What is endocarditis?

Endocarditis (pronounced en-doh-car-DIE-tis) is an infection of the lining inside the heart. This lining is called the endocardium.

Bacterial infection is the most common source of endocarditis. Infection happens when bacteria enter the bloodstream, attach to the inside of the heart and multiply. This can damage or even destroy the heart valves.

A normal heart has a smooth lining that is difficult for bacteria to stick to. Congenital heart disease sometimes causes rough areas on the heart lining or other changes that make it easier for bacteria to stick to the heart lining or valves. If bacteria stick, they can survive and multiply, which can cause endocarditis.

Bacterial endocarditis is always a serious infection.

  • Endocarditis is uncommon, but it’s more likely to happen in children with heart problems. This includes children who were born with heart defects or who have damaged heart valves, artificial heart valves or devices implanted in their heart or blood vessels.

    It is extremely rare, but possible, for children with normal hearts to get endocarditis.

Endocarditis at Seattle Children’s

  • Seattle Children’s Heart Center is one of the best pediatric cardiology programs in the United States and is the top-ranked program in the Northwest, according to U.S. News & World Report. With more than 40 pediatric cardiologists, we have experience diagnosing and treating every kind of heart problem.

    Our heart team has treated many children with endocarditis. We have extensive experience with the treatment your child may require, including medicines and heart valve repair. We also have infectious disease specialists who help to choose the most appropriate therapy for the infection.

    We also have a pediatric cardiac anesthesia team and a specialized Cardiac Intensive Care Unit in case your child needs heart surgery or intensive care during their illness.

    Seattle Children’s has been treating children since 1907. Our team members are trained in their fields and in meeting the unique needs of children. For example, the doctors who give your child anesthesia are board certified in pediatric anesthesiology. This means they have extra years of training in how to take care of kids. Our child life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age.

  • When you come to Seattle Children’s, a team of people will take care of your child. Along with your child’s cardiologist, you are connected with infectious disease specialists, nurses, child life specialists, social workers and others, if their expertise is needed. We work together to meet all of your child’s health needs and help your family through this experience.

    We’re committed to your child’s overall health and well-being. We’ll discuss treatments in ways you can understand and involve you in every decision.

    Read more about the supportive care we offer.

Symptoms of Endocarditis

The symptoms of endocarditis can vary depending on the germ that caused the infection and how severe it is. Your child’s symptoms may also depend on whether they already had a heart problem before getting the infection.

Many symptoms of endocarditis resemble other illnesses, such as the flu, but usually last longer than the flu.

Endocarditis in children may cause 1 or more of these symptoms: 

  • Prolonged or recurrent fevers (for more than 5 days, or even weeks)
  • Extreme tiredness
  • Decreased appetite
  • Muscle aches
  • Achy joints
  • Small, dark spots on their hands or feet (either small painful bumps or small painless flat spots), purple-red pinpoints under their skin or dark lines under their nails 

Endocarditis can lead to other problems in the body. It can damage heart valves and cause heart failure.

Clumps of bacteria and other cells can break off from an infected area in the heart and travel through the bloodstream. This can lead to infection in another part of the body, such as the lungs, brain or kidneys. Or a clump can clog a blood vessel, blocking blood flow. These complications can cause symptoms of their own and can be serious.

Diagnosing Endocarditis

To diagnose this condition, your doctor will examine your child to see if there are signs of cardiac injury from infection or evidence that clumps of bacteria are being ejected from the heart.

The doctor will ask for details about any symptoms your child has, their health history and your family health history.

Two critical tests are almost always used together to diagnose endocarditis. One is called blood cultures, and the other is called an echocardiogram.

Blood cultures are tests used to find the bacteria causing endocarditis. Finding the exact type of bacteria causing the infection allows us to design the best treatment plan. To get this blood for culture, your child will need a needle poke into a vein. Sometimes, we will need to insert a catheter (small tube) into a vein to collect the blood. Heelstick and fingerstick blood can’t be used because bacteria living on the skin will contaminate the sample.

Echocardiography (“echo”) is the test that cardiologists use to examine the inside of the heart for signs of bacteria growing. One important echo sign is a “vegetation.” A “vegetation” is a visible clump of bacteria and cells attached to the lining of the heart or valves. Echos can also show when a cardiac valve has been injured.

Treating Endocarditis

This infection is usually treated with strong antibiotics — medicines that fight germs like bacteria.

Treatment options

Your child might need to stay in the hospital for a while and get antibiotics through a vein (intravenously, or by IV). Antibiotic treatment usually lasts 4 or 6 weeks. If your child is responding well to the IV antibiotics, your child may be able to finish IV antibiotic treatment at home. If the infection does not respond well enough to antibiotics, or if valve damage is severe, surgery may be necessary.

Preventing Endocarditis

Certain people are at risk for endocarditis. These include:

  • Children who were born with heart defects
  • People who have mechanical heart valves or cyanosis
  • People who have had heart surgery within the past 6 months
  • People who have had endocarditis before 

Talk with your doctor about whether your child needs to take any special steps for prevention.

  • The mouth is one of the most common sources of bacteria that cause endocarditis. Taking good care of the teeth and gums is the most important step everyone can take to prevent endocarditis. Children at the highest risk of endocarditis are also advised to take antibiotics before having dental work.

  • If your child is known to be at risk for endocarditis and they become ill with a sudden high fever or have a low-grade fever and tiredness for more than 5 days, they should see the doctor.

    The best way to prevent complications from endocarditis is to have the diagnosis made as early as possible so that treatment can be started before the infection causes serious damage to the heart.

Contact Us 

Contact the Heart Center at 206-987-2515 to request an appointment, a second opinion or more information.

Providers, see how to refer a patient.