Endocarditis occurs when germs enter your bloodstream, travel to your heart, and attach to abnormal heart valves or damaged heart tissue. Certain types of bacteria cause most cases, but fungi or other microorganisms also may be responsible.
Usually, your immune system destroys harmful bacteria that make it into your bloodstream. Even if bacteria reach your heart, they may pass through without causing an infection. However, bacteria that live in your mouth, throat or other parts of your body, such as your skin or your gut, can sometimes cause serious infections like endocarditis under the right circumstances.
Bacteria, fungi or other germs that cause endocarditis might enter your bloodstream through:
- Everyday oral activities. Activities such as brushing your teeth, or other activities that could cause your gums to bleed, can allow bacteria to enter your bloodstream â especially if you don't floss or your teeth and gums aren't healthy.
- An infection or other medical condition. Bacteria may spread from an infected area, such as a skin sore. Other medical conditions, such as gum disease, a sexually transmitted infection or certain intestinal disorders â such as inflammatory bowel disease â can also give bacteria the opportunity to enter your bloodstream.
- Catheters. Bacteria can enter your body through a catheter â a thin tube that doctors sometimes use to inject or remove fluid from the body. This is more likely to occur if the catheter is in place for a long period of time.
- Needles used for tattoos and body piercing. The bacteria that can cause endocarditis can also enter your bloodstream through the needles used for tattooing or body piercing.
- Intravenous (IV) illegal drug use. Contaminated needles and syringes are a special concern for people who use illegal intravenous (IV) drugs, such as heroin or cocaine. Often, individuals who use these types of drugs don't have access to clean, unused needles or syringes.
- Certain dental procedures. Some dental procedures that can cut your gums may allow bacteria to enter your bloodstream.
Bacteria can more easily attach to the lining of your heart (endocardium), if the lining's surface is rough. You're also more likely to develop endocarditis if you have faulty, diseased or damaged heart valves. However, endocarditis does occasionally occur in previously healthy individuals.