Infective endocarditis is an infection of the endocardium, the inner lining of the heart’s chambers and valves. This condition occurs when germs, like bacteria or fungi, enter the bloodstream and attach to the heart’s lining. The resulting inflammation can cause significant damage if not treated promptly, leading to severe health complications. While relatively rare in healthy individuals, certain factors can increase a person’s susceptibility to this infection.
Causes and Risk Factors
Infective endocarditis is caused by germs entering the bloodstream and traveling to the heart. Bacteria are the most common cause, but fungi can also be responsible, particularly in those with weakened immune systems. These microbes can enter the blood through various means, including cuts, dental procedures, or the use of unclean needles for injecting drugs.
Certain pre-existing heart conditions create a higher risk for developing infective endocarditis. These risk factors include:
- Artificial heart valves or a history of heart valve disease
- Certain congenital heart defects
- A previous episode of endocarditis
- Age-related changes in heart valves, such as calcium deposits
- Implanted cardiac devices like pacemakers
Recognizing the Symptoms
The symptoms of infective endocarditis can develop suddenly or gradually and often resemble the flu initially. Common early signs include fever, chills, fatigue, muscle aches, and night sweats. Because these symptoms are not specific to a heart infection, diagnosis can sometimes be delayed. A person might also experience a decreased appetite and unexplained weight loss.
More specific indicators often appear as the infection progresses. A primary sign is a new or changed heart murmur, an unusual sound heard between heartbeats. Other symptoms include shortness of breath, chest pain during breathing, and swelling in the feet, legs, or abdomen. Skin changes can be particularly telling, including small, painless red spots on the palms or soles called Janeway lesions, painful bumps on the fingertips or toes known as Osler’s nodes, and tiny spots under the fingernails called splinter hemorrhages.
The Diagnostic Process
Diagnosing infective endocarditis involves a combination of a physical examination and specialized tests. During an exam, a doctor will look for signs such as fever and listen for a heart murmur. The presence of a new murmur or a change in an existing one is a strong indicator that prompts further investigation.
Blood cultures are a primary step in the diagnostic process. Three or more blood samples are taken at different times to identify the specific bacteria or fungi causing the infection. This information guides the selection of the most effective antibiotic treatment. Following blood tests, an echocardiogram is used to create images of the heart to look for vegetations—clumps of germs and cell fragments—or other signs of damage.
Two types of echocardiograms are commonly used. A transthoracic echocardiogram (TTE) is a non-invasive procedure where a device is moved across the chest to produce images. For a more detailed view, a transesophageal echocardiogram (TEE) may be performed, which involves passing a small probe down the esophagus to provide a clearer picture of the heart valves.
Treatment Approaches
The primary treatment for infective endocarditis is a prolonged course of antibiotics administered intravenously. Patients are hospitalized to receive high doses of medication for several weeks, often four to six. The specific antibiotic used is determined by blood culture results, which identify the germ responsible for the infection.
In some cases, medication alone is not sufficient, and surgery becomes necessary. Surgical intervention may be required for several reasons:
- The heart valves have been severely damaged by the infection, leading to heart failure.
- The infection does not respond to antibiotic therapy.
- Large vegetations pose a high risk of breaking off and causing a stroke.
- An abscess develops within the heart muscle.
The goal of surgery is to repair or replace the damaged valves and remove any infected tissue.
Prevention Strategies
While not all cases can be prevented, individuals at high risk can take specific measures to lower their chances of developing the condition. Maintaining excellent oral hygiene is a primary strategy. Regular brushing, flossing, and dental check-ups can reduce the amount of bacteria in the mouth that could potentially enter the bloodstream.
For people with the highest risk factors, such as those with artificial heart valves or a prior history of endocarditis, preventive antibiotics may be recommended before certain procedures. These prophylactic antibiotics are prescribed before dental work that involves manipulation of the gums or incisions, as well as some respiratory or surgical procedures. At-risk individuals should discuss their specific situation with their cardiologist to determine the appropriate preventive care plan.