Infective endocarditis is a serious infection of the endocardium (the smooth interior lining of the heart ) and/or the heart valves. Although several different types of organisms can cause endocarditis, it is usually caused by a bacterial infection. Endocarditis occurs when bacteria in the bloodstream "take up residence" and begin to grow and multiply on the heart valve. Contrary to what the name might suggest, "infective" endocarditis is not in fact contagious.
There are four one-way heart valves that allow blood to be pumped forward from one chamber to another and throughout the body. At the same time these valves prevent blood from backing up into other chambers and the lungs.
Infective endocarditis may be acute or sub-acute. It can come on suddenly and become life-threatening within a matter of days, in which case it is called acute infective endocarditis. Subacute endocarditis usually develops gradually and subtly over a period of weeks to several months.
The vast majority of cases of endocarditis are caused by a bacterial infection. Heart valves that have previously been damaged in some way or are dysfunctional are believed to be more prone to develop infections, though infection can also occur on a perfectly normal heart valve.
There are numerous ways that bacteria can get into the bloodstream to cause infection of the heart valve. Something as minor as a small cut can enable bacteria that normally live on the skin to get into the bloodstream. In some cases, this can occur during a dental procedure. In hospitalized patients, the IVs and catheters that are often inserted into the veins may be the portal through which bacteria get into the blood. For many endocarditis patients, however, no clear explanation is ever found regarding how the bacteria first got into the bloodstream.
The most common cause – a bacterial infection – may present in two ways:
Risk of endocarditis increases with:
Endocarditis can cause a wide variety of symptoms, particularly in the earlier stages of infection. Patients may experience such general symptoms as fevers, chills, fatigue, weight loss, muscle aches, and sweating. These general, nonspecific, symptoms can make it hard both for the patient and the doctor to recognize endocarditis.
As infection progresses, other symptoms may develop. If the infection begins to damage the heart valve, the valve may become "leaky." A leaky heart valve can eventually lead to blood backing up into the lungs. This accumulation of fluid in the lungs can cause shortness of breath. If the infection spreads to the kidneys, patients may notice blood in the urine. If the infection spreads to the brain, it can cause headaches, confusion, or even stroke.
Acute bacterial endocarditis (ABE) has similar symptoms, but the course is much more rapid.
A physician may suspect endocarditis based on symptoms alone, especially in a patient with a predisposing condition. Patients suspected of having acute bacterial endocarditis are usually hospitalized promptly for diagnosis and treatment. Diagnostic tests may include laboratory blood counts and blood cultures, electrocardiogram, X-rays of the heart and lungs, including echocardiogram.
In some 5 to 10% of cases, fungal infection or some rare bacteria may be the cause of endocarditis and in this group the blood cultures are negative.
The goal of treatment is to eradicate the infecting organism with medications and supportive care for relieving symptoms, with hospital care during the acute phase. Once stable, some patients can continue with treatment at home. Surgery may be used to replace infected valve in patients in whom antibiotics have not been effective or in patients with artificial heart valves, or in patients with dramatically worsening symptoms.
The disease is usually curable with early diagnosis and treatment, but recovery may take weeks. If treatment is delayed, heart function deteriorates, resulting in congestive heart failure and possible death.
Left untreated, this bacterial infection can gradually "eat away" at and damage the heart valve, causing it to malfunction. It is always fatal if untreated.
Possible complications include: Infected blood clots that may travel to the brain, kidneys, or abdominal organs causing infections, abscesses or stroke; heart-rhythm disturbances (atrial fibrillation is most common); destruction of heart valves; lung clots; arthritis; myositis (inflammation of muscles); acute renal failure.
Part of prevention is to maintain good oral hygiene.
Antibiotics are required for several weeks to fight infection. Antibiotic treatment is often intravenous.
If you have heart valve damage or a heart murmur, request antibiotics prior to medical procedures that may introduce bacteria into the blood. These include dental work, childbirth and surgery of the urinary or gastrointestinal tract.
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