What is bacterial endocarditis?

Bacterial endocarditis occurs when germs (especially bacteria) enter your blood stream and attack the lining of your heart valves.  Bacterial endocarditis causes growths or holes on your valve or scarring of your valve tissue, most often resulting in a leaky heart valve.

Normally, bacteria can be found in your mouth, on your skin, in your intestines and in your urinary tract.  If bacteria enter your bloodstream, it can cause endocarditis. 

Who is at risk?

The American Heart Association divides the risk of endocarditis into three categories:

• High-risk group includes those with:

• An artificial (prosthetic) heart valve, including bioprosthetic and homograft valves
• Previous bacterial endocarditis
• Complex cyanotic congenital heart disease
• Surgically constructed shunts or conduits

• Moderate-risk group includes those with:

• Most other congenital heart diseases – ASD, VSD, PFO, bicuspid aortic valve
• Acquired valve disease
• Hypertrophic cardiomyopathy (HCM)
• Mitral valve prolapse with valve regurgitation (leaking) and/or thickened valve leaflets

• Low or non-risk group (no greater risk than the general population) includes those with:

• Surgical repair of ASD or VSD or PFO (without permanent closure device)
• Previous coronary artery bypass surgery
• Mitral valve prolapse without regurgitation or thickened leaflets
• Physiologic, functional or innocent heart murmurs
• Previous rheumatic fever without valve dysfunction
• Cardiac pacemakers and implanted defibrillators

How can you protect yourself from bacterial endocarditis?

Ask your doctor what your risk category is and if you require bacterial endocarditis protection.
Those in the non-risk group do not have a greater risk of developing endocarditis than the general population.  It is rare for people without underlying heart disease to develop endocarditis.   Endocarditis protection is not necessary in this patient group.

If you are in the high or moderate risk group above, please follow these guidelines:

• Tell your doctors and dentists you have heart disease that places you at greater risk of endocarditis
• Call your doctor if you have symptoms of an infection (See box).  Do not wait a few days until you have a major infection to seek treatment.  Colds and flu do not cause endocarditis.  But infections that may have the same symptoms (sore throat, general body aches, and fever) do.  To be safe, call your doctor.
• Take good care of your teeth and gums by:
  •  Seeking professional dental care every six months 
  • Regularly brushing and flossing your teeth
  • Making sure dentures fit properly
• Take antibiotics prior to procedures that may cause bleeding, including:
  • Professional teeth cleaning or other dental procedures that may cause bleeding 
  • Invasive tests, such as scopes to look inside your respiratory tract (bronchoscopy), intestines (sigmoidoscopy), colon (colonoscopy), or bladder
  • Some major or minor surgeries involving the respiratory tract, stomach, intestines, urinary tract, gall bladder or prostate
  • Other types of procedures if the tissue is infected

Check with your doctor about the type and amount of antibiotics you should take. Plan ahead to find out what steps you must take before the day of your procedure.

Click here to go to the American Heart Association downloadable Bacterial Endocarditis card.

How is bacterial endocarditis diagnosed?

The diagnosis of bacterial endocarditis is based on your symptoms, clinical findings and the results of diagnostic tests:

• Symptoms of infection, particularly a fever over 100°F(38°C)
• Blood cultures show bacteria or microorganisms commonly found with bacterial endocarditis.  Blood cultures are blood tests taken over time that allow the laboratory to isolate the specific bacteria that is causing your infection.
• Echocardiogram shows growths, abscesses (holes), new regurgitation (leaking) or stenosis (narrowing), or an artificial heart valve that has begun to pull away from the heart tissue.
• Other signs and symptoms include:

o Emboli (small blood clots) hemorrhages (internal bleeding), or stroke
o Shortness of breath
o Night sweats
o Poor appetite or weight loss
o Muscle and joint aches

How is bacterial endocarditis treated?

Once blood cultures, test results indicate the specific bacteria causing the endocarditis, a course of intravenous (IV) antibiotic therapy is started.  IV antibiotics may be given for as long as six weeks to control the infection.  Symptoms are monitored throughout therapy and blood tests are performed to determine the effectiveness of treatment.  If heart valve damage has occurred, surgery may be required to fix the heart valve and improve heart function.

Bacterial endocarditis treatment starts with prevention.  Once endocarditis occurs, quick treatment is necessary to prevent damage to the heart valves and more serious complications, such as death.