What Causes Endocarditis?
Infective endocarditis (IE) occurs when bacteria,
fungi, or other germs invade your bloodstream and attach to abnormal areas of
your heart. Certain factors increase the risk of germs attaching to a heart
valve or chamber and causing an infection.
A common underlying factor in IE is a structural
heart defect, especially
faulty
heart valves. Usually your immune system will kill germs in your
bloodstream. However, if your heart has a rough lining or abnormal valves, the
invading germs can attach and multiply in the heart.
Other factors, such as those that allow germs to
build up in your bloodstream, also can play a role in causing IE. Common
activities, such as brushing your teeth or having certain dental procedures,
can allow bacteria to enter your bloodstream. This is even more likely to
happen if your teeth and gums are in poor condition.
Having a catheter or other medical devices inserted
through your skin, especially for long periods, also can allow bacteria to
enter your bloodstream. People who use intravenous (IV) drugs also are at risk
for infections due to germs on needles and syringes.
Bacteria also may spread to the blood and heart from
infections in other parts of the body, such as the gut, skin, or genitals.
Endocarditis Complications
As the bacteria or other germs multiply in your
heart, they form clumps with other cells and matter found in the blood. These
clumps are called vegetations (vej-eh-TA-shuns).
As IE worsens, pieces of the vegetations can break
off and travel to almost any other organ or tissue in the body. There, the
pieces can block blood flow or cause a new infection. As a result, IE can cause
a wide range of complications.
Heart Complications
Heart problems are the most common complication of
IE. They occur in one-third to one-half of all people who have the infection.
These problems may include a new
heart
murmur,
heart
failure, heart valve damage,
heart
block, or, rarely, a
heart
attack.
Central Nervous System Complications
These complications occur in as many as 20 to 40
percent of people who have IE. Central nervous system complications most often
occur when bits of the vegetation, called emboli (EM-bo-li), break away and
lodge in the brain.
There, they can cause local infections (called brain
abscesses) or a more widespread brain infection (called meningitis).
Emboli also can cause a stroke or seizures. This
happens if they block blood vessels or affect the brain's electrical signals.
These complications can cause long-lasting damage to the brain and may even be
fatal.
Complications in Other Organs
IE also can affect other organs in the body, such as
the lungs, kidneys, and spleen.
Lungs. The lungs are especially at
risk when IE affects the right side of the heart. This is called right-sided
infective endocarditis.
A vegetation or blood clot going to the lungs can
cause a pulmonary
embolism and lung damage. Other lung complications include
pneumonia
and a buildup of fluid or pus around the lungs.
Kidneys. IE can cause kidney
abscesses and kidney damage. IE also can cause inflammation of the internal
filtering structures of the kidneys.
Signs and symptoms of kidney complications include
back or side pain, blood in the urine, or a change in the color or amount of
urine. In a small number of people, IE can cause kidney failure.
Spleen. The spleen is an organ
located in the left upper part of the abdomen near the stomach. In as many as
25 to 60 percent of people who have IE, the spleen enlarges (especially in
people who have long-term IE).
Sometimes, emboli also can damage the spleen. Signs
and symptoms of spleen problems include pain or discomfort in the upper left
abdomen and/or left shoulder, a feeling of fullness or the inability to eat
large meals, and hiccups.
|