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What is endocarditis?

Endocarditis is a rare heart condition that occurs when there is inflammation of the endocardium, which is the inner lining of the heart wall and heart valves. In most cases, the inflammation is due to infection from bacteria, which is called infective endocarditis (IE) or bacterial endocarditis.

Infective endocarditis occurs when bacteria has entered the bloodstream from another part of the body, eventually attaching itself to the lining of the heart chambers or valves. If left untreated, the bacteria or fungus that caused the infection could create heart vegetation, which is when the infection colonizes and multiplies.

In turn, this heart infection produces toxins and enzymes that break down the heart tissue. Numerous endocarditis complications can arise from this breakdown, including embolisms (a blocked artery), leaky valves, abnormal heart rhythm, abscesses around the heart valve, heart failure, or sepsis. Although infective endocarditis is rare in anyone with a healthy heart, it is a potentially fatal heart condition.

What are the symptoms of endocarditis?

The symptoms of endocarditis are wide-ranging, which is one reason why symptoms could be confused with other heart conditions or illnesses.

Signs of endocarditis are consistent with what someone might experience with an infection—fever, sweating or chills, skin rash, painful swelling or redness, sinus drainage, muscle aches, and sore throat. Other symptoms could include a wound that does not heal or a sore with noticeable drainage.

A rapid heart rate and low blood cell count may also occur.

It is also possible to experience a dry cough lasting more than two days, nausea and vomiting, shortness of breath, loss of appetite, small blood clots, hemorrhaging, or a stroke. It is essential to know the warning signs of stroke, which are:

  • Difficulty speaking or slurred speech
  • A sudden headache
  • Problems with balance
  • Numbness in the body, particularly on one side
  • Confusion
  • Trouble with vision in either one or both eyes

Request an appointment with the heart specialists at Mass General Brigham to learn more about diagnosing and treating endocarditis.

What are the types of endocarditis?

There are two types of IE to be aware of—acute and subacute.

Acute IE is the sudden onset of endocarditis within days, which is often life-threatening.

Subacute IE, which may also be referred to as chronic IE, is slower to develop. It may last for several weeks or months.

What causes endocarditis?

A bacterial infection is the most common cause of infective endocarditis. Bacteria normally live outside and inside the body, but bacteria can enter the bloodstream if the immune system has not attacked it properly. In patients with endocarditis, the bacterial infection has traveled to the heart, which causes inflammation once it starts to multiply. A fungal infection could also cause endocarditis, but this is rare.

Bacteria can enter the body through eating or drinking, brushing teeth, going to the bathroom, or poor hygiene. Dental procedures where the gum is cut are another way of introducing bacteria to the bloodstream. Sexually transmitted diseases, using contaminated needles, or the use of a catheter are other causes of bacterial infection.

In healthy individuals, the bacteria would attach itself to the heart valve, and the body is strong enough to fight off any chance of infection. However, the chances of a heart infection increase in individuals where the heart valve is diseased or there is a replacement heart valve.

What are the risk factors for endocarditis?

Infective endocarditis is rarely seen in individuals with a healthy heart. Certain conditions or procedures can increase the risk of endocarditis, including:

  • Heart defects in children and young adults
  • Artificial heart valve replacement or other valve surgeries
  • Scarring from heart valve damage
  • Previous diagnosis of endocarditis
  • Anyone who injects illicit drugs with a contaminated needle
  • Poor oral hygiene

How is endocarditis diagnosed?

Endocarditis diagnosis often starts with a doctor listening to the heart and chest through a stethoscope during a physical examination. Your doctor will also discuss recent illnesses, surgeries, or heart problems. 

A diagnosis of endocarditis can include blood tests to confirm the presence of inflammation in the body and other conditions. A blood culture test may also be ordered to confirm if there is growth from bacteria or a fungus. 

Other tests may still be needed for the diagnosis of endocarditis, such as a chest X-ray or an electrocardiogram (EKG or ECG), which measures the heart rhythm and electrical activity. 

An ultrasound called an echocardiogram can examine the heart and valves. Chest X-rays are also useful for examining the lungs to see if there is a possibility of a lung collapse or buildup of fluid. A positron emission tomography, or PET scan, uses radioactive material to create images of the heart and pinpoint the location of an infection.

Endocarditis treatment

Endocarditis is a serious condition, and treatment should begin as soon as possible to prevent damage to the heart valves, which can lead to more serious endocarditis complications. 

A broad-spectrum antibiotic will likely be prescribed, which works to fight against a wide range of bacteria. If the bacteria causing the inflammation is identified, a more targeted antibiotic can be used. It may take several weeks of antibiotics before the infection is cured. 

Endocarditis can be fatal if left untreated and with too much damage to the heart valve. Surgery may be needed to repair the damage to the heart valve. Endocarditis is more likely to be fatal in people with existing heart valve damage or who have had a heart valve replacement.

Endocarditis recovery

The treatment regimen for endocarditis is aggressive and could last two to eight weeks or longer. Frequent blood tests will be needed to determine if bacteria is still present. 

Once the treatment regimen for endocarditis is complete, it is critical to make regular dental checkups, continue taking medications as prescribed, and keep cuts in the skin clean. If dental work is needed, discuss the procedure both with the doctor and dentist, who will likely need to prescribe a round of antibiotics before the procedure.

Endocarditis prognosis

In general, earlier treatment for endocarditis leads to a better long-term outlook. Most patients who receive aggressive treatment early will recover without any lasting effects. For patients that experience complications from endocarditis, full recovery may take longer. In cases where endocarditis has caused permanent damage to the heart, a cardiologist will work with the patient to help manage these conditions.

If a patient has already had infective endocarditis, they are at increased risk to develop endocarditis again. It is especially important for these patients to brush and floss their teeth regularly and follow their doctor’s recommendations to reduce the chances of a repeat infection.

Endocarditis prevention

Maintaining good oral hygiene, which includes brushing and flossing and keeping up with regular dental appointments, is one way to prevent endocarditis. This decreases the chance of bacteria building up in the mouth and making its way into the bloodstream. Some doctors or dentists will prescribe the use of antibiotics after dental procedures, and it is essential to complete the entire round of antibiotics. 

Anyone with a history of endocarditis or other heart disease should contact their doctor immediately if they experience any symptoms related to endocarditis, especially fatigue or fever. Anyone with this type of medical history should avoid adding body piercings, tattoos, drug usage, or any other event where bacteria could be introduced into the bloodstream.

Questions to discuss with your doctor

Talk to your doctor about any questions or concerns you may have about endocarditis treatment, recovery, or prevention. Some questions to consider are:

  • Will I need IV antibiotics, or can I take antibiotics in pill form?
  • Am I at higher risk for developing endocarditis?
  • Should I consider making any lifestyle changes to reduce my risk of getting endocarditis?
  • When can I resume daily activities and/or exercise after treatment?
  • If I’ve already had endocarditis, how can I reduce my risk of getting it again?


Endocarditis is typically caused by a bacterial infection, although there are cases where it is attributed to fungi.

Endocarditis can be successfully treated with antibiotics to target the cause of the bacterial infection. It is critical to seek treatment right away for endocarditis for the highest chance of recovery. Surgery may be needed to repair a damaged heart valve and any other damage caused by the infection.

Endocarditis and myocarditis are both examples of heart infection. Endocarditis is inflammation of the inner lining of the heart chambers and heart valve, most commonly due to a bacterial infection. Myocarditis is inflammation of the myocardium, which is the middle layer of the heart wall. Most cases of myocarditis are caused by viral infections, although bacterial, fungal, and parasitic infections are possible.

Our heart specialists at Mass General Brigham can diagnose and compose a complete treatment plan for endocarditis and other heart conditions best suited for your individual needs.