Rheumatic Fever is one of those illnesses that used to be rampant in the past but is very rare now (although still a major problem in some parts of the world).

It’s called “rheumatic” because joint pains and arthritis were one of main features of the illness.

The reason it’s important for Sydenham’s chorea is that chorea (a particular kind of movement disorder) is another main feature of the same illness, although less common than arthritis.  So you can have rheumatic fever with Sydenham’s chorea – but you can just have Sydenham’s chorea, without other features of rheumatic fever.

Both are caused by the body’s immune system attacking itself, following an infection with the bug Group A Streptococcus (also called Streptococcus pyogenes, or strep for short). 

If you develop Sydenham’s chorea, it’s really important to get an echo of the heart, even if there isn’t any obvious heart problem.  That’s because heart damage is the most important long term complication of rheumatic fever. And it’s possible to stop it getting worse, with long term antibiotics.

There are some other clues that you might have rheumatic fever – nodules appearing under the skin, abnormalities on ECG (electrocardiograph, or heart tracing), a dramatic rash (erythema marginatum).