A classic case of JDM
Published on 01 April 2008
Research is shedding new light on a rare but often serious muscle disease affecting children and teenagers. Jane Tadman reports on Arthritis Research UK’s latest research into juvenile dermatomyositis.
Louise Wyatt at her parents' farm near Chard, Somerset.
When Louise Wyatt started to feel tired just after her 15th birthday doctors diagnosed a virus and gave her pills. But instead of getting better the previously fit and healthy teenager – who regularly helped out on her parents’ farm – started feeling more and more exhausted.
“It was like I’d just run a marathon – and I felt like that all the time,” recalls Louise, now 18. Three months later, she was seen at her local hospital, and just as she was about to see a rheumatologist, her condition deteriorated further.
“I could hardly walk up the stairs, get changed, get in or out of the bath or even feed myself because my muscles were so weak,” adds Louise. “I didn’t like to go out in case someone knocked me and I might fall over. It was really depressing, and looking back, very scary.”
Fortunately paediatric rheumatologist in Bristol, Dr Athimalaipet Ramanan, knew straight away that Louise was suffering from juvenile dermatomyositis (JDM), a rare, inflammatory form of muscle disease in young people, which can also affect the skin, joints and internal organs. In fact so typical was her condition that he told her she was a “classic case.”
The teenager spent a week in hospital in Bristol undergoing a battery of tests including full body scans, x-rays and blood tests.
“I’d never been ill before and in one week all this was thrown at me,” says Louise, “Luckily my mum was with me all the time, and as we live on a farm we looked on it as having a little holiday!”
Louise was started on steroid injections and methotrexate which made a big difference immediately. Although she still felt tired, her condition stabilised. Twice a week her mum took her for hydrotherapy and later physiotherapy sessions in nearby Taunton, which played a big part in her regaining some muscle strength.
"I was so glad to get back to normality"
It was another 2 years before her condition really improved to her consultant’s satisfaction. Louise’s care was recently transferred to an adult rheumatology service in Yeovil and although she is still on methotrexate her dose is slowly being decreased.
“I now feel quite all right. I will never be back to normal as I’ll never have the stamina but I can now do lots of stuff – such as shopping! It was very tough though. It was hard because my parents needed help on the farm and my sister was only 12 so couldn’t do some of the things I used to do.”
Inevitably Louise missed a lot of school and in the early stages of her illness could only manage to attend for half the school day. But she’s now well enough to be taking her A levels this year and has a real chance of realising her ambition of going to Bournemouth University to study illustration. “Drawing was one of the things that kept me occupied, and the thing that kept me going when I was ill – although sometimes I was too weak to hold a pencil and couldn’t move my wrists properly.”
Louise’s illness has made her appreciate normal things. She adds: “It made me appreciate school – believe it or not! I was so glad to go back, to get back to normality.”
There are many difficulties facing researchers investigating juvenile dermatomyositis. The name hardly trips off the tongue for one thing. For another, not many people have heard of it. Plus, there’s not a great deal known about what causes it.
Maybe the challenge of finding out more about this form of inflammatory muscle disease (it affects only a few hundred children and teenagers in the UK) is what has prompted the formation of a dedicated body of interested Arthritis Research UK researchers. Research was certainly given a major boost in 2000 when Dr Lucy Wedderburn and a team at the Institute of Child Health in London set up a national collection of clinical information and blood samples from children being treated around the country. The JDM National Registry and Repository is now a major resource for researchers investigating disease, with now just over 250 children recruited.
Another leading centre involved in JDM research is the Royal National Hospital for Rheumatic Diseases (RNHRD) in Bath, where Professor Neil McHugh leads an academic rheumatology team in collaboration with Dr Wedderburn’s unit. The RNHRD, Bath has a close working relationship with the nearby Bristol Royal Hospital for Children, which offers specialist treatment for JDM, led by paediatric rheumatologist Dr Athimalaipet Ramanan.
The latest young researcher to declare an interest in JDM research is Dr Harsha Gunawardena, based at the RNHRD, who was recently awarded a year-long Arthritis Research UK Barbara Ansell Fellowship to find out more about how abnormal mechanisms of the immune system may play a major role in the disease’s development. The immune system can produce proteins called autoantibodies which target specific parts of the body’s own cells. This is a major feature of the connective tissue diseases. However, previously autoantibodies in JDM have not been identified in much detail.
New antibodies may be predictors of more severe disease
Some preliminary work from the RNHRD group in collaboration with the JDM registry found that specific new autoantibodies are associated with specific clinical features and importantly they may be markers (ie predictors) of more severe disease.
Specialist registrar Dr Gunawardena now aims to take the work forward by investigating the importance of these autoantibodies in all JDM patients recruited on the registry.
“We aim to investigate the relationship of these different autoantibodies in JDM, and using some exciting lab techniques we might also find further new autoantibodies that are clinically important,” he says.
“If we can start testing for these autoantibodies routinely, then I hope in the future we will be able to predict how the disease will pan out. This will help guide doctors in monitoring for different complications and prescribing appropriate treatments. So it has huge clinical application.”
Until quite recently it was believed that the adult and juvenile forms of dermatomyositis were similar. But although they are both treated with similar drugs, there are in fact differences. Affected youngsters are more likely than adults to gut inflammation, ulcers and a condition called calcinosis, where deposits of calcium are found in the body’s soft tissue, sometimes in the buttocks. However, children do not seem to develop cancer associated with dermatomyositis, unlike their adult counterparts.
Dr Gunawardena believes specialists are becoming more adept at spotting the disease at a relatively early stage and this will be made easier by finding specific markers in the blood. As with most inflammatory, autoimmune diseases, the convention now is to treat it early and aggressively with medication to get on top of disease and get under control.
What is juvenile dermatomyositis?
- It’s an autoimmune disease that affects the muscle, skin, joints, lungs and gut and blood vessels in children and teenagers.
- It typically starts with a rash, muscle weakness, along with tiredness and mood change.
- It is most common in children aged between 5 and 9, although it can start at any age.
- It is treated with steroids, methotrexate, ciclosporine, cyclosphosphamide, azathioprine and latterly anti-TNF therapy. Physiotherapy is also an important part of the treatment regime.
- It is similar to, but also different from, the adult form of the condition, dermatomyositis.
- Once it is brought under control by medication, many affected youngsters can lead a fairly normal life.