Infectious endocarditis is an infection of the lining of the heart chambers and heart valves that is caused by bacteria, fungi, or other infectious substances.

See also:

• Culture-negative endocarditis
• Endocarditis

Endocarditis is usually a result of a blood infection. Bacteria or other infectious substance can enter the bloodstream during certain medical procedures, including dental procedures, and travel to the heart, where it can settle on damaged heart valves. The bacteria can grow and may form infected clots that break off and travel to the brain, lungs, kidneys, or spleen.

Most people who develop infectious endocarditis have underlying heart disease or valve problems.

However, an organism commonly found in the mouth, Streptococcus viridans, is responsible for about 50% of all bacterial endocarditis cases. This is why dental procedures increase your chances for developing this condition. Such procedures are especially risk for children with congenital heart conditions. As a result, it is common practice for children with some forms of congenital heart disease and adults with certain heart-valve conditions to take antibiotics before any dental work.

Other common culprits include Staphylococcus aureus and enterococcus. Staphylococcus aureus can infect normal heart valves, and is the most common cause of infectious endocarditis in intravenous drug users.

Less common causes of infectious endocarditis include pseudomonas, serratia, and candida.

The following increase your chances for developing endocarditis:

• Artificial heart valves
• Congenital heart disease (atrial septal defect, patent ductus arteriosus, and others)
• Heart valve problems (such as mitral insufficiency)
• History of rheumatic heart disease

Intravenous drug users are also at risk for this condition, because unsterile needles can cause bacteria to enter the bloodstream.

Symptoms of endocarditis may develop slowly (subacute) or suddenly (acute). Fever is the classic symptom and may persist for days before any other symptoms appear.

Other symptoms may include:

• Abnormal urine color
• Blood in the urine
• Chills
• Excessive sweating
• Fatigue
• Joint pain
• Muscle aches and pains
• Nail abnormalities (splinter hemorrhages under the nails)
• Night sweats (may be severe)
• Paleness
• Red, painless skin spots on the palms and soles (Janeway lesions)
• Red, painful nodes (Osler's nodes) in the pads of the fingers and toes
• Shortness of breath with activity
• Swelling of feet, legs, abdomen
• Weakness
• Weight loss

The health care provider may hear abnormal sounds, called murmurs, when listening to your heart with a stethoscope.

A physical exam may also reveal:

• Enlarged spleen
• Splinter hemorrhages in the fingernails

A history of congenital heart disease raises the level of suspicion. An eye exam may show bleeding in the retina a central area of clearing. This is known as Roth's spots.

The following tests may be performed:

• Blood culture and sensitivity (to detect bacteria)
• Chest x-ray
• Complete blood count (may show mild anemia)
• CT scan of the chest
• Echocardiogram (ultrasound of the heart)
• Erythrocyte sedimentation rate (ESR)
• Transesophageal echocardiogram

You will be admitted to the hospital so you can receive antibiotics through a vein. Long-term, high-dose antibiotic treatment is needed to get rid of the bacteria. Treatment is usually given for 4-6 weeks, depending on the specific type of bacteria. Blood tests will help your doctor choose the best antibiotic.

Surgery may be needed to replace damage heart valves.

Early treatment of bacterial endocarditis generally has a good outcome. Heart valves may be damaged if diagnosis and treatment are delayed.

• Blood clots or emboli that travel to brain, kidneys, lungs, or abdomen
• Brain abscess
• Congestive heart failure
• Glomerulonephritis
• Jaundice
• Neurological changes
• Rapid or irregular heartbeats, including atrial fibrillation
• Severe valve damage
• Stroke

Call your health care provider if you note the following symptoms during or after treatment:

• Weight loss without change in diet
• Blood in urine
• Chest pain
• Weakness
• Numbness or weakness of muscles
• Fever

Preventive antibiotics are often given to people at risk for infectious endocarditis before dental procedures or surgeries involving the respiratory, urinary, or intestinal tract. The American Heart Association recommends antibiotics before a dental procedure if you have:

• Artificial heart valves
• Certain congenital heart defects, both before or possibly after repair
• History of infective endocarditis
• Valve problems after a heart transplant

Continued medical follow-up is recommended for people with a previous history of infectious endocarditis.

Persons who use intravenous drugs should seek treatment for addiction. If this is not possible, use a new needle for each injection, avoiding sharing any injection-related paraphernalia, and use alcohol pads before injecting to reduce risk.

Mandell GL, Bennett JE, Dolin R. Principles and Practice of Infectious Diseases. 6th ed. London: Churchill Livingstone; 2005; pp 975-1022.

Karchmer AW. Infective Endocarditis. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 8th ed. St. Louis, Mo: WB Saunders; 2007: chap 63.