Definition

The endocardium is a thin layer of membrane that covers the inner surface of the heart. Bacterial endocarditis is an infection of this membrane. It can be a life-threatening infection. The infection can also permanently damage the heart and lead to serious health problems, such as heart failure.

The infection is most common when the heart or valves have already been damaged.

Bacterial Endocarditis Copyright © 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 such as stroke or infections in the lungs or other organs.

Causes    TOP

Bacterial endocarditis is caused by specific bacteria. The bacteria may be part of an infection somewhere in the body or normally exist on the surface of skin or tissue. Bacteria can enter the blood stream through break in the skin or tissue or spread of an infection.

The blood stream will eventually pass through the heart. If the bacteria is able to stick to the heart, an infection will develop. Some heart conditions cause blood flow to be blocked or to pool, which makes it easier for bacteria to stick and grow.

Risk Factors    TOP

Certain medical conditions make it easier for bacteria to stick inside the heart. This increases the chance of bacterial endocarditis. Conditions that increase the risk of infection include:

• 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)

Activities that increase the risk of bacteria entering the blood stream include:

• IV drug use—risk is very high when needles are shared
• Dental procedure, even cleanings
• Removal of tonsils or adenoids
• Bronchoscopy

Symptoms    TOP

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    TOP

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
• ECG
• Imaging tests:
  • CT scan
  • Echocardiogram
  • Transesophageal echocardiography

Treatment    TOP

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

Prevention    TOP

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 a day
  • Floss once a 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.