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Bacterial Endocarditis: Symptoms, Causes, Tests and Treatment

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Infective endocarditis (IE) [also called bacterial endocarditis (BE), or depending on acuity acute or subacute or chronic bacterial endocarditis (SBE) ] occurs when germs (usually bacteria) enter the blood stream and attach to and attack the lining of the heart valves. Infective endocarditis causes growths (vegetations) on the valves, produces toxins and enzymes which kill and break down the tissue to cause holes on the valve, and spreads outside the heart and the blood vessels. The resulting complications are embolism of material from the vegetations, leaky valve, heart block and abscesses around the valve. Without treatment, endocarditis is a fatal disease.

Bacterial Endocarditis

Normally, bacteria can be found in the mouth, on the skin, in the intestines, respiratory system, and in the urinary tract. Some of these bacteria may be able to get into the bloodstream when eating, during teeth brushing and when passing stools and cause endocarditis. Normal heart valves are very resistant to infection, but diseased valves have defects on the surface where bacteria may attach. Valve prosthesis (replacement heart valves) are more prone to infection than normal valves. The bacteria rapidly form colonies, grow vegetations and produce enzymes, destroying the surrounding tissue and opening the path for invasion.

Dental procedures (particularly tooth extractions) and endoscopic examinations are associated with bacteria in the blood, so prophylactic (preventative) antibiotics are advised for some patients with valve disease and all patients with valve replacements. Intravenous drug abusers are at high risk for developing IE.

Who is at risk for developing bacterial endocarditis?

Patients most at risk of developing bacterial endocarditis include those who have:

  • Acquired valve disease (for example, rheumatic heart disease) including mitral valve prolapse with valve regurgitation (leaking) and/or thickened valve leaflets
  • An artificial (prosthetic) heart valve, including bioprosthetic and homograft valves
  • Previous bacterial endocarditis
  • Certain congenital heart defects
  • Patients with devices, e.g. pacemakers
  • Immune suppressed patients
  • Patients who are intravenous drug abusers
  • Hypertrophic cardiomyopathy (HCM)

According to the American Heart Association, about 29,000 patients are diagnosed with endocarditis each year.

What are signs of infection?

Call your doctor if you have any of these signs of an infection:

  • Fever over 100°F(38.4°C)
  • Sweats or chills, particularly night sweats
  • Skin rash
  • Pain, tenderness, redness or swelling
  • Wound or cut that won't heal
  • Red, warm or draining sore
  • Sore throat, scratchy throat or pain when swallowing
  • Sinus drainage, nasal congestion, headaches or tenderness along upper cheekbones
  • Persistent dry or moist cough that lasts more than two days
  • White patches in your mouth or on your tongue
  • Nausea, vomiting or diarrhea

How is bacterial endocarditis diagnosed?

The diagnosis of bacterial endocarditis is based on the presence of symptoms, the results of a physical examination and the results of diagnostic tests:

  • Symptoms of infection (see list above), particularly a fever over 100°F (38.4°C)
  • Blood cultures show bacteria or microorganisms commonly found with endocarditis. Blood cultures are blood tests taken over time that allow the laboratory to isolate the specific bacteria that is causing your infection. Blood cultures must be taken before antibiotics are started to secure the diagnosis.
  • Echocardiogram (ultrasound of the heart) may show growths (vegetations on the valve), abscesses (holes), new regurgitation (leaking) or stenosis (narrowing), or an artificial heart valve that has begun to pull away from the heart tissue. Sometimes doctors insert an ultrasound probe into the esophagus or “food pipe” (transesophageal echo) to obtain a closer more detailed look at the heart.
  • Other signs and symptoms of bacterial endocarditis include:
    • Emboli (small blood clots), hemorrhages (internal bleeding), or stroke
    • Shortness of breath
    • Night sweats
    • Poor appetite or weight loss
    • Muscle and joint ache

How is bacterial endocarditis treated?

Once endocarditis occurs, quick treatment is necessary to prevent damage to the heart valves and more serious complications, such as death. As soon as the blood cultures have been secured the patient is started on intravenous (IV) antibiotic therapy (broad spectrum), covering as many as possible of suspected bacterial species. The antibiotics are adjusted to the sensitivity of the organism that grows from the blood culture as soon as that is available. IV antibiotics is usually given for as long as 6 weeks to cure of the infection. Symptoms are monitored throughout therapy and blood cultures are repeated to determine the effectiveness of treatment.

If heart valve and heart damage has occurred, surgery may be required to fix the heart valve and improve heart function.

After treatment is completed, the patient should be worked up for sources of bacteremia and these (for example, dental infections) should be treated. In the future, the patient should take antibiotics prophylactically according to guidelines (see Prevention).

How can bacterial endocarditis be prevented?

Traditionally, patients who were considered at risk of developing endocarditis (such as those listed above in the section, “Who is at risk of developing bacterial endocarditis?”) were advised to take antibiotics as a preventive measure before any dental, gastrointestinal or urinary tract procedure. The American Heart Association conducted a review of the scientific literature to determine the value and effectiveness of antibiotic prophylaxis (preventive antibiotics) before such procedures in reducing the risk of bacterial endocarditis.

They found the following information to be proven true, and therefore revised the guidelines for bacterial endocarditis prevention.

Summary of Infective Endocarditis (IE) Prevention Guidelines from the American Heart Association*

Endocarditis is more likely a result of daily exposure to bacteria, rather than exposure during a dental, gastrointestinal tract or genitourinary tract procedure. There may be greater risks from preventive antibiotic therapy than potential benefits if any.

  • You can reduce the risk of bacterial endocarditis by practicing good oral hygiene habits every day. Good oral health is generally more effective in reducing your risk of bacterial endocarditis than is taking preventive antibiotics before certain procedures. Take good care of your teeth and gums by:
    • Seeking professional dental care every six months
    • Regularly brushing and flossing your teeth
    • Making sure dentures fit properly
  • Learn more about good oral hygiene and heart disease
  • Not all endocarditis can be prevented. Call your doctor if you have symptoms of an infection (See signs of infection listed above). Do not wait a few days until you have a major infection to seek treatment. Colds and the flu do not cause endocarditis. But infections that may have the same symptoms (sore throat, general body aches, and fever) do. To be safe, call your doctor.
  • Only the people who have the highest risk for bacterial endocarditis will reasonably benefit from taking preventive antibiotics before certain procedures. The highest risk group for bacterial endocarditis includes those with:
    • An artificial (prosthetic) heart valve, including bioprosthetic and homograft valves
    • Previous bacterial endocarditis
    • Certain congenital heart disease including:
    • Complex cyanotic congenital heart disease such as single ventricle states, transposition of the great arteries, Tetralogy of Fallot
    • Unrepaired cyanotic congenital heart disease, including patients with palliative shunts and conduits
    • Congenital heart disease that is completely repaired by surgery or with a transcatheter device. Endocarditis prevention is reasonable for at least 6 months following the device implant. According to the American Heart Association, after 6 months, there is insufficient data to make recommendations for preventive antibiotic therapy.
    • Repaired congenital heart disease with defects still remaining at the site or next to the site of a prosthetic patch or prosthetic device
    • Heart valve disease that develops after heart transplantation
  • Importantly, the AHA no longer recommends antibiotic prophylaxis for gastrointestinal and genitourinary procedures, such as gastroscopy, colonoscopy, and cystoscopy.

If you are in the high risk group above, please follow these additional guidelines:

  • Tell your doctors and dentists you have heart disease that places you at greater risk of developing endocarditis.
  • Take antibiotics before the following procedures (as recommended by the American Heart Association):
    • All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth, or perforation of the oral mucosa.
    • Procedures of the respiratory tract or infected skin, tissues just under the skin, or musculoskeletal tissue
  • Link to Prevention of Bacterial Endocarditis Wallet Card
  • Check with your doctor about the type and amount of antibiotics you should take. Plan ahead to find out what steps you must take before the day of your procedure.
  • Carry a wallet identification card. A wallet card may be obtained from the American Heart Association with specific antibiotic guidelines. Visit their website or call your local American Heart Association office or nationally, 1.800.AHA.USA1.*
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