Endocarditis

Endocarditis is an inflammation of the heart valves caused by bacteria. Symptoms include fever, chills, fatigue, weakness, aching joints and muscles, night sweats, and others.

Endocarditis describes inflammation of the inner lining of the heart and almost always involves the heart valves. The endocardium (endo=inside +cardia=heart) includes the inner lining of the chambers of the heart, as well as the four valves that help direct blood flow as the heart beats.

Most cases of endocarditis are due to an infection elsewhere in the body that then get deposited on the valve surfaces inside the heart. These deposits or vegetations can grow, damage the valve, and prevent proper blood flow through the heart. Bits of vegetation can also break off and travel or embolize to other parts of the body.

What is infective endocarditis?

Most cases of endocarditis are caused by an infection that travels from elsewhere in the body to infect the heart valves. The infection may be due to complications of medical procedures where intravenous lines or other devices are implanted in the body and left in place for a longer period of time. If these lines become infected, bacteria can travel in the blood stream and then infect the heart valves. Often, the heart valves may have already sustained some type of damage, like from congenital heart disease, rheumatic fever, or an artificial heart valve that has been replaced.

Some cases of infective endocarditis are a complication of intravenous drug use.

There are some cases of endocarditis that are not due to infection. Nonbacterial thrombotic endocarditis usually involves normal heart valves and no infection is involved. It may be a complication of some types of cancer and systemic lupus erythematosus.

What is the most common cause of endocarditis?

Bacterial infection is the most common cause of endocarditis, most often due to streptococcus or staphylococcus infections that travel through the bloodstream to infect already damaged parts of a heart valve. Most often, it is the mitral or aortic valves on the left side of the heart that are involved. The aortic valve directs blood from the left ventricle into the aorta and then to the body. The mitral valve directs blood from the left atrium to the left ventricle, and prevents backwash of blood when the heart beats and sends blood to the aorta.

In addition to strep and staph infections, there can be fungal infections as the cause of endocarditis.

COVID-19 may be a potential infectious agent that is associated with endocarditis.

Common sources of that infection include intravenous lines, such as central venous lines and hemodialysis lines, and implanted heart devices like a defibrillator or pacemaker. Sometimes the infection will be introduced into the body because of surgery or a dental procedure.

Intravenous drug users are at higher risk of endocarditis because of infected needles and poor sterile technique when injecting drugs into a vein. In these patients, it is often the tricuspid valve that is involved. It is on the right side of the heart and connects the right atrium with the right ventricle.

Endocarditis usually occurs in patients who have previous heart valve damage or underlying heart disease. Some examples include:

• Existing abnormal heart valves including:
  • aortic stenosis
  • mitral stenosis
  • mitral regurgitation
• Heart valve replacement or heart valve repair
i>Congenital heart disease

Patients with pacemakers or implanted defibrillators also carry an increased risk of endocarditis.

Other risks include cancer and immunosuppression.

Those at risk may need to take prophylactic (preventive) antibiotics prior to surgical or dental procedures. Check with your health care provider and dentist to determine whether antibiotics are recommended to prevent infection.

Almost all patients with endocarditis present with fever and chills. Other common symptoms include:

• Malaise
• Fatigue
• Weakness
• Muscle aches
• Night sweats
• Shortness of breath
• New or changing heart murmur when associated with new or unexplained fever.

There are other classic skin lesions that may occur, but though listed as classic, do not occur routinely. These may include:

• Janeway lesions - a rash on the palms
• Roth spots - seen on the retina during an eye examination
• Osler nodes – thickening on the pads of the fingertips and toes
• Splinter hemorrhages – vertical lines seen underneath the fingernails

This diagnosis needs to be considered in any patient with a new, unexplained fever who has risk factors for endocarditis. The health care provider needs to have a high index of suspicion of the diagnosis and needs to ask about recent dental procedures, surgery, or intravenous drug use.

Duke’s Clinical Criteria may be used to make the diagnosis. They are a combination of clinical, lab, and diagnostic test results used to direct the health care provider to the diagnosis.

Physical examination will specifically include listening to the heart sounds to determine if a new heart murmur can be detected, and examining the skin, especially the palms and fingers.

Multiple blood cultures (a blood test) will routinely be done to try to grow the bacteria from the bloodstream and help direct antibiotic therapy.

Chest X-ray and EKG are routinely done.

Both a transthoracic echocardiogram (TTE) and transesophageal echocardiogram (TEE) will be done. The TTE uses an ultrasound probe on the chest wall to evaluate the heart structure and function. In a TEE, the probe is placed in the esophagus by the cardiologist, as the patient swallows the tube. The esophagus is located immediately adjacent to the heart and the probe placement allows closer inspection of the heart. Sometimes, only a TEE is performed. This test will allow the cardiologist to look for vegetations on the heart valves, to determine heart valve function and to assess overall heart pumping capability.

CT, MRI, and PET scans of the heart may be considered.

If there are symptoms present that affect other organs of the body, other tests may be considered. For example, a patient with stroke-like symptoms may require an MRI of the head. A patient with back pain may cause work for bony infections of a vertebra and may need a CT or MRI for that evaluation.

The first treatment for endocarditis is prevention. For patients who are at risk for the infection, prophylactic (preventive) antibiotics prior to surgery or major dental procedures may be considered.

Infective endocarditis is treated with intravenous antibiotics for a minimum of two weeks and potentially six weeks or longer.

There is an urgency to begin treatment, since improved outcomes are associated with early treatment. For that reason, treatment with intravenous antibiotics may be started before the definitive diagnosis has been made.

Heart valves do not have good blood supply, so intravenous antibiotics are used to increase the concentration of medication delivered to them.

The source of infection also needs to be found and potentially treated. For example, if the source of bacteria is an infected hemodialysis shunt, it may need to be replaced. Similarly, if a pacemaker site was infected, it would need to be evaluated and treated as well.

Surgery for endocarditis

Surgery is indicated for patients whose heart valve is damaged because of the endocarditis infection.

For patients with artificial valves, early surgery may be recommended, but its timing needs to be individualized for each patient.

The complications of endocarditis can be divided into those that affect the heart valve, and those that are due to embolization of bits of vegetations and bacteria to other parts of the body.

Heart valves may become damaged because of the vegetations that grow on their leaves. This can lead to valve destruction and heart failure.

Vegetations can embolize or travel in the body stream and cause infections or abscess formation. As well, the vegetations can clog small arteries and cause strokes or pulmonary embolism.

Kidney damage may occur.

Endocarditis without treatment is fatal.

Prognosis with antibiotic and surgical therapy depends upon the age of the patient, what type of bacteria caused the infection, how long the infection was present prior to treatment, how much heart valve damage occurred, and the underlying health of the patient.

Streptococcus and staphylococcus infections may have a survival rate of 90% or more, while fungus infections rate may be less than 50%.

Patients with artificial valves or congenital heart disease have survival rates up to 15% lower.

Can endocarditis be cured?

The goal for treating endocarditis is the complete eradication of the infection, but it is important to remember that there is usually an underlying heart problem that allowed the endocarditis to occur. These issues will also need to be addressed.