JM Treatment

This is a difficult question to answer. 10 years ago, we certainly used steroids for longer periods of time, and were less likely to use second line agents (particularly methotrexate) than we are now. Many rheumatologists would now have chidren with myositis off steroids in 9-12 months (assuming a good response), and most would start methotrexate at the beginning of treatment. The hope is that outcomes are just as good, but with a reduction in steroid side effects. I think there is some early evidence that this is true, but probably not enough to be certain. There are some new mediations (like Rituximab), but there role and effectiveness remains to be proven.

In my experience, and that of many of my colleagues, IVIG can be an extremely effective medication. I tend to use it is patients who are responding slowly at the start of therapy, or look at thought there may be a fairly severe course. It can also be extremely effective for chronic skin disease. Finally, I will often use it as an alternative to increasing steroids when there is a flare of disease. The biggest problem with IVIG is access (both the need for IV access, and cost issues). For some children, headache and/or nausea can also be limiting.

The issue of cancer in myositis is quite clear in adults-and there is definitely an association. However, the strength of that association is probably not as strong as has been reported at some times—up to 1/3 has been often quoted. However, more recent statistics have suggested that the actual percentage is less—likely closer to 10%. The issue in pediatrics is considerably more complicated. There have been a very small number of case reports of children with myositis syndromes have cancer. In fact, the numbers are so small that it is likely that there is not an association of childhood myositis with cancer. In general, children are not screened for cancer, beyond routine bloodwork. This is partly related to the low likelihood of there being a cancer to find, and partly to the types of cancers we see in children (e.g. leukemia is much more common, and is picked up on fairly routine bloodwork that we would do in any patient).

There is no evidence that myositis causes cancer, although in truth, it is difficult to say which develops first—the myositis or the malignancy. It is also possible that some third process, as yet unknown, leads to both.

The literature on predictors of permanent damage is somewhat limited. There are some factors which have been associated quite consistently–in particular late/delayed treatment and indadequate treatment (not enough steroid or too brief steroid). Some of this was described back in the 1980’s–the impact of new approaches (such as starting second line agents like methotrexate at diagnosis) is unknown. There is also some recent data suggesting that features of the muscle biopsy can predict poor outcomes, but this is quite preliminary. Otherwise, it is quite difficult to predict the course, and therefore the outcomes, for children with myositis. However, in the next year or so, there will be some publications (both from the European group and the North American group) which may help to answer this question to a more satisfactory degree.

This is a surprisingly difficult question. Some series have shown rates of calcinosis that were quite high (up to 40%). However, in other clinics, it is clear that calcinosis is quite uncommon. In our clinic, calcinosis appears to be quite rare. We do not understand the factors that lead to calcinosis particularly well–there are probably genetic factors as well as environmental ones. It has been suggested that chronic skin disease increases the risk of calcinosis (based on MRI studies). It is also likely that delayed/inadequate therapy increases the risk. However, the variation in calcinosis rates is not explained by differences in treatment. I am not sure if this is a very satisfying answer, but is probably the best we can do in 2010. As you can appreciate, the prevention of calcinosis is an important goal of myositis treatment, given that there is little effective therapy.

It is difficult to make any concrete response to this question, although it certainly is a good question. We certainly see some patients respond very rapidly (within 1-2 weeks), and others seem to take substantially longer (8 weeks or longer). I would certainly prefer to see some evidence of response (or at least an arrest of any deterioration) within 4-6 weeks, and hopefully sooner. It is important to keep in mind that there is some good evidence from Dr. Pachman in Chicago that steroids by mouth may not be absorbed very well in children with active myositis, which could delay response–in that case, the use of IV steroids may be better.

I am fortunate in that our clinic (for whatever reason–I don’t think it is my superior care) has very little calcinosis. At this point, I have not been convinced that there is any effective treatment for calcinosis–there have been many reports of a variety of medications, but none have been very convincing. Assessment of any therapy is complicated by the fact the calcinosis sometimes clears on its own, without intervention.
I think there are definitely circumstances where surgery is useful-if the area is particularly vulnerable (on a joint), or causing dysfunction or pain. It is reported that the surgery can stimulate the calcinosis to grow back, although I have seen cases where this was not the case. I think it is very important to have the disease under good control when the surgery is done to minimize the risk of recurrence. Finally, the most important treatment for calcinosis is to prevent it in the first place.

The injected flu vaccine should be safe for children with myositis, being treated with immunosuppressive medications. In general, vaccines that are not “live” should be safe, which includes most vaccines. The flu vaccine which is inhaled (a mist up the nose) is actually a live virus, weakened, and probably should not be given to a child on steroids or other immune suppressing medications. Other live virus vaccines include mumps/measles/rubella, chicken pox, as well as few rare ones given if children are travelling.

There are a couple of potential issues that bear comment. First, being on immune suppressing medications like prednisone may mean that a child does not respond to the vaccine (ie. is not protected). Second, the illnesses that we vaccinate against have the potential to be very serious in someone who is immune suppressed (like on steroids)–we immunize all our patients with myositis to provide whatever protection we can. Finally, there is a theoretic risk that an immunization could stimulate the immune system, leading to a disease flare. This is not proven, and is probably equally likely if a child gets an infection. Our general policy has been to vaccinate and protect our patients, and deal with any flares if they occur. We have not seen any convincing flares in this circumstance.

This is a common problem, and not one that has any easy answers. Prednisone really is a double-edged sword. We need the positive effects on the disease, but really hate the side effects. There is not much that is hugely helpful. We have all our patients work with a dietician to minimize weight gain as best we can. A psychologist can be helpful to deal with some of the behavioural issues, and assist with strategies to deal with the sometimes overwhelming hunger (and help with issues around having a chronic illness, changes in appearance etc).
In the end, the best thing you and your doctor can do is to reduce the prednisone as quickly as is safe. I agree that the side effects can often be miserable, and may even feel worse than the disease.

You raise a really interesting question. Definitions of terms like “remission” are not always consistent. I think the most commonly used definitions of remission now include “off medications”. For that reason, I would hesitate to use the term remission for someone still on 5 mg of prednisone. However, you MIGHT be in a true remission. By this I mean it is impossible to know right now if you are doing well because your JDM has gone away (remission), or if it is because the little bit of steroid is controlling it very well.

The only way to know is to continuing weaning the steroid, carefully and with regular evaluations. Suddenly stopping the steroid could be dangerous–both becuase of the possibility of a disease flare and because your body needs to time to start making its own steroid, and suddenly stopping steroid would not allow this to happen. This is certainly something you should discuss with your doctor.

Not to the best of my knowledge, although I can’t say that this is my area of expertise.

At this point, we have some genes that are associated with myositis in children, although I think it is premature to say that we “know” the cause. There are some genes in a very important area called HLA that seem to increase or decrease the chance of developing myositis. There is also a gene polymorphism (a slight difference in the gene that is quite common in the population) in a gene called TNF-alpha which seems to increase the chances of developing JDM. There are probably many other genes that predispose to developing myositis–it is likely that several are needed, and probably some sort of trigger (an infection maybe) for a child to develop myositis.

There is little evidence that your ability a child is affected by having myositis. It is possible that a flare could occur, as there are fairly major changes that occur in the immune system during pregnancy. From a safety point of view, your myositis would ideally be in complete remission (ideally off medications), and you would want to be carefully monitored during the pregnancy, both for your health and that of your baby.

It is possible that certain medications could affect your ability to become pregnant (mainly if your disease was severe enough to require cyclophosphamide). As well, some medications that you may still be on could have bad effects on a baby (methotrexate for example).

The likelihood of your children developing myositis or another autoimmune illness is probably slightly increased. However, this risk is still very small, and it remains much more likely that your children will not be affected.

There have been several studies which have looked at infections–most have suggested a variety of possible triggers. My reading of this literature is that infections of many kinds may act as a trigger for myositis in someone with the right genetic predisposition.
There is not much else to report regarding toxins, poor diet etc and true myositis. There have been some mimics of myositis (eg. contaminated tryptophan supplements causing myositis), but these are probably not quite the same thing.

I think that this question is a little bit different in each area where it is a problem. I think there are a few issues–first, most of the illnesses that pediatric rheumatologists deal with (except for arthritis) are rather rare. Often, institutions/funding bodies etc find it difficult to justify a pediatric rheumatologist for their population. Unfortunately, another issue is often that pediatric rheumatolgists are relatively expensive–by this I mean that we typically take a long time to see patients (so low billings), order a lot of expensive tests, and do not do much in the way of procedures that generate cash flow. This may be a somewhat cynical view of things, but I do think that sometimes it comes down to money. Finally, one of the problems is definitely the rarity of most of our illnesses–it is difficult to support a pediatric rheumatologist outside a major centre–without a large population, there simply isn’t that much work to do.

I don’t think that this is a very satisfying answer, and certainly one that many of my colleagues in the US (and elsewhere) are continually worried about. I consider myself very fortunate to live in Canada where I think the access to pediatric rheumatology is rather good, at least in the urban centres.

We know that autoimmune diseases “run in families”. For example there is a higher risk of a variety of things if family members have something like myositis or rheumatoid arthritis. However, the increase in risk is relatively small, and it remains much more likely that your child with NOT have an autoimmune disease (and if they do develop something, it might be myositis–rather it could be autoimmune thyroid disease, rheumatoid arthritis etc)

We don’t have very specific answers to this question. I think you are very correct that most children who have had JDM do very well, and often have sequelae-free outcomes.

There are probably few recommendations that can be made to help them to stay that way. I do continue to recommend continued sun-protection (which is probably relevant to all of us anyway).Otherwise, continued healthy living is as good as we can do–regular exercise, healthy diet, and routine health monitoring (bone health, cholesterol etc). There are not specific activities/dietary factors etc that we know of that can prevent future flares.

As with many of the questions this afternoon, I don’t think we know what to recommend. Certainly, following treatment recommendations is probably the most important thing that families can do–the worst calcinosis patient I have ever seen was a family to had great difficulties following the recommended treatment course, and were lost to follow-up for several years.

I suspect that appropriate sun-protection is also important. We know from some basic science work that sun exposure can stimulate immunologic processes, which could theoretically contribute to calcinosis.