What is the most common sign of infective endocarditis?

A persistent, unexplained fever, often with chills, night sweats and fatigue. A new or changed heart murmur is a key clinical clue, especially in someone with a known heart-valve or congenital heart condition.

Who is most at risk of infective endocarditis?

People with artificial heart valves, a previous episode of endocarditis, congenital heart disease or damaged valves, intravenous drug users, and those with pacemakers or indwelling lines.

How is infective endocarditis diagnosed?

Mainly by blood cultures and an echocardiogram — often a transoesophageal echo for a clearer view — interpreted together using established diagnostic (Duke) criteria.

With a prolonged course of intravenous antibiotics, usually around 4–6 weeks and chosen according to the organism grown. Surgery to repair or replace the valve is needed in a substantial proportion of patients.

Do I need antibiotics before every dental visit?

No. Current guidelines reserve antibiotic prophylaxis for the highest-risk patients — such as those with prosthetic valves, previous endocarditis or certain congenital heart conditions — before specific invasive dental procedures. Good daily oral hygiene matters most; ask your cardiologist or dentist what applies to you.

Infective Endocarditis (Heart Valve Infection) in Singapore

Written & reviewed by the BestDoctors.sg editorial team · Last updated 1 Sep 2026 · General information, not medical advice

Quick answer. Infective endocarditis is an infection of the inner lining of the heart – most often a heart valve – that happens when bacteria (or, less often, fungi) in the bloodstream settle and multiply on the valve. It is serious: the infection can destroy valves and shed clumps that travel to the brain, lungs or other organs. Higher-risk people include those with existing valve disease, artificial (prosthetic) valves, congenital heart disease, a previous episode, intravenous drug users, and people with indwelling lines. The classic symptom is a persistent, unexplained fever, often with chills, night sweats, fatigue and sometimes a new or changed heart murmur. See a doctor for a persistent unexplained fever, especially with a known heart-valve or congenital heart condition.

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Endocarditis is uncommon but dangerous, and it can be subtle – a lingering fever in someone with a heart condition is the pattern to watch for. Good oral hygiene is a surprisingly important part of prevention.

Red flags – act now. If you have a higher-risk heart problem (a heart-valve condition, an artificial valve, or a previous episode of endocarditis) and you develop a persistent or unexplained fever, see a doctor promptly – do not simply take paracetamol and wait for it to pass. Go to A&E or call 995 for sudden breathlessness, chest pain, or stroke symptoms – face drooping, arm weakness, or speech difficulty – as these can signal a dangerous complication.

What it is

Infective endocarditis is a serious, potentially life-threatening infection of the endocardium – the inner lining of the heart – usually affecting one or more of the heart valves. Germs circulating in the bloodstream lodge on a valve surface and grow into infected clumps known as vegetations. As these vegetations enlarge, they can eat away at the valve, stop it opening and closing properly, and break apart so that fragments travel in the blood to other organs. It is not something the body reliably clears on its own; it needs prompt hospital treatment, and the earlier it is recognised, the better the outlook.

Symptoms

Endocarditis can develop slowly over weeks or come on more quickly, which is part of what makes it tricky to spot. Fever and chills are the most common features, often with night sweats, tiredness that does not lift, aching joints and muscles, poor appetite, and weight loss. Many people also notice breathlessness, particularly on exertion or when lying flat. A doctor may hear a new or changing heart murmur. There can be small skin or nail changes – tiny dark spots, splinter-like marks under the nails, or tender lumps on the fingers or toes. If the infection has begun to cause complications, there may be stroke-like symptoms, chest or abdominal pain, or blood in the urine. The single most important pattern to remember is this: a persistent, unexplained fever in someone at higher risk should always be taken seriously, even when the person does not otherwise feel very unwell.

Who is at higher risk

Some people are far more susceptible than others. Higher risk applies to those with certain existing heart-valve problems or congenital heart conditions, anyone with a prosthetic (artificial) heart valve, and anyone who has had endocarditis before. People with some implanted heart devices, indwelling lines or long-term catheters are also more vulnerable, as are those who inject drugs. Risk is further increased by older age, diabetes and a weakened immune system. Importantly, endocarditis can follow ordinary events that briefly let germs into the blood – so a fever after such an event, in an at-risk person, deserves attention rather than a wait-and-see approach.

How germs get in

The infection begins when germs enter the bloodstream and then settle on a vulnerable part of the heart. Common entry routes include dental work or dental disease and other invasive procedures; skin infections, cuts and grazes; intravenous lines and catheters; and injecting drugs with contaminated needles. Because the mouth is such a frequent source, day-to-day oral and dental hygiene turns out to be one of the most practical defences against endocarditis.

How it is diagnosed

Diagnosis usually takes time and teamwork, because no single test settles it. The two cornerstones are blood cultures – samples of blood grown in the laboratory to identify the exact germ – and an echocardiogram, an ultrasound scan of the heart that looks at the valves for vegetations and damage. Sometimes a clearer view is needed, obtained by passing a small probe down the food-pipe (a transoesophageal echocardiogram) so the valves can be seen from close behind the heart. An ECG and other imaging may be added, and the findings are pulled together against established diagnostic criteria. Because results can take a while to come back and the picture builds up piece by piece, care is generally led by a specialist team rather than a single clinician.

Treatment

Endocarditis needs a prolonged course of antibiotics given into a vein, usually started and monitored in hospital and continued for an extended period, with the choice of antibiotic guided by the germ grown from the blood cultures. In some people the valve is too badly damaged, the infection will not clear, or the heart is under too much strain – and in those cases heart surgery to repair or replace the affected valve becomes necessary. This is demanding treatment, and it is managed by a specialist team that typically brings together cardiologists, infection specialists and, where surgery is involved, cardiac surgeons. Finishing the full antibiotic course exactly as directed matters; stopping early risks the infection returning.

Complications

The reason endocarditis is treated so urgently is the harm it can do if left to progress. The infection can wreck a valve so that it leaks or narrows, which strains the heart and can lead to heart failure. Pieces of an infected vegetation can also break off and travel in the bloodstream, blocking vessels elsewhere – lodging in the brain to cause a stroke, or reaching the lungs, kidneys or other organs. Pockets of infection can form around the heart as well. Every one of these complications is a reason that prompt recognition and treatment matter so much.

Prevention

Prevention rests on lowering the chance that germs enter the blood and reach the heart. For at-risk people this means good dental and skin hygiene, keeping up with regular dental care, and treating skin infections and wounds promptly. Some high-risk people – for example those with a prosthetic valve, a previous episode of endocarditis, or particular congenital heart conditions – may be advised to take preventive antibiotics before certain procedures; whether this applies is a decision made by their own specialist, so ask your cardiologist or dentist what is right for you. It also helps to tell healthcare providers about any heart-valve condition before dental treatment, surgery or other procedures, so they can take the appropriate precautions.

When to seek help

If you are at higher risk and have a persistent or unexplained fever, chills or night sweats, see a doctor promptly – a GP, a cardiologist, or your team at a centre such as the National Heart Centre Singapore. Do not simply take paracetamol and wait it out. Seek emergency care at A&E or call 995 for sudden breathlessness, chest pain, fainting, or stroke symptoms (face drooping, arm weakness, speech difficulty). Trustworthy general information is also available on HealthHub. When in doubt about a lingering fever in someone with a heart condition, it is always safer to be checked.

Related heart conditions & procedures

Sources

SingHealth / National Heart Centre Singapore (NHCS) — infective endocarditis (definition; how bacteria enter; risk factors; symptoms; diagnosis; treatment; prevention).
NHS — endocarditis (symptoms; risk groups; infection routes; intravenous antibiotics; surgery).
Duke-ISCVID diagnostic criteria; ESC / AHA guidelines — high-risk-only antibiotic prophylaxis before invasive dental procedures.

General information only. This guide is general information about a heart or blood-vessel condition and is not a diagnosis or personalised medical advice. See a doctor — a GP or a cardiologist — for assessment, tests and treatment. Call 995 for sudden severe chest or back pain, fainting, or stroke symptoms (face drooping, arm weakness, slurred speech).