Rheumatic fever - Causes of rheumatic fever

Most experts believe rheumatic fever is caused by the immune system overreacting to the presence of group A streptococcus bacteria.

Almost all cases develop a few weeks after a throat infection with group A streptococcus bacteria.

During this throat infection, the lining of the throat becomes inflamed as the immune system responds to the infection.

In cases of rheumatic fever, it seems that the process of inflammation spreads throughout your body in an uncontrolled way. The inflammation can affect:

  • the heart, which causes the symptoms of chest painfatigue and shortness of breath
  • the joints, which causes the symptoms of arthritis
  • the skin, which causes the symptoms of the skin rash and nodules
  • the nervous system, which causes the symptoms of chorea (uncontrollable jerking) and the changes in personality associated with rheumatic fever

Exactly why the immune system suddenly stops working properly is unclear. One theory is that the streptococcal bacteria have a similar molecular structure to certain tissues in the body. The immune system targets not only the bacteria, but also tissues sharing a similar molecular structure.

Another theory is that some people may be born with certain genetic factors that make their immune system more likely to malfunction after a throat infection.

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