What is infective endocarditis?
Infective endocarditis (IE), one of two types of endocarditis, is an infection of the endocardium, a smooth, functional layer of tissue that lines the heart’s chambers and valves.
The infection damages the valves and internal structures of the heart, often causing serious dysfunction and complications.
The condition is also known as bacterial endocarditis because the infective agents present are usually bacteria.
Why are heart valves susceptible to infection?
White blood cells (leukocytes – immune system cells that prevent infection in the body) cannot reach the valves because the mitral, tricuspid, aortic, and pulmonary valves of the heart do not receive a dedicated supply of blood. This makes them prone to infections.
Infectious organisms may attach themselves to valve surfaces and form vegetations (anomalous growths), particularly if the valves are damaged, faulty, or abnormal in some way.
What causes bacterial endocarditis?
Bacteria that enter the bloodstream are the cause of infection. The three most common types of infective bacteria are streptococcus, staphylococcus aureus/epidermidis, and enterococcus.
Less commonly, HACEK organisms are the infecting agents, and even less frequently, fungi like candida albicans, histoplasma, or aspergillus. Though rare, brucella–related infections and coxiella burnetii can also cause infection and damage the heart’s valves.
How do you get infective endocarditis?
Bacteria can enter the blood through dental procedures that cut the gums, daily oral activities like tooth brushing, flossing, and eating, and infected wounds or cuts on the skin.
Bacteria can also enter the blood through needle and catheter usage (e.g., tattoos, drug abuse, medical procedures), intestinal disorders, and sexually transmitted diseases.
Streptococci are usually due to oral activities and dental work. Staphylococci are typically associated with skin piercings. Enterococcus can occur as a result of genitourinary or gastrointestinal tract irregularities.
Who is at risk of developing endocarditis?
People with congenital or rheumatic heart disease, hypertrophic cardiomyopathy, and mitral valve prolapse (with regurgitation) generally have a higher risk of developing the infection.
Patients who have had it before are also at risk, as are those with prosthetic valves, immunodeficiency disorders, diabetes, certain cancers (especially colorectal), and urinary tract infections.
Other IE risk factors include intravenous drug abuse (repeatedly using contaminated needles to inject drugs and/or not sterilizing the skin before injections) and poor dental hygiene.
What are the symptoms of endocarditis?
There are numerous symptoms. The most common symptoms are fever, fatigue, and malaise (feeling ill). Patients often also experience coughing and unexplained weight loss. Very importantly, a new heart murmur may develop, or changes in an existing murmur may become evident.
Other symptoms include shortness of breath, spleen tenderness, chest pain, nausea, and congestion, as well as headaches, muscle aches, painful or swollen joints, skin rashes, night sweats, and chills.
What are the signs of endocarditis?
In addition to the variety of symptoms that may occur with IE, a number of physical signs may also become apparent in people who develop the infection.
Signs include lesions at the back of the eye (roth’s spots), inflamed and painful nodes on the hands and feet (osler’s nodes), painless node-like lesions on the soles and palms (janeway lesions), and splinter hemorrhages (dark vertical lines) that appear under the nails.
All of the above, apart from janeway lesions, can be signs or symptoms of an unrelated condition.
How is endocarditis diagnosed and tested?
Infective endocarditis may be suspected based on your symptoms and medical history. A physical examination is normally the first step. Then, a number of other tests may be performed.
A blood culture can detect bacteria and anemia. An echocardiogram can give the doctor a good look at the valves, revealing vegetations. An electrocardiogram (ECG) can reveal heartbeat irregularities. A chest x-ray provides visuals of the lungs and heart. A CT scan or MRI can show if the infection has spread.
How is endocarditis treated?
Once a doctor diagnoses IE, immediate hospital treatment is necessary to treat the infection and complications and prevent further damage. Once admitted, high doses of antibiotics (penicillin, gentamicin, or vancomycin) are administered intravenously, while the patient is monitored.
The hospital stay general lasts four to six weeks, and then antibiotic therapy is continued at home or when visiting the doctor. Surgery may be required, depending on circumstances.
How is endocarditis prevented?
It can be prevented by maintaining good oral hygiene and avoiding procedures that may infect the skin. If there is a skin infection, or wounds that are slow to heal, see a physician without delay.
Preventative antibiotics (prophylaxis) can also be taken before invasive dental work and medical procedures, if appropriate. Doctors only prescribe these drugs to patients at high risk of infection.
What is the prognosis for IE patients?
Infective endocarditis is a serious disease. Left untreated, the person with the infection will eventually die. With treatment, the overall mortality rate for in-hospital patients is 20-30 percent. Death usually occurs due to valve dysfunction and congestive heart failure, which are complications of IE.
Surgery (normally to repair or replace a valve), while not always necessary initially, may be required within a few years of successfully treating the infection. Even if the infection is successfully treated, a patient may continue to experience complications and symptoms.