Endocarditis

What is endocarditis?

Endocarditis is an infection of the heart's valves or its inner lining (endocardium). It is most common in people who have a damaged, diseased, or artificial heart valve.

See an illustration of endocarditis .

What causes endocarditis?

Endocarditis is caused by bacteria (or rarely, fungi) that enter the bloodstream and settle on the inside of the heart, usually on the heart valves. Bacteria can invade your bloodstream in many ways, including during some dental and surgical procedures. Having your teeth cleaned or even brushing your teeth can cause bacteria to enter the bloodstream if you don't take proper care of your teeth.¹

What increases the risk of endocarditis?

If you have a normal heart, you have a low risk of developing endocarditis. However, if you have a problem with your heart that affects normal blood flow, it increases the likelihood that bacteria or fungi will attach to heart tissue. This puts you at a high risk for endocarditis.

Some heart conditions that put you at high risk include having heart defects, heart valve problems, hypertrophic cardiomyopathy, and artificial heart valves. Other risk factors include:

• Having had endocarditis in the past.
• Having hemodialysis, which is mechanical purification of the blood.
• Injecting street drugs. This is caused by dirty needles.
• Having AIDS. Acquired immunodeficiency syndrome decreases your ability to fight infection.

What can I do if I am at risk for endocarditis?

Tell all health professionals who treat you that you are at risk for endocarditis before you have any medical, dental, or surgical procedures. You may need to take antibiotics before having dental work or oral surgery. Maintaining good oral hygiene is especially important to prevent endocarditis if you are at risk.

You may also need to take antibiotics before other surgeries, including stomach, intestinal, prostate, or gallbladder surgery. These surgeries and procedures increase your chances of getting endocarditis, especially if you already have a condition that puts you at high risk.

Your doctor can give you a card to carry in your wallet which states that you need preventive antibiotics before certain procedures.

What are the symptoms?

The symptoms of endocarditis progress as the bacteria or fungi grow in your heart. Vague, flu-like symptoms, such as a low-grade fever and fatigue, often occur first. Most people with endocarditis begin to have symptoms within 2 weeks after becoming infected with bacteria or fungi.

However, a powerful strain of bacteria may cause symptoms to appear much faster, within a few days.

Symptoms include:

• Chills and fever.
• Fatigue.
• Weight loss.
• Night sweats.
• Painful joints.
• Persistent cough and shortness of breath.
• Bleeding under the fingernails.
• Tiny purple and red spots under the skin, called petechiae.

Although symptoms are vague and may not seem worth telling your doctor about, if they persist or if you know you are at risk for endocarditis, contact your doctor.

If endocarditis is not treated, the bacteria that cause endocarditis can form growths on or around the heart valves. The growths prevent the heart valves from opening and closing properly. This interrupts the normal blood flow through the valves and interferes with the heart's pumping action. Blood can leak backwards instead of being pumped forward. Over time, heart failure can develop because your heart may not be able to pump enough blood to meet your body's needs.

Endocarditis can also cause other problems, including an abnormal heartbeat, a stroke, and kidney failure.

How is endocarditis diagnosed?

First, your doctor will ask about your medical history and do a physical exam. If your doctor thinks that you may have endocarditis, he or she will check for signs of the infection, such as a heart murmur, an enlarged spleen, skin rashes, and bleeding under your nails.

Blood cultures will be done to check for bacteria in your bloodstream, and other tests, such as an echocardiogram, may be done to check your heart function.

It is important to treat endocarditis as soon as possible to avoid permanent damage to the heart muscle or heart valves.

How is it treated?

Antibiotics given through a vein (intravenously, or by IV) are the usual treatment for endocarditis. If your heart valves are damaged by the infection or if you have an artificial heart valve, surgery to repair or replace the valve may be needed. You may also need surgery if your endocarditis is caused by a fungus. If it is not treated, endocarditis can be fatal.

Frequently Asked Questions

Most people with endocarditis have symptoms that begin within 2 weeks after becoming infected. Vague, flu-like symptoms, such as a low-grade fever and fatigue, often occur first. But infection with a powerful strain of bacteria may cause symptoms to be more severe (such as a high fever) and to appear much faster, within a few days. If symptoms persist, especially if you are at a high risk for endocarditis, see your doctor.

Symptoms include:

• Chills and fever.
• Fatigue.
• Weight loss.
• Night sweats.
• Painful joints.
• Persistent cough and shortness of breath.
• Bleeding under the fingernails.
• Tiny purple and red spots under the skin, called petechiae.

You are at increased risk if you have certain heart conditions, including heart defects, heart valve problems, hypertrophic cardiomyopathy, and artificial heart valves. Other risk factors include:

• Having had endocarditis in the past.
• Having hemodialysis, which is mechanical purification of the blood.
• Injecting street drugs. This is caused by dirty needles.
• Having AIDS. Acquired immunodeficiency syndrome decreases your ability to fight infection.

Your primary doctor can tell you whether you are at increased risk for endocarditis. Tell all other health professionals who treat you that you are at risk for endocarditis before you have any medical, dental, or surgical procedures. Your doctor can give you a card to carry in your wallet which states that you need preventive antibiotics before having certain procedures.

Symptoms of heart failure may develop if a heart valve is severely damaged.

The first step in diagnosing endocarditis is a review of your medical history and a physical exam.

Several other tests may be needed to diagnose endocarditis. They include:

• Blood cultures. Three blood cultures are recommended to identify bacteria or fungi in the bloodstream.² However, sometimes blood cultures fail to detect endocarditis and further testing is needed.
• Echocardiogram, including transthoracic echocardiogram (TTE) and transesophageal echocardiogram. These tests use high-pitched sound waves to produce an image of the heart. They can find infected areas, heart valve defects, and other abnormalities.
• Electrocardiogram (EKG, ECG). An EKG can determine whether your heart rhythm is regular. Endocarditis can cause abnormal heartbeats.

You may need other tests to identify complications of endocarditis. These tests may include:

• A chest X-ray, which can show whether your heart is enlarged or you have signs of heart failure.
• Urinalysis, which checks for blood and protein in the urine.
• Computed tomography or an MRI. These tests can tell if a blood clot caused by endocarditis has caused a stroke and may be useful when deciding upon treatment.
• Cardiac catheterization. This test may be useful if you need to have valve replacement surgery because of endocarditis. It may also be used before valve surgery to determine your risk for coronary artery disease.

There are three main goals when treating endocarditis: quickly destroy the infection; repair or replace a heart valve, if needed; and treat complications.

Destroy the infection

If you have endocarditis, you will need several weeks of treatment with one or more antibiotics. Initially, you will be treated in the hospital because the antibiotics are given through a vein (by IV), and you may need additional tests during treatment. Once your fever is gone and you are stable, you may be able to continue IV antibiotics at home with the help of a home health nurse.

Antibiotics are usually given for 4 to 8 weeks, but some people may require only 2 to 4 weeks of treatment. The antibiotics must be given long enough and at a strong enough dose to destroy all of the bacteria.

After the initial IV antibiotics, your doctor may want you to take antibiotic pills. If so, it is very important that you take them exactly as prescribed until they are gone. If your symptoms return, call your doctor right away. You probably will need more antibiotics if testing shows that the bacteria were not completely destroyed.

If endocarditis is caused by a fungus, you may need intravenous antifungal medicine. However, heart valve surgery usually is required for endocarditis caused by a fungus.

Surgery

If your heart valve becomes severely damaged from endocarditis or if infection develops in an artificial heart valve, you may need surgery to repair or replace the valve.

Complications

If you develop complications from endocarditis, such as heart failure or stroke, you may need additional treatment for these conditions.

Treatment for endocarditis is usually guided by an infectious disease specialist. A cardiologist may also be involved if your heart muscle or valves are damaged. You will need a cardiovascular surgeon if you have heart valve replacement surgery.

Once your condition has stabilized, you can probably go home where you may continue to receive antibiotic treatment through a vein (by IV). A home health nurse will help with these medicines. The nurse will teach you how to give yourself the antibiotics and how to care for your IV tube (catheter).

Be sure to tell your doctor if symptoms, such as a fever or chills, return or if you have any new symptoms.

Preventing endocarditis

If you are at risk for developing endocarditis, you will need to take antibiotics preventively before having certain medical, dental, or surgical procedures that could introduce infection-causing organisms into your blood.

If you have a normal heart and valve structure, you have a low risk of developing endocarditis. However, if you have a problem with your heart that affects normal blood flow, it increases the likelihood that bacteria or fungi will attach to heart tissue. This puts you at a high risk for endocarditis.

Some heart conditions that increase your risk include having heart defects, heart valve problems, hypertrophic cardiomyopathy, and artificial heart valves. Also, if you have had endocarditis in the past or have conditions such as AIDS that weaken your ability to fight disease, you are at greater risk.

Tell all health professionals who treat you that you are at risk for endocarditis before you have any medical, dental, or surgical procedures. You may need to take antibiotics before having any dental work or other surgeries, including oral, stomach, intestinal, prostate, or gallbladder surgery. These surgeries and procedures increase your chances of getting endocarditis. Your doctor can give you a card to carry in your wallet which states that you need preventive antibiotics before certain procedures.

If you are at increased risk of endocarditis, it is also important that you practice good oral hygiene. Floss your teeth daily, and visit a dentist twice each year. For more information, see the topic Gum Disease.

Organizations

• Congenital Heart Defects
• Coronary Artery Disease
• Heart Failure
• Mitral Valve Prolapse
• Stroke

Citations

1. Dajani AS, et al. (1997). Prevention of bacterial endocarditis: Recommendations by the American Heart Association. JAMA, 277(22): 1794–1801.

2. Sexton DJ, Bashore TM (2002). Infective endocarditis. In EJ Topol, ed., Textbook of Cardiovascular Medicine, 2nd ed., pp. 569–593. Philadelphia: Lippencott Williams and Wilkins.

Other Works Consulted

• Anderson JF, et al. (2004). Infective endocarditis. In V Fuster et al., eds., Hurst's The Heart, 11th ed., vol. 2, pp. 2001–2034. New York: McGraw-Hill.

• Durack DT, Karchmer AW (2004). Infective endocarditis. In DC Dale, DD Federman, eds., ACP Medicine, section 7, chap. 18. New York: WebMD.

• Ferrieri P, et al. (2002). Unique features of infective endocarditis in childhood. Circulation, 105(17): 2115–2127.

• Karchmer AW (2004). Infective endocarditis. In DP Zipes et al., eds., Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed., pp. 1633–1658. Philadelphia: Elsevier Saunders.

• Taubert KA, Dajani AS (1998). Preventing bacterial endocarditis: American Heart Association guidelines. American Family Physician, 57(3): 457–468.

Author:	Nancy Reid Ellie Rodgers	Last Updated May 24, 2005
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine George Philippides, MD - Cardiology
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