What is Acute Rheumatic Fever?
Acute rheumatic fever is an illness caused by an autoimmune response to a bacterial infection with group A streptococcus, commonly called the strep bacteria. Infection with group A streptococcus can cause many illnesses, including sore throat (strep throat) and skin sores. In some cases, the immune system gets confused when reacting to the infection and the result is a generalised inflammatory illness that is called acute rheumatic fever (ARF).
ARF affects the heart, joints, brain and skin. The acute episode can last for several weeks with significant joint pain, fevers and other symptoms requiring hospitalisation. The symptoms of ARF typically leave no lasting damage to the brain, joints or skin. However the damage to the heart valves may remain once the episode of ARF has resolved. This is known as rheumatic heart disease (RHD). Recurrent strep infections and episodes of ARF cause further damage to heart valves.
What are the symptoms of acute rheumatic fever?
The most common symptoms of acute rheumatic fever are:
- Joint swelling and pain: This may include redness and warmth, mainly of the larger joints like the knees, ankles, wrists and elbows
- Fever: Hot and cold fevers which may feel like symptoms of a cold or flu
- Sydenham’s Chorea: Jerky, uncontrollable movements called chorea
- Erythema marginatum: A rare skin rash, mainly found on the trunk of the body (this is a very a rare symptom)
- Subcutaneous nodules: Round, painless nodules over the elbows, wrists, knees, ankles and areas near the spine (also very rare)
- Heart problems: Swelling of the heart may cause chest pain, and if severe there may be signs of heart failure (breathlessness, swollen legs and face).
Not all people with ARF have all of the symptoms; however people with ARF are often quite unwell and require hospitalisation.
Who is at risk?
Currently, Australia has among the highest recorded rates of ARF and RHD in the world, and it‘s a significant cause of disease among Aboriginal and Torres Strait Islander children. Aboriginal and Torres Strait Islander people living in rural or remote settings, particularly across central and northern Australia, are known to be at high risk. Other Aboriginal and Torres Strait Islander people living in urban settings, as well as some immigrants from developing countries may also be at high risk.
First episodes of ARF are most commonly seen in children 5 to 14 years old although people can have recurrent episodes into their forties. It is more common in females than males. A person’s risk of an episode of ARF is thought to be a combination of three factors:
Environmental conditions associated with exposure to the strep bacteria, particularly overcrowded housing. The strep bacteria is spread through mucous and other bodily fluids so it is easily spread from one person to another, especially by breathing or coughing on others.
Genetics of an individual seem to play a role. There is not yet any evidence that rheumatic fever runs in the family. However, it is not uncommon for more than one person in a family to have had rheumatic fever. A study exploring genetic risk of developing RHD is underway.
Only some strains of group A streptococcus are ‘rheumatogenic’. In other words, some types (strains) of strep bacteria are more likely to cause ARF than others.
Not all people who have a streptococcal infection develop ARF but those who have had ARF are at high risk of getting it again.