your doctor will listen to your heart to check that the murmur has not changed in any way.

Your GP may also refer you for a series of tests to help confirm that you have endocarditis. Because the symptoms of endocarditis are very similar to that of other conditions, it is important that your GP rules out any other possible causes.

The tests your GP may refer you for are explained below.

Blood tests

A blood culture test is usually taken to check for any bacteria or fungi that may be present in your blood stream. It can be used to isolate the specific organism responsible for the infection. If bacteria or fungi are identified then they can be tested against a variety of antibiotics to find the most effective treatment.

Another type of blood test is known as erythrocyte sedimentation rate (ESR). During an ESR test a sample of your red blood cells are placed into a test tube of liquid. They will then be timed to see how fast they fall to the bottom of the tube in millimetres per hour. If they are sinking faster than usual, this could mean that you have an inflammatory condition such as endocarditis. 90% of endocarditis patients have an elevated ESR.


An echocardiogram uses sound waves to scan your heart. These waves can then produce accurate images of the heart muscle, chambers and valves. This will allow your doctor to examine the structure and function of your heart more closely.

An echocardiogram is often used to check for any vegetations (clumps of bacteria and cells) that may have formed and can help detect infected or damaged heart tissue.

Computerised tomography (CT) scan

This type of scan uses x-rays to take pictures of your body. A computer is used to then piece the images together. A CT scan can be useful for identifying any abscesses that occur in your heart tissue.

^^ Back to top



Most cases of endocarditis will be treated with a course of antibiotics. You will normally have to be admitted to hospital so that the antibiotics can be administered intravenously (through a drip in your arm)

Whilst in hospital, blood samples will be taken regularly to measure the effectiveness of the treatment. Once fever and any severe symptoms subside you will usually be allowed to leave hospital and continue taking your antibiotics at home.

If you are taking antibiotics at home you should have regular appointments with your GP to check that the treatment is working and that you are not experiencing any side effects.The antibiotics you will usually be prescribed are penicillin and gentamicin. However, if you are allergic to penicillin, you may be prescribed vancomycin instead.

Vancomycin may also be used if tests reveal that your infection is caused by bacteria that have developed a resistance to penicillin and gentamicin, such as the meticillin-resistant staphylococcus aureus (MRSA) strain of bacteria.

Depending on the severity of your condition, you will usually have to take these antibiotics for between two to six weeks. Your doctor will normally have to take a blood sample prior to prescribing antibiotics.

This is because the antibiotics must be specific to the bacteria causing the infection. If your blood sample shows that fungi are causing your infection then you will be prescribed an anti-fungal medicine.

If your symptoms are particularly severe, you will initially be prescribed a mixture of different antibiotics before the results of the blood samples become known. This is a precautionary measure to prevent your symptoms becoming worse. Once the results of the blood samples are known, you will be given a specific antibiotic (or antifungal).


Endocarditis can cause serious damage to your heart. You may have to be referred to a cardiologist (a specialist in disease of the heart and blood vessels) so that the condition of your heart can be assessed more thoroughly.

An estimated 37-50% of people with endocarditis will require some form of surgery. This is usually to repair damage to the heart. Surgery will usually be recommended if:

  • your symptoms and/or the test results suggest that you have experienced heart failure (a serious condition where your heart is not pumping blood around your body efficiently)
  • you continue to have a high temperature (fever) despite treatment with antibiotics or antifungals
  • your endocarditis is caused by an infectious agent that is known to be particularly aggressive, such as fungi, or some types of drug-resistant bacteria
  • you experience one or more blood clots despite treatment with antibiotics or antifungals
  • you have a prosthetic (artificial) heart valve
  • the results of your echocardiogram suggest that an abscess (a collection of pus) or a fistula (an abnormal passageway) has developed inside your heart

The three main surgical procedures you may require if you have endocarditis are

  • the repair of the damaged heart valve,
  • the replacement of the damaged heart valves with artificial ones,
  • the draining of abscesses, and the repair of any fistulas, that may have developed in the heart muscle

Surgery for endocarditis can be very challenging, not least because a person who requires surgery will usually be very ill to begin with. Despite the best efforts of their surgical team, approximately 1 in 10 people will die during, or shortly after, surgery for endocarditis.

^^ Back to top


Limiting your exposure

If you have an increased risk of developing endocarditis due to factors such as heart valve disease, or having a prosthetic (artificial) heart valve, it is important that you limit your exposure to any infectious agent that could trigger a case of endocarditis.

The same is true if you have previously been affected by endocarditis because the condition can often reoccur in certain people.

The methods that you can use to limit your exposure to infection are outlined below.

Practise good oral hygiene

If you are at increased risk of developing endocarditis, it is important that you practise good oral and dental hygiene. Do not let abscesses and gum disease go untreated. You should visit your dentist on a regular basis to ensure that you maintain good oral health and to minimise the risk of bacteria entering your bloodstream through your mouth.

Take care of your skin

Regularly washing your skin with an antibacterial soap will help to lower your risk of developing a skin infection. It is also very important to wash any cuts or grazes carefully as soon as you notice them in order to prevent them becoming infected.

Contact your GP for advice if you develop the symptoms of a skin infection (see below). Your GP may prescribe antibiotics as a precaution. Symptoms of a skin infection include:

  • redness and inflammation (swelling) of the affected area of skin
  • the skin feels tender and warm to the touch
  • a discharge of pus, or fluid, from the affected area of skin

A skin infection may also make you feel generally unwell, leading to symptoms such as:

  • a high temperature (fever) of 38°C (100.4°F) or above
  • nausea
  • shivering
  • chills

You should also avoid any cosmetic procedure that involves breaking the skin, such as body piercing and tattooing.

The role of antibiotics

Before 2008, antibiotics were routinely prescribed, as a precautionary measure, to people with an increased risk of endocarditis, before they underwent routine invasive medical procedures such as:

  • dental treatment
  • childbirth
  • a bronchoscopy (where a thin, flexible tube with a small camera at the end is used to examine the inside of your throat)

However, antibiotics are no longer prescribed in these situations because research has found that the benefits of antibiotics in preventing endocarditis are outweighed by the risks that the antibiotics will cause serious side effects. For example, it is estimated that somebody with a prosthetic heart valve has a 1 in 500,000 chance of developing a fatal case of endocarditis after routine dental treatment.

In comparison, the risk of experiencing a fatal allergic reaction after taking an antibiotic, while still very low, is only 1 in 100,000. Therefore, you are five times more likely to die from taking the antibiotic than the condition that the antibiotic was meant to prevent. You also have a much higher risk of experiencing less serious, although often unpleasant, side effects, such as nausea and vomiting.

Another important reason why antibiotics are no longer used as a preventative measure is the fact that they should only be used when absolutely necessary. Each time that antibiotics are used, the chances that bacteria will become resistant to them are increased. Therefore, if you take antibiotics when there is little risk of an infection developing, they may not be as effective in fighting more serious infections in the future.

As a result of this, antibiotics will only be used if you are having a medical procedure at a site in your body where there is a suspected infection, such as in your gullet, stomach or intestines, or in your reproductive or urinary system.

^^ Back to top
“Pearn's Pharmacies, putting patients first”

Pearn's Pharmacy Services

Common Ailment Service

Primary Choice is a campaign to help the public choose the right health advice in the community.

Tell Me More


Repeat, one-off prescriptions. Collect in store or home delivery.

Sign Up

Funded Services

Browse our NHS funded services offered in our stores.

See Services


We are receiving an increase in the number of requests for delivery of medicines due to the COVID-19 pandemic.

Important Info

Find a GP   

Use our GP locator service and nearest Pearn's Pharmacy Branch

Search Now