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Endocarditis is a rare and potentially fatal infection of the inner lining of the heart (the endocardium). It's most commonly caused by bacteria entering the blood and travelling to the heart.
Although the heart is usually well protected against infection, it may be easier for bacteria to bypass the immune system in people who have:
People who inject drugs are also more likely to develop endocarditis.
Read more about the causes of endocarditis.
The initial symptoms of endocarditis are similar to the flu and include:
Without treatment, the infection damages the valves of the heart and disrupts the normal flow of blood through the heart.
This triggers a range of life-threatening complications, such as:
Read more about the symptoms of endocarditis.
Endocarditis is treated with a course of antibiotics given via a drip. You'll need to be admitted to hospital for this.
Around one in five people also need surgery to repair or replace a damaged heart valve or drain away any abscesses that develop.
Endocarditis is a serious illness, especially if complications develop. Even with the highest standard of medical care the risk of dying is around one in five. Early diagnosis and treatment is vital to improve the outlook for the condition.
Read more about the treatment of endocarditis.
Endocarditis is a rare condition in England, even in those with a higher risk. It's estimated to affect around one in every 3,000 people every year.
Endocarditis is more common in older people, with half of all cases developing in people aged over 50. However, cases of endocarditis have been recorded in children, particularly those born with congenital heart disease. Twice as many men are affected as women.
Although it may sound strange, rates of endocarditis are increasing because of advances in medical care. This is due to an increasing number of people being treated with valve replacement surgery or surgery to repair congenital heart disease.
The symptoms of endocarditis can develop rapidly over the course of a few days (acute endocarditis) or slowly, over the course of a few weeks or possibly months (subacute endocarditis).
Subacute endocarditis is more common in people with congenital heart disease.
The most common symptoms of endocarditis include:
Other symptoms can include:
You should contact your GP as soon as possible if you develop any of the above symptoms, particularly if you're at a higher risk of developing endocarditis, such as having a history of heart disease.
Read more about the causes of endocarditis.
These symptoms are more likely to be caused by a less serious type of infection. However, your doctor will want to investigate.
A stroke is one of the most serious complications that can develop from endocarditis.
If you suspect 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:
Endocarditis is caused by bacteria in 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 infection so 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 bacteria can develop at the site of the infection. There's a risk of these clumps acting in a similar way to blood clots, 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.
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 rare since the introduction 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 been damaged 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 veins have 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:
To diagnose 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 also allows your GP to identify whether you've undergone any recent medical procedures that may have put you at risk of developing endocarditis, such as surgery to the heart valves.
Your GP will check for the symptoms of endocarditis, such as fever or nodules (small lumps) on your fingers and toes.
They'll also listen to your heart using a stethoscope to see if you've developed a heart murmur. A heart murmur is where your heartbeat has an extra, or unusual, sound caused by a disturbed blood flow through the heart.
The symptoms of endocarditis are similar to those of other conditions, so it's important that other possible causes are ruled out. Sometimes, you may be referred for further tests.
Blood tests may be used to help diagnose endocarditis, or to help identify the most effective treatment. Blood tests may include:
ESR and CRP tests can be used to check for inflammation. About 90% of endocarditis patients have an elevated ESR or CRP.
Read more about different types of blood test.
An echocardiogram uses sound waves to scan your heart. The waves can produce accurate images of the heart muscle, chambers and valves. This allows your doctor to examine the structure and function of your heart more closely.
An echocardiogram is often used to check for any clumps of bacteria that may have formed, and can help detect infected or damaged heart tissue.
These scans can be performed by either:
The transoesophageal echo allows much clearer images of your heart as the gullet is just behind the heart.
A computerised tomography (CT) scan uses X-rays to take pictures of the inside of your body. A computer is then used to piece the images together.
A CT scan can be useful for identifying any abscesses (collections of pus) that may have developed in your body.
Most cases of endocarditis can be treated with a course of antibiotics. You'll usually have to be admitted to hospital so the antibiotics can be given through a drip in your arm (intravenously).
While you're in hospital, regular blood samples will be taken to see how well the treatment is working. Once your fever and any severe symptoms subside, you may be able to leave hospital and continue taking your antibiotics at home.
If you're taking antibiotics at home, you should have regular appointments with your GP to check that the treatment is working and you're not experiencing any side effects.
Depending on the severity of your condition, you'll usually have to take antibiotics for between two and six weeks.
Your doctor will usually take a blood sample before prescribing antibiotics to make sure you're given the most effective treatment. If your symptoms are particularly severe, you may be prescribed a mixture of different antibiotics before the results of the blood samples. This is a precautionary measure to prevent your symptoms becoming worse.
If your blood sample shows that fungi are causing your infection, you'll be prescribed an antifungal medicine.
Endocarditis can cause serious damage to your heart. You may be referred to a cardiologist (a specialist in diseases of the heart and blood vessels) so the condition of your heart can be assessed more thoroughly.
Between 15% and 25% of people with endocarditis need some form of surgery. This is usually to repair damage to the heart. Surgery will usually be recommended if:
The three main surgical procedures that are used to treat endocarditis are:
Surgery for endocarditis can be very challenging, not least because a person who needs surgery will usually be very ill to begin with. Despite the best efforts of their surgical teams, approximately one in 10 people will die during or shortly after surgery for endocarditis.
If you have an increased risk of developing endocarditis, it's important to limit your exposure to any infection that could trigger it.
The same is true if you've previously been affected by endocarditis, as the condition can often reoccur in certain people.
If you're at increased risk of developing endocarditis, it's important that you practise good oral and dental hygiene.
You should visit your dentist on a regular basis to ensure you maintain good oral health and to minimise the risk of bacteria entering your bloodstream through your mouth.
Read more about dental health.
Regularly washing your skin with an antibacterial soap will help to lower your risk of developing a skin infection. It's also very important to wash any cuts or grazes carefully as soon as you notice them 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:
A skin infection may also make you feel generally unwell, leading to symptoms such as:
You should also avoid any cosmetic procedure that involves breaking the skin, such as body piercing and tattooing.
Read more about skin care.
Research has found that the benefits of antibiotics in preventing endocarditis are outweighed by the risks that they'll cause serious side effects.
Antibiotics should only be used when absolutely necessary. Each time antibiotics are used, the chances that bacteria will become resistant to them are increased.
Read more about antibiotic resistance.
Antibiotics will only be prescribed as a precautionary measure if a medical procedure is taking place at a site in your body where there's a suspected infection, such as your: