Rheumatic fever is an illness caused by a particular type of germ called beta-haemolytic streptococcus. It is the same germ that can cause a really sore throat. It can affect your heart, as well as your joints, skin and nervous system.
What is rheumatic fever?
Rheumatic fever is caused by your immune system overreacting to a germ (a bacterium). It starts with a bad throat infection (what some people call 'Strep throat'). A few weeks later you get sore joints: it could be your knees, elbows or wrists. The soreness comes and goes.
The initial effects of rheumatic fever aren't in themselves too harmful. The problem is, the illness can involve your heart. The covering of the heart (the pericardium) can get inflamed, and the valves inside your heart that make the blood flow in the right direction can get damaged.
Occasionally the illness can make you have very weird jerky movements called chorea.
What is the cause of rheumatic fever?
The disease starts with a throat or skin infection with a particular germ (bacterium) called a Lancefield group A beta-haemolytic streptococcus.Usually this bug just causes a really sore throat or a bad skin infection which can be easily treated with the antibiotic penicillin.
For most people that is the end of the problem but in rheumatic fever your immune system overreacts. Your immune system thinks it can recognise bits of the streptococcus bug in your joints, heart and nervous system and so attacks them.
Who gets it?
Until about the mid-1900s rheumatic fever was found in the UK and other western countries. But since antibiotics have become widespread it has practically disappeared from the UK. In Africa, India and rural parts of Australia and New Zealand people still get rheumatic fever: roughly 1 in 300 teenagers will get it each year in those areas.The disease is mainly related to a lack of antibiotics and also to poor social conditions like overcrowding.
The main age range is 8-14 years, with a peak age of 10 years old. Girls are slightly more likely to develop rheumatic fever than boys.
How do doctors diagnose rheumatic fever?
The diagnosis is usually made by the history of a sore throat or a bad skin infection followed, a few weeks later, by the typical features and symptoms. A blood test to show a recent infection with the streptococcus bacterium (called an antistreptolysin titre) can help to confirm that the bacterium has been in your body.
But then there is a scoring system using major criteria and minor criteria. You need two majors, or one major and two minors, to make the diagnosis.
- The major criteria are the main symptoms:
- Joint pains.
- Heart problems.
- Jerky movements (called chorea).
- Skin problems.
- The minor criteria are:
To see the problems on the heart, a specialist will usually use an echocardiogram: a special scan to see the inside of the heart. But in many parts of the developing world there are not echocardiograms available.
Which parts of the body are affected by rheumatic fever?
Rheumatic fever can affect the joints (like your knees, elbows and wrists), the heart, the nervous system (your brain) and sometimes the skin.
How does rheumatic fever affect the joints?
- Some joints become hot and red and are sore to move.
- The knees, wrists, elbows and ankles are affected.
- The pain and redness may come and go: some joints will get better then others will get worse.
- Usually only two joints are affected at the same time.
- Each joint is usually affected for a few hours to a few days, before improving.
What problems does rheumatic fever cause in the heart?
- It causes something called 'carditis': this is an inflamed heart.
- It can also inflame the covering of the heart and cause something called 'pericarditis'.
- Or the heart muscle itself, causing myocarditis.
- Or the little valves inside the heart, causing endocarditis.
- This can give you pains in the chest, breathlessness and a fast heart rate.
How does rheumatic fever affect the nervous system?
In about a quarter of people with rheumatic fever they develop strange, jerky movements called 'chorea'. They usually last a few weeks and then fade away, but in a few cases can go on for months. The movements usually settle down when the person sleeps.
What changes can be seen in the skin with rheumatic fever?
Skin problems only affect about 10% of people with rheumatic fever. They can be tiny bumps under the skin (called subcutaneous nodules). Some people get pale red patches on their arms and tummy (called erythema marginatum).
These skin problems are not serious and they fade away once the rheumatic fever goes away.
What are the treatments for rheumatic fever?
The treatment depends on which part of the body is affected.
- For the joint pains, usually aspirin or ibuprofen is sufficient. They settle in a few weeks.
- For heart problems, a specialist doctor may need to prescribe medicines that relieve the strain on the heart. These are medicines like 'water' tablets (diuretics), angiotensin-converting enzyme (ACE) inhibitors and digoxin. Sometimes the damage to the heart valves is so bad that urgent heart surgery is needed.
- The jerky movements (chorea) are sometimes difficult to treat. Generally sedatives are used like diazepam. If the chorea is very severe and lasts several weeks then specialist procedures like plasmapheresis are used: this is a way of 'cleaning' your blood by pumping it through a special machine and back into your body.
- Usually the antibiotic penicillin is given for ten days to make sure that none of the original bacterium, the streptococcus, is still in the body.
- If the heart problems are particularly bad, some people recommend penicillin until the age of 21 years at least.
- Rheumatic fever is one of the few conditions where bed rest is recommended, even if the person feels well enough to be up and about. They should rest until the blood tests for inflammation return to normal.
What is the outlook for someone who has had rheumatic fever?
Generally the symptoms of the fever, joint pains, heart problems and chorea fade away by about three months in most people. Very occasionally the chorea goes on for years but this is very rare.
The main long-term problem is with the heart. About a third of people who have had rheumatic fever will get long-term problems with their heart. This is then called rheumatic heart disease. It can damage the heart permanently and require lifelong medication or even surgery to the heart valves many years later.
Further reading and references
Patient-friendly guide to rheumatic fever; Mayo Clinic