Bacterial Endocarditis
A dangerous bacterial infection of the heart's inner lining and valves
Quick Facts
- Type: Cardiovascular infection
- Affected area: Heart valves and inner lining (endocardium)
- Main cause: Bacteria entering the bloodstream
- Urgency: Serious; needs prompt hospital treatment
Overview
Bacterial endocarditis, also called infective endocarditis, is an infection of the endocardium, the smooth inner lining of the heart, and especially the heart valves. It usually happens when bacteria enter the bloodstream and lodge on a heart valve or area of damaged heart tissue, where they multiply and form clumps called vegetations.
This is a serious condition that can damage heart valves, send infected fragments to other parts of the body, and become life-threatening if not treated. Most people need a long course of intravenous antibiotics in the hospital, and some require surgery. Prompt diagnosis and treatment greatly improve outcomes.
The danger comes from several directions. The infection can destroy a heart valve and lead to heart failure, and pieces of an infected vegetation can break off and travel in the bloodstream to the brain, lungs, or other organs, causing further problems such as stroke. Because these complications can develop quickly, recognizing the warning signs and starting treatment early are essential.
Symptoms
Symptoms may come on gradually over weeks or appear more suddenly with aggressive bacteria. They can include:
- Fever, chills, and night sweats
- Fatigue, weakness, and body aches
- A new or changed heart murmur
- Shortness of breath and swelling in the legs or abdomen
- Unintended weight loss and poor appetite
- Small skin spots, painful nodules on fingers or toes, or tiny red marks under the nails
A persistent unexplained fever, especially in someone with a heart valve problem or other risk factors, should be evaluated promptly. The combination of symptoms can be vague at first and easy to mistake for a lingering flu, which is one reason the diagnosis is sometimes delayed. Paying attention to the overall pattern, particularly fever that does not resolve, helps prompt timely testing.
Causes
Endocarditis develops when bacteria reach the heart through the bloodstream and attach to a vulnerable area. Bacteria can enter the blood through:
- Dental or surgical procedures involving infected or bleeding tissue
- Skin infections, wounds, or abscesses
- Intravenous drug use with contaminated needles
- Long-term intravenous lines or catheters
- Other infections that spread into the blood
Healthy valves are fairly resistant, so infection is far more likely when a valve is already abnormal, artificial, or previously damaged.
Risk Factors
- Artificial (prosthetic) heart valves or valve repair material
- Damaged, leaky, or abnormal heart valves
- Certain congenital heart defects
- A previous episode of endocarditis
- Intravenous drug use
- Long-term central venous catheters or implanted devices
- Poor dental health
Diagnosis
Diagnosis combines clinical findings with tests:
- Blood cultures: The key test, identifying the bacteria in the bloodstream so the right antibiotic can be chosen.
- Echocardiogram: Ultrasound of the heart that can show vegetations or valve damage; a probe passed down the throat (transesophageal echo) gives more detail.
- Blood tests: To detect infection, inflammation, and organ involvement.
- Other imaging: Sometimes used to find infected fragments that have traveled elsewhere in the body.
Treatment
Endocarditis requires prompt, intensive treatment, usually in the hospital:
- Intravenous antibiotics: A prolonged course, often several weeks, targeted to the specific bacteria found in blood cultures.
- Monitoring: Close follow-up of heart function, infection markers, and possible complications.
- Surgery: May be needed to repair or replace a badly damaged valve, remove infected tissue, or treat infection that is not controlled by antibiotics alone.
Treating the source, such as a dental infection or infected catheter, is also important to prevent the infection from returning.
Prevention
People at higher risk can lower their chances of endocarditis by:
- Maintaining good dental hygiene and seeing a dentist regularly
- Taking preventive antibiotics before certain dental or medical procedures, when a doctor recommends them based on risk
- Caring for skin wounds and avoiding infections
- Avoiding intravenous drug use, or seeking help and using sterile equipment and support services
- Telling all providers about any heart valve condition or prior endocarditis
When to See a Doctor
Contact a doctor promptly if you have an unexplained fever lasting more than a few days, especially if you have a heart valve problem, an artificial valve, or other risk factors. Seek emergency care if you develop:
- Severe shortness of breath or chest pain
- Sudden weakness, numbness, or trouble speaking (possible stroke from an infected fragment)
- Confusion, fainting, or a very high fever with chills
Frequently Asked Questions
How serious is bacterial endocarditis?
It is a serious, potentially life-threatening infection. It can damage heart valves, weaken the heart, and send infected fragments to the brain or other organs. With prompt diagnosis and weeks of antibiotics, many people recover, but it requires urgent medical care.
Who needs antibiotics before dental work?
Only people at the highest risk, such as those with artificial heart valves, certain congenital heart defects, or a prior episode of endocarditis, are usually advised to take preventive antibiotics before specific dental procedures. Your dentist and doctor decide based on your individual risk.
How is bacterial endocarditis treated?
Treatment centers on a prolonged course of intravenous antibiotics, often given over several weeks in or after a hospital stay, chosen to match the bacteria found in blood cultures. Surgery to repair or replace a damaged valve is needed in some cases.
What are the warning signs?
Common signs include a persistent unexplained fever, chills, night sweats, fatigue, a new heart murmur, and shortness of breath. Small skin or nail spots and painful nodules on the fingers or toes can also occur. Persistent fever in an at-risk person needs prompt evaluation.
Can endocarditis be prevented?
Risk can be reduced with good dental hygiene, prompt care of skin infections, avoiding intravenous drug use, and, for high-risk people, preventive antibiotics before certain procedures. Telling all your providers about any heart valve condition is important.
References
- Mayo Clinic. Endocarditis — Symptoms and causes.
- American Heart Association. Infective Endocarditis.
- Centers for Disease Control and Prevention (CDC). Endocarditis.
- MedlinePlus, U.S. National Library of Medicine. Endocarditis.