Endocarditis (Infective Endocarditis)

How endocarditis develops

Normal heart valves resist infection. When valves are abnormal or damaged, or an artificial device is present, small clots form on their surface. If bacteria enter the blood, from the mouth, skin, a catheter or injecting drugs, they can stick to these clots and multiply, forming vegetations. These can:

• destroy valve tissue, causing leaky valves and heart failure
• break off and travel as emboli to the brain, kidneys, spleen, limbs or, from the right side of the heart, the lungs
• spread into the heart muscle, causing abscesses and heart block
• trigger immune reactions that affect the kidneys and joints

Acute endocarditis, often from Staphylococcus aureus, develops over days and is very aggressive. Subacute endocarditis, often from mouth streptococci, develops over weeks to months with vague symptoms. Our infective endocarditis page has more on specific organisms.

Symptoms

• fever and chills, the most common symptom
• fatigue, weakness and muscle or joint aches
• night sweats and weight loss
• shortness of breath and leg swelling (heart failure)
• a new or changed heart murmur
• chest pain
• tiny red or purple spots on the skin, inside the mouth or on the whites of the eyes (petechiae)
• splinter hemorrhages: thin dark lines under the nails
• Osler nodes: painful red bumps on the fingertips or toes
• Janeway lesions: painless flat red spots on palms or soles
• signs of emboli: stroke symptoms, sudden leg pain, flank pain, blood in urine

Older people may have only tiredness, confusion or weight loss.

Who is at risk

Highest risk

• artificial (prosthetic) heart valves, including transcatheter valves
• previous endocarditis
• certain congenital heart disease, especially if unrepaired or repaired with prosthetic material
• heart transplant recipients with valve disease

Other risk factors

• injection drug use
• pacemakers and defibrillators
• degenerative valve disease and mitral valve or aortic valve disease
• previous rheumatic fever damage, common worldwide
• hemodialysis and long-term IV catheters
• poor dental health
• older age, diabetes and weakened immunity

Diagnosis

Doctors use the Duke criteria, combining:

1. Blood cultures: at least three sets from separate draws before antibiotics. Typical organisms in multiple cultures are a major criterion.
2. Echocardiography: transthoracic echo first, and transesophageal echo (a probe in the food pipe) for better views, especially with prosthetic valves.
3. Other features: fever, risk factors, emboli, immune phenomena.
4. Additional imaging: PET-CT or cardiac CT, especially for prosthetic valves and devices. Brain imaging if neurological symptoms occur.

Blood tests often show anemia, raised inflammation markers and blood in the urine.

Treatment

Antibiotics

• high-dose IV antibiotics chosen by the organism, usually for 4 to 6 weeks
• some stable patients can complete treatment with outpatient IV therapy or, in selected cases, switch to oral antibiotics after an initial IV phase
• antifungal treatment for fungal endocarditis

Surgery

About half of patients need valve surgery to repair or replace the infected valve. Indications include:

• heart failure from valve damage
• uncontrolled infection, abscess or resistant organisms
• large vegetations with high embolic risk, or after emboli
• most infected pacemaker or defibrillator systems need complete removal

Addressing the source

Dental treatment, removing infected lines, and addiction treatment for people who inject drugs, which reduces reinfection.

Complications

• heart failure
• stroke and other emboli
• heart abscess and heart block
• kidney damage
• septic emboli to the lungs and lung abscesses (right-sided endocarditis)
• infected aneurysms (mycotic aneurysms)
• sepsis

Outlook

Endocarditis remains serious, with in-hospital mortality of roughly 15 to 20% and higher with Staphylococcus aureus or prosthetic valve infection. Prompt diagnosis, appropriate antibiotics and timely surgery improve survival. Survivors remain at higher risk of a second episode.

Prevention

• Good oral hygiene and regular dental care, the most important measure, since daily brushing and chewing release mouth bacteria into the blood
• Antibiotics before dental procedures are recommended only for people at highest risk (prosthetic valves, previous endocarditis, certain congenital heart disease, heart transplant with valve disease), for procedures involving the gums or root area
• avoid tattoos and piercings in unsafe settings
• careful skin care around catheters
• harm reduction and treatment for injection drug use: sterile equipment, never sharing needles

Frequently asked questions

What are the first signs of endocarditis?

Early signs are often fever, chills, tiredness, aching muscles and joints, night sweats and loss of appetite, which can feel like flu. A new heart murmur, breathlessness or small spots on the skin or nails may follow. Persistent fever in someone with a heart valve problem needs prompt evaluation.

How do you get endocarditis?

It develops when bacteria in the bloodstream settle on damaged or artificial heart valves. Bacteria enter from the mouth through gum disease or dental work, from the skin through injections or catheters, or from other infections. People with prosthetic valves or previous endocarditis are most at risk.

Is endocarditis curable?

Yes. Most people are cured with 4 to 6 weeks of IV antibiotics, and many also need heart valve surgery. It is a serious infection, and outcomes are best when it is diagnosed and treated early.

Do I need antibiotics before dental work?

Only if you are at highest risk: an artificial heart valve, previous endocarditis, certain congenital heart conditions, or a heart transplant with valve disease. Most people with other valve problems, such as mitral valve prolapse, do not need them. Ask your cardiologist.

Can endocarditis cause a stroke?

Yes. Pieces of infected vegetation can break off and travel to the brain, causing a stroke. This happens in a significant minority of patients, most often in the first weeks of infection, and is one reason surgery may be recommended for large vegetations.