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What is Myositis?
and Dermatomyositis are related illnesses affecting muscle and connective
tissues of the body. Joints may also occasionally be involved. A rarer
form of Polymyositis is known as Localised Nodular Myositis. Inclusion
Body Myositis is often unresponsive to treatment but is not as aggressive
in the early stages as other forms of Myositis.
Polymyositis, the main problems are weakness and inflammation of
the muscles. (‘Poly’ means many, ‘myo’ means
muscle, ‘itis, means inflammation.)
In Dermatomyositis, the problems are similar
to Polymyositis but also include skin rashes. (‘Derma’
Localised Nodular Myositis is a condition appearing in single muscle
or muscle groups where painful tender lumps can be felt.
Inclusion Body Myositis is usually progressive
and very difficult to treat.
In most of these conditions, the voluntary muscles
undergo degenerative changes due to inflammation. The main symptom
of these illnesses is muscular weakness, which may be progressive
and can be severely disabling. Initially it is not usually painful
in children and noticeable weakness may develop gradually over several
What Causes Myositis
Because Myositis affect individuals differently,
it also probably has many causes. Some doctors think it may be an
autoimmune disease. This means that it is a result of a defect in
the immune system, which is the body’s natural defence against
disease. In healthy people, the immune system produces substances
to attack disease agents such as bacteria and viruses. In people
with an autoimmune disease, there is a defect in the immune system
that causes it to turn against the body’s own tissues. Other
doctors feel it may be started by a virus or the combination of
a viral infection and defective immune system.
What are the Early Symptoms of
These illnesses can vary greatly from patient
to patient, and few cases are identical and follow the same pattern.
Some people may have had the disease for months or even years before
it is noticed. However, the majority find within weeks they have
developed muscular weakness. This is sometimes accompanied by pain
and tenderness especially in adults. The large muscles about the
hips and shoulders are usually the first to be affected. The weakness
results in difficulty in walking, lifting arms and getting up from
the sitting and lying down positions. There may even be some trouble
in swallowing and the voice may become nasal in quality. Other muscles
sometimes affected are those in the neck making if difficult to
raise the head when lying down. Depression and a general feeling
of misery particularly in children, is very noticeable and can be
an indication of the disease before any sign of muscle weakness.
Who gets Myositis and at what age
does it appear?
These illnesses can affect people of any age
and sex. PM and DM affect about twice as many women as men in adult
life. In children the ratio is equal. IBM usually occurs in middle
to later life and is more common in men than women. Although the condition
affects adults and children, the childhood form possibly has different
underlying causes and behaves very differently from the adult form.
Children can be expected to make a complete recovery. However, it
is a rare disease in any of its forms.
Can I catch Myositis from other
No! There is no evidence to suggest it can
be transmitted to other people as an infection. The disease is also
not inherited, and as yet there is no way one can predict who in the
general population will be affected.
How do these illnesses differ?
The muscular weakness in Dermatomyositis is accompanied
by a patchy, dusky red rash, medically termed, an ‘erythematous’
rash. It usually appears over the cheeks, about the eyes, where
it can be violet in colour particularly over the eyelids, on the
neck, shoulder, and upper chest. It can be quite prominent over
the knuckles and elbows and sometimes on the knees and ankles.
Tiny blood vessels may be seen in the skin in
the reddened areas, and the skin may become shiny and tight. In
severe cases the entire skin may take on a reddish hue. There may
also be a degeneration of blood vessels (vasculitis) underlying
the muscle damage and the development of calcinosis especially in
children. This is where there are deposits of calcium salt in the
skin and in the muscle. In the skin these can feel hard and sometimes
can erupt and drain a white, chalky fluid. This may lead to a secondary
infection which will need to be treated with antibiotics. Calcinosis
may require surgical removal of troublesome deposits. This feature
is more common in children.
Polymyositis while defined as an inflammation
of the muscle can also be a feature of a more general autoimmune
illness such as Systemic Lupus Erythematosus, Scleroderma or even
Rheumatoid Arthritis. Other possible symptoms of both illnesses
include fever and weight loss. A few people have an extreme sensitivity
and reaction to cold that is most often felt in the fingers and
toes. The problem is called Raynaud’s phenomenon and is caused
by a narrowing of the blood vessels in the fingers and toes. This
reduces blood flow and turns the fingers and toes white, then gradually
to blue. They may also feel numb and may develop shiny red areas
around and under the nails. In this situation it is very important
to keep hands and feet warm.
There is no association with malignancy in children
and only a weak association with an underlying tumour in adults
How is the Diagnosis made?
doctors at a centre familiar to the disease will recognise the disease
after a simple examination. It will then need to be confirmed by the
measurement of certain blood enzymes and other tests. Blood tests
alone will not confirm the disease particularly in the childhood form.
Examination of the electrical activity of the muscle, known as electromyography,
and in addition a muscle biopsy maybe done which will help make the
diagnosis. This involves a small piece of muscle tissue being taken
and then examined under a microscope.
What is the Treatment for Polymyositis and Dermatomyositis?
Once the disease has been diagnosed most patient
respond well to steroids. The childhood form is very sensitive to
steroids and practically all of them will respond, whereas the adults
are much more variable. A second line of treatment is immunosuppressive
medication. Like steroids these drugs suppress the body’s
immune system and limit the inflammation. These drugs are monitored
under a strict regime, with regular blood tests to monitor their
effect and progress. In children the steroid treatment has to be
carefully tailored as to the child’s needs, as too little
treatment might not adequately suppress the condition. If the patient
did not respond to these treatments then intermittent (pulsed) treatment
can be given intravenously or plasma exchanges would be considered.
Why this Medication?
Steroids are prescribed because they are thought
to be able to ‘modify’ the immune response against tissue.
Immunosuppressants are prescribed because they slow down the immune
system, reducing its ability to attack disease agents or healthy
tissue. The two may be used together with good effect, but the reasons
for this are not fully understood.
Are there Side Effects from these
Steroid drugs and Immunosuppressants are very
powerful agents and can have a number of side effects even when
correctly administered. These can be shown by weight gain, rounding
of the face, increased hairiness, and easy bruising. More serious
side effects such as thinning bones, depression, high blood pressure,
cataracts, bringing on or worsening of diabetes, and in very rare
cases, bleeding from the stomach. These symptoms are rarely encountered
if the disease has been managed correctly, and there has been no
overlap or influence from another illness. The sufferer, because
the immune system has been suppressed, will be open to increased
risk of infection from common ailments they would usually fight
off. Also the way these ailments express themselves may not follow
the normal pattern when these drugs are taken. In children growth
may be restricted.
Can I stop the Drugs if I appear
to feel better?
During the medication by steroids, the body slows
production of its own steroids. For this reason, any time the dose
is to be lowered, the doctor will gradually reduce the level of
steroids a patient is taking, tapering off over a period of weeks
or months. During this time the body will gradually increase its
own steroid production.
How long do I take Drugs for?
Opinions vary among doctors as to how long to
continue treatment but the majority prefer to give drugs for a least
two to three years. During this period regular muscle function tests
are given as a guide to the disease activity and to make sure the
necessary dose of drugs are prescribed to control the disease. The
period of time may need to be longer, although in children this
period can be less if the disease has ‘burnt out’, or
is under control until it goes away. While the disease remains active
the drugs only suppress its activity. As yet there is no totally
satisfactory treatment of myositis which is going to effectively
cure all of the patients all of the time.
What would happen if I refused
this treatment by Drug Therapy?
It is possible that the untreated condition may
stop deteriorating and may even improve. However, usually this is
not the case and muscles may have been permanently damaged and weakened
by inflammation as a result of the lack of medication. The muscles
may even shrink and cause deformity. The untreated illness may even
be severe enough to put the sufferer’s life at risk. Before
the days of steroids and particularly in children the disease carried
an appreciable mortality, mainly as a result of involvement also
of the breathing and swallowing muscles. Approximately a third got
better and about a third might have had some general improvement,
but be left with quite marked disability. The prognosis using modern
treatment is better now. Therefore, treatment at a centre familiar
with these conditions is essential.
How do I live with the illness?
During the active phase of the illness rest is
probably advisable, but once the inflammation has died down active
exercise becomes important, for without exercises the muscles become
weak and wasted. Your doctor, in conjunction with your physiotherapist
will decide at what point to change from resting to active exercise.
The physiotherapist is also very important, as there is a need to
stretch muscles to prevent or limit contractures. Contractures are
a condition where the muscle fibres have become fibrous and loose
their elasticity. This in turn causes a tightness of the muscle
to a degree where joint ranges can become restricted.
Rest is also another aspect that is very important.
During times of increased muscle weakness you need to take frequent
rest periods during the day, and to limit activity to a tolerable
level. As the condition improves and inflammation has died down,
fewer rest periods are needed. Complete inactivity is harmful and
can actually increase muscle weakness. The physiotherapist is invaluable
in advising on an exercise programme to balance rest and activity.
I have Dermatomyositis, what can
I put on the rash to clear it up?
The density of the rash is Dermatomyositis can
vary from the very faint to the severe involvement of the skin.
These can be seen in some case as a very faint hue over the eyelids.
In others it can appear as a type of nettle rash, blisters, or bumpiness.
Sometimes there can be redness and scaling of the scalp. These conditions
are not always permanent and can be treated with topically applied
steroids. The more severe the rash the stronger the strength of
the steroid cream. Regular baths using oily creams or emollients
are advisable, for these will cleanse the skin without removing
the natural oil layer. Detergents must be avoided, even ‘simple
It is also advisable to remember that in
suffering from Dermatomyositis you keep out of harsh, bright sunlight
for long periods. Firstly it can effect the medication and secondly,
the skin, because of the nature of the disease, becomes very sensitive
to the effects of direct sunshine. When going on holiday it is advisable
to use a total sun-blocking agent.
If the Disease does go, will it
There is always a possibility that this can happen.
As it is not fully understood how the disease developed initially,
it can be triggered off again. In women there is always a slight
chance that there could be a flare up because of hormonal changes
particularly in pregnancy and a medical opinion should he sought
before this is envisaged. This can also apply when deciding to take
Can a Diet help?
Some sufferers have found by following a diet
and eating certain foods it has been beneficial to their general
condition. As yet there is not medical proof to support any claims
that diet plays a big role in controlling the disease. However,
a balanced, healthy diet containing fresh food etc., low in saturated
fat and supplemented in certain kinds of fish oil can to a degree
What is my future?
Children may expect their symptoms to go away.
In adults a small percentage do get well within two years. For most
it is a case of living with the disease and understanding as much
about your illness as possible, so that even during the periods of
increased pain and weakness a nearly normal life can be led. It cannot
be denied that it is a chronic illness but the disease is rarely fatal,
and as long as the prescribed medication is taken the future is always
Will I end up in a wheel chair?
Some patients may well need a wheel chair
from time to time. Other equipment such as callipers or splints may
be needed while the illness is at its height. An unfortunate few may
even need more permanent help if there is serious damage of the muscles.
Is there any Research into these
Research directed with an emphasis on all
forms of myositis is very limited. However, the Support Group is currently
funding research projects in London, Manchester and Bath.
The Support Group funds research in various
ways and has spent over £320,000 on Myositis projects.