Endocarditis is a serious condition that affects the inner lining of the heart and its valves. It often develops when bacteria enter the bloodstream and reach the heart. However, some forms develop without an active infection.

The condition can damage heart valves and affect blood flow. In severe cases, it may also harm the brain, kidneys, lungs, or other organs. Therefore, early diagnosis and proper treatment are essential.

In this guide, you will learn about the symptoms, causes, risk factors, diagnosis, treatment, and prevention of endocarditis.

Key Takeaways

• Endocarditis affects the inner lining of the heart and may damage its valves.
• Most cases of infective endocarditis are caused by bacteria.
• Common symptoms include fever, chills, tiredness, night sweats, and shortness of breath.
• Certain heart conditions, artificial valves, and previous endocarditis can increase the risk.
• Doctors use blood cultures and heart scans to help confirm the diagnosis.
• Treatment may include antibiotics, antifungal medicines, or surgery.
• Good oral hygiene and prompt treatment of infections can help reduce risk.
• Preventive antibiotics are recommended only for selected high-risk patients before certain dental procedures.

What Is Endocarditis?

The heart has a thin inner layer called the endocardium. This layer covers the inside of the heart chambers and forms the surface of its valves.

Endocarditis occurs when this lining becomes inflamed. The condition often affects the heart valves, which control the direction of blood flow.

There are two main types of endocarditis.

Infective endocarditis: This type develops when bacteria or other microorganisms infect the inner lining or valves of the heart.

Non-infective endocarditis: This type involves small deposits on the heart valves without an active infection within those deposits. It may be linked to certain autoimmune diseases, cancers, or blood-clotting problems.

Endocarditis is different from myocarditis, which affects the heart muscle. It is also different from pericarditis, which affects the sac surrounding the heart.

Although endocarditis is uncommon, it can become life-threatening without proper medical care.

Types of Endocarditis

1. Infective Endocarditis

Infective endocarditis develops when microorganisms enter the bloodstream and attach to the heart’s inner lining or valves.

As the infection develops, small masses called vegetations may form on the valves. These masses can contain microorganisms, platelets, and a protein called fibrin.

Over time, the infection may damage the valve. Pieces of these masses can also break away and travel through the bloodstream, potentially affecting other organs.

Doctors classify infective endocarditis in several ways.

Acute and Subacute Endocarditis

Acute endocarditis develops quickly, sometimes over a few days. Patients may experience a high fever and become seriously ill.

Subacute endocarditis usually develops more slowly. Symptoms may appear over several weeks, making the condition harder to recognize at first.

However, both forms require prompt medical attention. The severity depends on the microorganism involved, the extent of valve damage, and the person’s overall health.

Native-Valve and Prosthetic-Valve Endocarditis

Native-valve endocarditis affects a person’s natural heart valve. In contrast, prosthetic-valve endocarditis affects an artificial valve or material used to repair a valve.

Infections involving artificial valves can be difficult to treat. As a result, these patients may need specialist care, prolonged medication, or surgery.

Right-Sided and Left-Sided Endocarditis

The location of the infection also matters.

• Left-sided endocarditis: This usually affects the mitral or aortic valve. Infected material may travel to the brain, kidneys, or spleen.
• Right-sided endocarditis: This usually affects the tricuspid valve. Infected material may travel to the lungs.
• Bilateral endocarditis: In this form, valves on both sides of the heart are affected.

The location helps doctors assess possible complications and plan treatment.

2. Non-Infective Endocarditis

Non-infective endocarditis occurs when small deposits form on the heart valves without an active infection in those deposits.

These masses generally contain platelets and fibrin. Although they are not caused by microorganisms growing on the valves, they can still interfere with normal heart function.

Two important forms are described below.

Nonbacterial thrombotic endocarditis (NBTE): This condition may develop in people with certain cancers, autoimmune disorders, or conditions that increase blood clotting.

Libman-Sacks endocarditis: This form is associated with systemic lupus erythematosus, an autoimmune disease. It can affect the mitral or aortic valve.

Treatment depends on the underlying illness and the risk of complications. Therefore, doctors must determine the cause before choosing the best approach.

What Causes Endocarditis?

Causes of Infective Endocarditis

Bacteria are the most common cause of infective endocarditis. However, certain fungi can also cause the condition.

Common bacteria include:

• Staphylococcus aureus
• Viridans-group streptococci
• Certain Enterococcus species
• Other bacteria that can enter the bloodstream

In rare cases, fungi such as Candida can infect the heart valves. This is more likely in certain patients with serious medical conditions or weakened immune systems.

Viruses are not typical direct causes of infective endocarditis. A viral illness may occur alongside other health problems, but this does not automatically mean the virus caused a heart-valve infection.

How Do Microorganisms Reach the Heart?

Microorganisms can enter the bloodstream through several routes.

Mouth and gum infections: Poor oral health, gum disease, and infected teeth may allow bacteria to enter the blood. This can sometimes happen during everyday activities, not only during dental procedures.

Skin wounds and infections: An infected wound or skin abscess can provide a route for bacteria to enter the bloodstream.

Injection drug use: Contaminated injection equipment can introduce microorganisms directly into the blood.

Medical devices: Certain intravenous catheters and infected implanted cardiac devices can increase the risk.

Other infections: Occasionally, an infection elsewhere in the body spreads through the bloodstream and reaches the heart.

However, these situations do not always lead to endocarditis. The risk depends on the microorganism, the person’s health, and any underlying heart conditions.

Causes of Non-Infective Endocarditis

Non-infective endocarditis may be linked to:

• Systemic lupus erythematosus and other autoimmune diseases.
• Certain cancers.
• Conditions that make blood clot more easily.
• Other serious illnesses that affect blood clotting.

In these cases, the body may form deposits on the heart valves without an active infection. Consequently, treatment focuses on the underlying disease and the risk of blood clots.

What Are the Symptoms of Endocarditis?

Symptoms can vary from person to person. Some patients become seriously ill within days, while others develop mild symptoms over several weeks.

Common symptoms include:

• Fever or chills.
• Unusual tiredness or weakness.
• Night sweats.
• Loss of appetite.
• Unexplained weight loss.
• Muscle aches or joint pain.
• Shortness of breath.
• Chest discomfort.
• Swelling in the legs, ankles, or abdomen.
• A new or changing heart murmur.
• A rapid or irregular heartbeat.

In some cases, the symptoms resemble the flu or another common infection. However, persistent symptoms should not be ignored, especially in people with heart conditions or a history of endocarditis.

Important: Not everyone with endocarditis has a fever. The absence of fever does not rule out the condition.

Skin, Nail, and Eye Symptoms

Endocarditis can sometimes cause visible changes in the skin, nails, or eyes. These findings are not present in every patient and may also occur in other conditions.

• Petechiae: Tiny red or purple spots caused by bleeding beneath the skin.
• Janeway lesions: Usually painless spots on the palms or soles.
• Osler nodes: Tender bumps that may appear on the fingers or toes.
• Splinter hemorrhages: Thin, reddish-brown lines beneath the nails.
• Roth spots: Changes in the retina that a healthcare professional may identify during an eye examination.

These signs can help doctors investigate a possible infection. Nevertheless, no single skin or nail finding can confirm endocarditis.

What Are the Complications of Endocarditis?

Endocarditis can damage the heart and affect other organs. The risk of complications depends on the severity of the condition and how quickly treatment begins.

Heart Valve Damage

Infection may damage a heart valve and prevent it from opening or closing properly. As a result, blood may flow backward through the valve.

Severe valve damage can cause heart failure. In such cases, surgery may be necessary to repair or replace the affected valve.

Heart Abscesses and Abnormal Heart Rhythms

Sometimes, the infection spreads into nearby heart tissue and forms an abscess. This can damage the structures that control the heartbeat.

Consequently, some patients develop abnormal heart rhythms or heart block. These complications may require urgent treatment.

Stroke and Other Blood Vessel Problems

Pieces of infected material can break away from a valve and travel through the bloodstream. These pieces may block blood vessels in different parts of the body.

Possible complications include:

• Stroke or other brain injury.
• Kidney damage.
• Spleen damage.
• Infected deposits in the lungs, particularly with right-sided endocarditis.
• Other organ infections.

Seek emergency medical care if you develop sudden weakness, difficulty speaking, confusion, or severe breathing problems.

Kidney Problems

Endocarditis can affect the kidneys through blood vessel blockages, inflammation, severe illness, or treatment-related complications.

For example, blood in the urine may indicate kidney involvement. Doctors may therefore check kidney function and urine samples during treatment.

Who Is at Risk of Endocarditis?

Endocarditis can affect people without a known heart condition. However, certain factors increase the risk.

These include:

• A previous episode of endocarditis.
• An artificial heart valve or valve-repair material.
• Certain congenital heart defects.
• Some heart valve disorders.
• Previous heart valve surgery.
• A heart transplant complicated by valve disease.
• Injection drug use.
• Certain infected implanted cardiac devices.
• Persistent bloodstream infections.
• Some conditions that weaken the immune system.
• Older age, particularly when other health problems are present.

Poor oral health and recurring skin infections may also contribute to risk.

Having one of these risk factors does not mean that you will develop endocarditis. Nevertheless, people at increased risk should discuss prevention and warning signs with their healthcare professional.

How Is Endocarditis Diagnosed?

Early diagnosis is important because endocarditis can cause serious complications. Doctors use a combination of symptoms, medical history, blood tests, and heart imaging to make a diagnosis.

1. Medical History and Physical Examination

First, the doctor asks about symptoms, recent infections, dental health, heart conditions, previous surgery, and implanted medical devices.

The examination may include listening to the heart for a murmur. The doctor may also check for swelling, skin changes, and other signs of complications.

2. Blood Cultures

Blood cultures help identify bacteria or other microorganisms in the bloodstream. These results can guide the choice of treatment.

Whenever possible, doctors collect blood cultures before starting antibiotics. However, emergency treatment should not be dangerously delayed in a seriously ill patient.

Sometimes, blood cultures do not identify the cause. This is known as culture-negative endocarditis. Previous antibiotic use and certain difficult-to-detect microorganisms may explain the result.

Therefore, a negative blood culture does not always rule out endocarditis.

3. Blood and Urine Tests

Doctors may order several tests to assess the infection and check for organ problems.

These can include:

• A complete blood count.
• Tests for inflammation.
• Kidney and liver function tests.
• Urine tests to look for blood or protein.
• Other tests based on the patient’s symptoms.

Although these tests provide useful information, they cannot confirm or exclude endocarditis on their own.

4. Echocardiography

Echocardiography is an ultrasound test that produces images of the heart and its valves.

A transthoracic echocardiogram (TTE) is often the first test. If more detailed images are needed, the doctor may recommend a transoesophageal echocardiogram (TEE), which uses a probe placed in the oesophagus.

However, a normal initial scan does not always exclude endocarditis. Repeat scans or other imaging may be needed when clinical suspicion remains high.

5. Other Tests

Depending on the situation, doctors may also recommend:

• An ECG to check the heart’s electrical activity.
• CT scans to investigate certain heart or blood vessel complications.
• Brain imaging if a stroke or other neurological problem is suspected.
• Specialised imaging for selected artificial-valve or implanted-device infections.

Finally, the medical team reviews all findings together to determine the diagnosis and the best treatment plan.

Endocarditis vs. Other Heart Conditions

Several heart conditions can cause similar symptoms. However, they affect different parts of the heart.

Endocarditis vs. Pericarditis

Endocarditis affects the inner lining of the heart and often its valves. In contrast, pericarditis affects the sac surrounding the heart.

Pericarditis may cause sharp chest pain that changes with breathing or body position. Endocarditis may cause fever, fatigue, and symptoms related to valve damage.

Endocarditis vs. Myocarditis

Myocarditis is inflammation of the heart muscle. It can cause chest pain, fatigue, abnormal heart rhythms, and reduced heart function.

Endocarditis, on the other hand, primarily affects the inner lining and valves.

Endocarditis vs. Rheumatic Heart Disease

Rheumatic heart disease can develop after acute rheumatic fever and may cause long-term valve damage. It is not the same as an active infection of the heart valve.

However, certain forms of existing valve disease can increase the risk of infective endocarditis.

How Is Endocarditis Treated?

Treatment depends on the cause, the affected valve, the severity of the condition, and the presence of complications.

Suspected infective endocarditis needs urgent medical assessment. Treatment may involve cardiologists, infectious disease specialists, cardiac surgeons, and other healthcare professionals.

Treatment for Infective Endocarditis

Antibiotics: Bacterial endocarditis usually requires antimicrobial medication. Doctors choose the drug based on culture results, the suspected organism, allergies, kidney function, and the type of valve affected.

Treatment often begins in hospital with intravenous antibiotics. The course may last several weeks, depending on the infection.

Patients should complete treatment as prescribed. Stopping antibiotics early or changing the dose without medical advice can lead to serious problems.

Antifungal medicines: Fungal endocarditis requires specialist-directed antifungal treatment. In some cases, surgery is also necessary.

Treatment of the infection source: Doctors may investigate whether an infected catheter, skin wound, or other source needs treatment or removal.

When Is Surgery Needed?

Medication alone is not enough for every patient. Heart surgery may be needed when:

• Valve damage causes severe heart failure.
• The infection remains uncontrolled despite appropriate treatment.
• An abscess develops near a heart valve.
• Certain artificial-valve infections cause serious complications.
• The risk of further embolic events is high in selected cases.

During surgery, the team may remove infected tissue, repair the damaged valve, or replace it with an artificial valve.

However, not everyone with endocarditis needs an operation. The decision depends on the individual patient’s condition.

Treatment for Non-Infective Endocarditis

Treatment focuses on the underlying cause and the risk of blood clots. For example, a patient may need care for an autoimmune disease or cancer.

Doctors may also consider anticoagulant medicines to reduce clotting risk. However, these medicines can cause bleeding and are not suitable for every patient.

Therefore, treatment must be planned by the medical team according to the patient’s needs.

How Can Endocarditis Be Prevented?

Not every case of endocarditis can be prevented. Still, several practical steps can help reduce some risks.

Maintain Good Oral Hygiene

Brush your teeth regularly, clean between your teeth, and visit your dentist for routine checkups.

Gum disease and infected teeth can allow bacteria to enter the bloodstream. As a result, treating dental problems and maintaining oral health are important parts of prevention.

Treat Infections Promptly

Seek medical advice for persistent or worsening infections. This is particularly important if you have an artificial heart valve, previous endocarditis, or another high-risk heart condition.

Follow the treatment plan prescribed for diagnosed infections.

Care for Wounds and Medical Devices

Keep wounds clean and follow the care instructions provided for intravenous lines or implanted devices.

In addition, report signs of infection, such as increasing redness, swelling, drainage, or fever, to your healthcare professional.

Ask About Preventive Antibiotics

Some people at the highest risk of serious complications may need preventive antibiotics before specific dental procedures.

These groups include certain patients with artificial heart valves, previous endocarditis, selected congenital heart conditions, and some heart transplant recipients with valve disease.

However, antibiotics are not routinely recommended for everyone with a heart murmur or valve problem. The decision depends on the patient’s medical history and the procedure involved.

Do not take leftover antibiotics or use them without medical advice. Good oral hygiene remains important whether or not preventive antibiotics are recommended.

Recovery and Long-Term Outlook

Recovery depends on the type of endocarditis, the extent of valve damage, and whether complications develop.

People with infective endocarditis may need several weeks of treatment and regular follow-up appointments. Even after the infection is controlled, fatigue and reduced physical stamina may continue for some time.

During recovery, patients should:

• Complete all prescribed medication.
• Attend follow-up appointments and recommended tests.
• Follow medical advice about exercise and daily activities.
• Monitor symptoms and report new concerns.
• Discuss any long-term valve problems with their cardiologist.

Some people recover without lasting heart problems. Others may need valve surgery or ongoing monitoring.

Endocarditis can also return. Therefore, unexplained fever or symptoms similar to a previous episode should be assessed promptly.

There is no single recovery time or survival rate that applies to every patient. The outlook depends on the person’s health, the cause of the condition, the severity of complications, and the response to treatment.

When Should You See a Doctor?

Contact a healthcare professional promptly if you have persistent or unexplained fever, chills, unusual tiredness, or other symptoms that may suggest endocarditis.

This is especially important if you have a previous history of endocarditis, an artificial heart valve, or another high-risk heart condition.

Seek emergency medical care immediately if you experience:

• Sudden weakness or numbness, especially on one side of the body.
• Sudden confusion or difficulty speaking.
• Severe shortness of breath.
• Severe or persistent chest pain.
• Fainting or collapse.

These symptoms may indicate a serious complication or another medical emergency. Do not wait for them to improve on their own.

Frequently Asked Questions

Can endocarditis occur without an existing heart condition?

Yes. Although certain heart conditions increase the risk, endocarditis can also affect people without a previously diagnosed heart problem.

Can endocarditis heal on its own?

Infective endocarditis should not be expected to heal without treatment. The infection can damage heart valves and cause life-threatening complications. Prompt medical care is essential.

Is endocarditis contagious?

Endocarditis itself is not generally spread directly from person to person. However, some microorganisms that cause infections can spread in particular circumstances.

Can you have endocarditis without a fever?

Yes. Fever is common in infective endocarditis, but some patients have a low fever or no fever at all. Other symptoms and risk factors still need medical attention.

How long can endocarditis go unnoticed?

There is no fixed timeframe. Acute endocarditis may worsen within days, while slower cases can cause vague symptoms over several weeks.

Because the condition can become serious, seek medical advice if you have concerning symptoms rather than waiting for them to worsen.

Does everyone with endocarditis need surgery?

No. Some patients respond to medication and careful monitoring. Surgery may be needed if the infection cannot be controlled, the valve is badly damaged, or serious complications develop.

Can endocarditis come back after treatment?

Yes. Recurrence is possible, especially in people with ongoing risk factors or certain heart conditions. Follow-up care and prompt assessment of unexplained fever are important.

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Conclusion

Endocarditis is a serious condition that affects the inner lining of the heart and may damage its valves. Most infective cases require prompt treatment with appropriate antimicrobial medicines. In addition, some patients need surgery to manage valve damage or other complications.

Recognising possible symptoms, maintaining good oral health, and seeking timely medical care can help reduce the risk of serious outcomes. If endocarditis is suspected, professional assessment is essential.

Medical Disclaimer: This article is for educational purposes only and does not replace professional medical advice, diagnosis, or treatment. If you suspect endocarditis, seek medical attention promptly. In an emergency, contact your local emergency services.

Editorial Note: This article should be reviewed by a qualified healthcare professional before publication. Add the reviewer’s name and credentials only after the review has taken place.