Definition

The endocardium is a thin layer of membrane (tissue) that covers the inner surface of the heart. Bacterial endocarditis is an infection of this membrane. Infection occurs when bacteria attach to the membrane and grow.

The infection is most common when the heart or valves have already been damaged. It can permanently damage the heart valves. This can lead to serious health problems, such as heart failure. Bacterial endocarditis can be life-threatening.

The infection can also cause growths on the valves or other areas of the heart. Pieces of these growths can break off and travel to other parts of the body. This can cause serious complications.

Causes

Bacterial endocarditis is caused by specific bacteria. Bacteria can travel to the heart through the blood. It can enter the blood from an infection somewhere else in the body. It can also enter during an activity that causes breaks in the skin or tissues. This activity can be dental work, surgery, or IV drug use.

The bacteria may be able to attach to the endocardium. Some heart conditions can increase the chance of infections. These conditions may cause blood flow to be blocked or to pool. This provides a place for the bacteria to build up.

Risk Factors

The following conditions put you at greater risk during certain procedures:

• Heart valve scarring, due to rheumatic fever or other conditions
• Artificial heart valve
• Heart defect present at birth
• Cardiomyopathy
• Prior episode of endocarditis
• Mitral valve prolapse, with significant regurgitation (abnormal backflow of blood)

The conditions listed above increase your risk of the infection with certain activities such as:

• IV drug use—risk is very high when needles are shared
• Any dental procedure, even cleanings
• Removal of tonsils or adenoids, and other procedures involving the ears, nose, and throat
• Viewing the airways though a thin, lighted tube— bronchoscopy
• Surgery on the gastrointestinal or urinary tracks, including the gallbladder and prostate

Symptoms

Symptoms vary from mild to severe, depending on:

• The bacteria causing the infection
• The amount of bacteria in the blood
• The degree of structural heart defects
• Your body’s ability to fight infection
• Your overall health

Symptoms can begin within 2 weeks of the bacteria entering the bloodstream. These may include:

• Fever
• Chills
• Fatigue
• Weakness
• Discomfort
• Unexplained weight loss
• Poor appetite
• Muscle aches
• Joint pain
• Coughing
• Shortness of breath
• Little red dots on the skin, inside the mouth, and/or under the nails
• Bumps on the fingers and toes

Note: The first symptom may be caused by a piece of the infected heart growth breaking off. This can include a stroke or other complication to another organ.

Diagnosis

The doctor will ask about your symptoms and medical history. A physical exam will be done. The doctor will listen to your heart for a murmur.

Tests may include:

• Blood tests
• Blood cultures
• Electrocardiogram (EKG)
• Imaging tests:
  • CT scan
  • Echocardiogram
  • Transesophageal echocardiogram

Treatment

Treatment will focus on getting rid of the infection in the blood and heart.

Prevention

The best way to prevent endocarditis is to avoid the use of illegal IV drugs. Certain heart conditions may increase your risk. Talk to your doctor to find out whether you are at increased risk for this condition. The American Heart Association (AHA) recommends that people at very high risk take antibiotics before and after certain dental and medical procedures.

You should also:

• Tell your dentist and doctors if you have any heart conditions.
• Maintain good oral hygiene:
  • Brush your teeth 2 times per day
  • Floss once per day
  • Visit your dentist for a cleaning at least every 6 months or as advised
• See your dentist if dentures cause discomfort.
• Get medical help right away if you have symptoms of an infection.

Mouth Healthy—American Dental Association http://www.mouthhealthy.org

Heart and Stroke Foundation of Canada http://www.heartandstroke.com

Bonow RO, Carabello BA, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2006;48:e1.

Hoen B. Epidemiology and antibiotic treatment of infective endocarditis: an update. Heart. 2006;92:1694-1700.

Infective endocarditis. EBSCO DynaMed website. Available at:
http://www.ebscohost.com/dynamed
Updated September 5, 2012. Accessed November 12, 2012.

Infective endocarditis. American Heart Association website. Available at:
http://www.heart.org/HEARTORG/Conditions/CongenitalHeartDefects/TheImpactofCongenitalHeartDefects/Infective-Endocarditis_UCM_307108_Article.jsp
Accessed November 12, 2012.