Bacterial Endocarditis

(Infective Endocarditis)

by Debra Wood, RN

Definition

This endocardium is a thin membrane 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 be life-threatening. It can permanently impair the heart valves. This can lead to serious health problems, such as congestive heart failure.

Bacterial Endocarditis

© 2009 Nucleus Medical Media, Inc.

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

Bacteria can travel to the heart through the blood. It can enter the blood from an infection elsewhere in the body. It can also enter during an activity that causes breaks in the skin or mucous membranes. This activity can be dental work, surgery, or IV drug use. Only certain bacteria cause this infection. The most common are:

• Streptococci
• Staphylococci
• Enterococci

The bacteria may then be able to attach to the endocardium. Some heart conditions can increase the chance of infections. These conditions may cause blood flow to be obstructed or 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
• Congenital heart defect
• 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 extremely high when needles are shared
• Any dental procedure, even cleanings
• Removal of tonsils or adenoids, and other procedures involving the ears, nose, and throat
• Bronchoscopy (viewing the airways though a thin, lighted tube)
• 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 bloodstream
• The extent of structural heart defects
• Your body's ability to fight infection
• Your overall health

The symptoms that can begin within two weeks of the bacteria entering the bloodstream include:

• Fever
• Chills
• Fatigue
• Weakness
• Malaise
• 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 cultures to test for the presence of bacteria
• Blood tests indicating signs of infections and complications related to endocarditis
• CT scan —a type of x-ray that uses a computer to make pictures of the inside of the chest
• Electrocardiogram (ECG, EKG)—a test that records the heart's activity by measuring electrical currents through the heart muscle
• Echocardiogram —a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
  • Transesophageal echocardiogram —ultrasound is passed through your mouth into the esophagus to visualize heart valves better

Treatment

Treatment will focus on getting rid of the infection from 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 recommends:

• People with high and moderate risk should take antibiotics before and after certain dental and nondental medical procedures.

In addition:

• Take an antibiotic just before and after any procedure that may put you at risk.
• Tell your dentist and other health professionals about your heart condition.
• Maintain good oral hygiene:
  • Brush your teeth twice daily.
  • Floss daily.
  • Visit your dentist for a cleaning at least every six months.
• See your dentist if dentures cause discomfort.
• Seek medical care immediately for symptoms of an infection.

American Dental Association
http://www.ada.org/

American Heart Association
http://www.americanheart.org/

Canadian Dental Association
http://www.cda-adc.ca/

Heart and Stroke Foundation of Canada
http://ww2.heartandstroke.ca/splash/

REFERENCES:

American Heart Association Medical/Scientific statement: Prevention of bacterial endocarditis. American Heart Association; 1997.

Bonow RO, Carabello BA, Chatterjee K, 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.

Braunwald E, Zipes DP, Libby P, et al. Heart Disease: A Textbook of Cardiovascular Medicine . 6th ed. Philadelphia, PA: WB Saunders Company; 2001.

Fauci AS, Braunwald E, Isselbacher KJ, et al. Harrison's Principles of Internal Medicine . 14th ed. New York, NY: The McGraw-Hill Companies; 2000.

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

Rakel RE and Bope ET. Conn's Current Therapy 2001 . 53rd ed. Philadelphia, PA: WB Saunders Company; 2001.

Last reviewed November 2009 by David N. Smith, MD
Last Updated: 11/9/2009