Bacterial Endocarditis (Infective Endocarditis) Causes, Symptoms, Diagnosis, Treatment,Prevention

Bacterial Endocarditis (Infective Endocarditis) Causes, Symptoms, Diagnosis, Treatment,Prevention

What is Bacterial Endocarditis (Infective Endocarditis)?

Bacterial endocarditis (BE, also called infective endocarditis) is an infection of the heart valves or the heart’s inner lining (endocardium). Bacterial endocarditis occurs when germs (especially bacteria but occasionally fungi and other microbes) enter the blood stream and attack the lining of the heart or the heart valves. Bacterial endocarditis causes growths or holes on the valves or scarring of the valve tissue, most often resulting in a leaky heart valve. Without treatment, bacterial endocarditis can be a fatal disease.

Normally, bacteria can be found in the mouth, on the skin, in the intestines, respiratory system, and in the urinary tract. Endocarditis can occur if certain types of bacteria enter the bloodstream.

Bacterial endocarditis does not occur very often, but when it does, it can cause serious heart damage. It is very important to prevent this infection from occurring, if possible.

Causes of Bacterial Endocarditis (Infective Endocarditis)

Bacterial endocarditis occurs when bacteria (germs) enter the bloodstream and lodge inside the heart, where they can multiply and cause infection.

A normal heart has a smooth lining with normal valve structures, making it difficult for bacteria to stick to them. Persons with congenital heart disease may have abnormal inner heart linings due to thickened valves that cause abnormal opening or leaking of the valve. Even after surgery, roughened areas may remain due to scar tissue formation or surgical patches used to redirect blood flow. These rough areas inside the heart are inviting and opportune places for bacteria to build up and multiply.

How Bacteria Enters the Body

Bacteria can enter the body in many ways. According to the American Heart Association (AHA), some of the most common ways include:
  • Dental procedures (including professional teeth cleaning)
  • Tonsillectomy or adenoidectomy
  • Examination of the respiratory passageways with an instrument known as a rigid bronchoscope
  • Certain types of surgery on the respiratory passageways

How does the infection occur?

Bacterial endocarditis occurs when bacteria (germs) enter the bloodstream and lodge inside the heart, where they multiply and cause infection.

A normal heart has a smooth lining, making it difficult for bacteria to stick to it. However, persons with congenital heart disease may have a roughened area on the heart lining caused by pressure from an abnormal opening or a leaky valve. Even after surgery, roughened areas may remain due to scar tissue formation or patches used to redirect blood flow. These rough areas inside the heart are inviting, opportune places for bacteria to build up and multiply.

Who is at risk for Bacterial Endocarditis (Infective Endocarditis)?

Individuals with congenital heart disease (CHD) may be at increased risk of developing an infection inside the heart. There is greatest risk in those with chronic cyanotic heart conditions and/or pulmonary hypertension/Eisenmenger’s syndrome. Other congenital conditions that remain at risk are those with residual defects causing turbulent blood flow through heart chambers and/or areas of surgical repair with artificial materials such as patches or valve replacements.

Extensive review of research by the American Heart Association’s Endocarditis Committee and international experts developed new guidelines for prevention of bacterial endocarditis in 2007.  The new guidelines have also been endorsed by the Infectious Diseases Society of America, the Pediatric Infectious Disease Society, and the American Dental Association.

Previously all people with CHD received antibiotics before dental and invasive procedures to prevent endocarditis. The new guidelines, however, require antibiotics prior to dental procedures only for cardiac conditions associated with the highest risk of complications from endocarditis. You will need to discuss your child’s congenital condition with his/her doctor to determine if your child needs antibiotic prevention.
Note that antibiotic prophylaxis may change if your child has more surgery or any new concern with his/her heart condition. Some of the simple patch or valve repairs only require antibiotics for the first six months after surgery until the artificial material undergoes endothelialization, a process in which natural tissue grows over the artificial material and makes it smooth.

Antibiotic prophylaxis is now recommended only for the following cardiac conditions:
  • prosthetic (artificial) heart valves
  • a previous history of endocarditis
  • congenital heart disease only in the following categories:
  • unrepaired cyanotic congenital heart conditions, including those with palliative shunts and conduits
  • congenital heart conditions completely repaired with prosthetic material or device, whether placed by surgery or catheter intervention, during the first six months after the procedure
  • repaired congenital heart conditions with residual defects at the site or adjacent to the site of a prosthetic patch or device (which inhibit endothelialization)

  • cardiac transplantation recipients with cardiac valvular disease
Consult your child's physician with any further questions you may have about risk factors.

Signs and Symptoms of Bacterial Endocarditis (Infective Endocarditis)

Bacterial endocarditis is most likely to occur in patients who have the following conditions:

  • Aortic Valve Lesions
  • Aortic Coarctation
  • Mitral Valve Prolapse
  • Patent Ductus Arteriosus
  • Tetralogy of Fallot
  • Transposition of the Great Arteries
  • Ventricular Septal Defect
Patients who have successful surgical repair of these heart conditions can greatly reduce their risk of developing bacterial endocarditis.

A common sign of bacterial endocarditis is prolonged fever for two to three days in patients with congenital heart disease, particularly after a dental, intestinal or urinary tract procedure.

Symptoms also may include:

  • Poor appetite
  • Fatigue
  • Joint pain
  • Rash
  • Weight loss

How is Bacterial Endocarditis (Infective 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 to the right), 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. They must be taken before antibiotics are started to determine if you have endocarditis.
  • Echocardiogram (ultrasound of the heart) may show growths, 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 very 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 (Infective Endocarditis) treated?

Specific treatment for bacterial endocarditis will be determined by your physician based on:

  • your age, overall health, and medical history
  • extent of the infection
  • cause of the infection
  • your child's tolerance for specific medications, procedures, or therapies
  • expectations for the course of the infection

After the specific bacteria causing the endocarditis are identified from blood culture tests, a course of intravenous (IV) antibiotic therapy is started. IV antibiotics may be given for as long as 6 weeks to control the infection. Symptoms are monitored throughout therapy and blood tests are performed to determine the effectiveness of treatment.

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

Bacterial endocarditis treatment starts with prevention. Once endocarditis occurs, quick treatment is necessary to prevent damage to the heart valves and more serious complications, such as death. Consult your child's physician for more information.

How can Bacterial Endocarditis (Infective Endocarditis) be prevented?

Traditionally, patients who were considered at risk of developing endocarditis were advised to take antibiotics as a preventive measure before any dental, gastrointestinal or urinary tract procedure. Recently, a group of experts appointed by 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.

Schedule regular doctor's appointments; make immediate appointments if any of the symptoms of endocarditis develop.

Have dental checkups every six months or more often if recommended by your dentist; make immediate appointments for toothaches or abscesses.

Practice good oral hygiene; brush teeth after meals; do not used unwaxed dental floss.
Carry a written medical history and physician's recommendations for antibiotics for use with any dental or invasive procedure.

Call your doctor if you have even a minor infection. Be sure to take the full course of antibiotics prescribed, not just until the symptoms resolve. The antibiotics aren't just treating the infection, they're preventing endocarditis.

Become health-conscious and increase resistance to common diseases: eat right, get adequate rest and exercise, don't smoke, control cholesterol and blood pressure, manage stress, and maintain good personal hygiene. In other words, stay healthy.

Read more: Complications, Clinical Features Of Infective Endocarditis