Polymyositis
Polymyositisis an uncommon disease that causes inflammation in your muscles.
It's a type of connective tissue disease. The most noticeable characteristic of
polymyositis is muscle weakness, especially in the muscles closest to your trunk,
such as your shoulder and hip muscles. As a result, you may find it difficult to get
out of chairs, climb stairs, brush your hair or work with your arms over your head.
Polymyositis can occur at any age, but it mostly affects adults in their 40s and
50s. It's more common in blacks than in whites, and women have it more often
than men do. Polymyositis usually develops gradually over weeks or months.
Periods of remission, during which symptoms improve spontaneously, rarely
occur in polymyositis. However, treatment can improve your muscle strength and
function.
Symptoms
Signs and symptoms of polymyositis usually appear gradually, so it may be
difficult to pinpoint when they first started. They may also fluctuate from week to
week or month to month. The most common polymyositis symptoms include:




Progressive muscle weakness, particularly in the muscles closest to the
trunk, such as those in your hips, thighs, shoulders, upper arms and neck.
This weakness is symmetrical, affecting both the left and right sides of your
body.
Difficulty swallowing (dysphagia).
Mild joint or muscle tenderness.
Fatigue.
Causes
Your immune system
Polymyositis belongs to a group of conditions called inflammatory myopathies.
Myopathies are diseases or abnormal conditions of the muscles. The cause of
most inflammatory myopathies is unknown. Infections caused by bacteria,
parasites or viruses can cause inflammatory myopathies, but in most cases,
doctors aren't able to identify a preceding infection in polymyositis.
A disease similar to polymyositis is dermatomyositis. Dermatomyositis leads to
many of the same symptoms as polymyositis, but it causes skin inflammation or
a rash as well. Some other inflammatory muscle diseases are: inclusion body
myositis, which progresses more slowly than other forms; myositis associated
with other connective tissue diseases, such as lupus or scleroderma; and
myositis associated with cancer.
Immune system plays role
Doctors suspect that myopathies are autoimmune disorders, in which body's
immune system mistakes normal components of body for foreign substances and
attacks them. If you have polymyositis, an unknown cause seems to trigger
immune system to begin producing autoimmune antibodies (also called
autoantibodies) that may damage healthy body tissues. Many people with
polymyositis show a detectable level of autoantibodies in their blood. It's still
unclear, however, whether these autoantibodies are indeed involved in causing
polymyositis.
Polymyositis has also been associated with several viral diseases, including HIV.
Some researchers speculate that, in some form, polymyositis may be caused by
a viral infection of the muscle. This theory isn't well supported,.
Tests and diagnosis
Diagnosis of polymyositis isn't always easy and can be a lengthy process. Even
though the attempt to diagnose your condition may be frustrating, remember that
an accurate diagnosis is necessary to receive appropriate treatment.
In addition to a thorough physical exam, including assessment of muscle
strength, doctor will likely use some or all of the following information and tests to
assist in the diagnosis:

Family medical history. A careful history of muscle disease in family
and age at onset of the disease will help doctor distinguish between
polymyositis and muscular dystrophy. Muscular dystrophy is an inherited
condition; its signs and symptoms usually begin in early childhood.

Electromyography. A thin needle electrode is inserted through skin into
the muscle to be tested. Electrical activity is measured as you relax or
tighten the muscle. Changes in the pattern of electrical activity can confirm
a muscle disease. The distribution of the disease can be determined by
testing different muscles.

Blood analysis. A blood test can let your doctor know if you have
elevated levels of muscle enzymes, such as creatine kinase (CK) and
aldolase. Increased CK and aldolase levels can indicate muscle damage.
A blood test can also determine whether autoantibodies are present in your
blood. In some cases, specific types of autoantibodies have been
associated with certain signs or symptoms of the disease, such as skin or
lung involvement, and with how the disease responds to treatment.
Knowing whether you have these autoantibodies may help doctor
determine the best treatment plan.

Muscle biopsy. A small piece of muscle tissue is removed surgically for
laboratory analysis. A muscle biopsy may reveal abnormalities in muscles,
such as inflammation, damage or infection. The sample also can be
examined for the presence of abnormal proteins and checked for enzyme
deficiencies.

Magnetic resonance imaging (MRI). A scanner creates cross-sectional
images of muscles from data generated by a powerful magnetic field and
radio waves. These images can be viewed from any direction or plane. MRI
scans may help detect inflammation in your muscles.
Monitoring risk of infections
People with polymyositis may also be at an increased risk of infections,
particularly respiratory and digestive infections
Complications
these complications of polymyositis:

Difficulty swallowing. If the muscles in esophagus are affected, may
have problems swallowing (dysphagia), which in turn may cause weight
loss and malnutrition.

Aspiration and pneumonia. Difficulty swallowing may also lead to
entrance of food or liquids, including saliva, into lungs (aspiration), which
can lead to pneumonia.

Breathing problems. If your chest muscles are involved, may
experience breathing problems, such as shortness of breath.

Calcium deposits. Late in the disease, particularly if the disease for a
long time, deposits of calcium can occur in muscles, skin and connective
tissues (calcinosis).
Polymyositis is often associated with other conditions, including:

Other connective tissue diseases. Diseases such as lupus, rheumatoid
arthritis, scleroderma and Sjogren's syndrome can occur in combination
with polymyositis.

Cardiovascular disease. The muscle of heart may become inflamed
(myocarditis). In a small number of people who have polymyositis,
congestive heart failure and heart arrhythmias may develop.

Lung disease. A condition called interstitial lung disease may occur with
polymyositis. Interstitial lung disease refers to a group of disorders that
cause inflammation and scarring (fibrosis) of lung tissue, making lungs stiff
and inelastic. Signs and symptoms include a dry cough and shortness of
breath. In the late stage of lung disease, high blood pressure in the
pulmonary arteries (pulmonary hypertension) can occur and can lead to
right-sided heart failure.

Cancer. Cancer may be more common in people with polymyositis, but
the evidence for this association is more pronounced in dermatomyositis.
Concerns during pregnancy
Pregnancy may worsen signs and symptoms in women whose disease is active.
Active polymyositis can also increase the risk of premature birth or stillbirth. If the
disease is in remission, the risk isn't as great
Treatments and drugs
Although there's no cure for polymyositis, treatment can improve your muscle
strength and function. Treatment begun early in the disease process tends to be
more effective, often because there are fewer complications. Therapies include
the following:

Corticosteroids. These medications suppress immune system, limiting
the production of antibodies and reducing muscle inflammation.
Corticosteroids, especially prednisone, are usually the first choice in
treating inflammatory myopathies, such as polymyositis.
doctor may begin with a very high dose then decrease it as your symptoms
improve. Improvement generally takes about two to four weeks. Significant
results are usually evident within three to six months, but therapy is often
needed for years.
Prolonged use of corticosteroids can have serious side effects including
osteoporosis, weight gain, diabetes, increased risk of some infections,
mood swings, cataracts, high blood pressure, a redistribution of body fat
and muscle weakness. As a result, your doctor may also recommend
supplements, such as calcium and vitamin D, and may prescribe
bisphosphonates, such as alendronate (Fosamax) or risedronate (Actonel),
to counteract loss of bone density.

Other immunosuppressants. If your body doesn't respond adequately
to corticosteroids, your doctor may recommend other immunosuppressive
drugs, such as azathioprine (Imuran) or methotrexate (Rheumatrex). Your
doctor may prescribe these alone or in combination with corticosteroids.
When in combination, these additional immunosuppressants can be used to
lessen the dose and potential side effects of the corticosteroid.
Immunosuppressants, such as cyclophosphamide (Cytoxan) and
cyclosporine (Neoral, Sandimmune), may improve symptoms of
polymyositis and interstitial lung disease.

Physical therapy. A physical therapist can show various exercises to
maintain and improve your strength and flexibility and advise an appropriate
level of activity. Your exercise program is likely to change during the course
of the disease and treatment period. Staying active will help maintain
muscle strength.
Polymyositis treatments that are still under investigation include:

Plasmapheresis. This treatment, also called plasma exchange, is a type
of blood cleansing in which damaging antibodies are removed from your
blood.

Radiation therapy. This involves irradiation of the lymph nodes to
suppress your immune system.

Intravenous immunoglobulin (IVIg). This involves receiving
intravenous infusions of antibodies from a group of donors over two to five
days. This treatment is usually expensive. It may be an option for you if
your dermatomyositis is severe or resistant to other forms of therapy.

Fludarabine (Fludara). This agent prevents the development and growth
of malignant cells.

Tacrolimus (Prograf). This transplant-rejection drug may work to inhibit
the immune system. Tacrolimus is often used topically to treat
dermatomyositis and other skin problems.

Monoclonal antibodies. These man-made antibodies are designed to
target and destroy specific types of cells. infliximab (Remicade) and
rituximab (Rituxan) on both polymyositis and dermatomyositis
Dermatomyositis
Dermatomyositisis an uncommon disease marked by muscle weakness and a distinctive
skin rash. It's a type of inflammatory muscle disease — "myo" means "muscles" in
Greek; "itis" means "inflamed." "Derma," which means "skin," refers to the skin-related
symptoms that accompany the muscle inflammation of dermatomyositis.
Dermatomyositis may occur at any age, but it mostly affects adults in their late 40s to
early 60s or children between 5 and 15 years of age. Women have dermatomyositis
more often than men do. Dermatomyositis usually develops over weeks or months.
Periods of remission, when symptoms of dermatomyositis improve spontaneously, may
occur. Treatments can improve your skin and your muscle strength and function.
Symptoms
The most common signs and symptoms of dermatomyositis include:

A violet-colored or dusky red rash, most commonly on your face, eyelids,
and areas around your nails, knuckles, elbows, knees, chest and back. Affected
areas are typically more sensitive to sun exposure.

Progressive muscle weakness, particularly in the muscles closest to the
trunk, such as those in your hips, thighs, shoulders, upper arms and neck. This
weakness is symmetrical, affecting both the left and right sides of your body.
Other dermatomyositis symptoms that may occur include:






Difficulty swallowing (dysphagia)
Muscle pain or tenderness
Fatigue, fever and weight loss
Hardened deposits of calcium under the skin (calcinosis), especially in children
Gastrointestinal ulcers and infections, also more common in children
Lung problems
The skin rash usually occurs at the same time as muscle weakness, but may precede
muscle weakness by a few weeks. Sometimes, the skin rash alone determines the
diagnosis. In some children with dermatomyositis, the skin may become thick and hard
in a way similar to scleroderma. When this happens, the condition is called
sclerodermatomyositis.
Weakness in muscles, such as your hips and shoulders, can lead to difficulty in getting
out of chairs, climbing stairs, brushing your hair or working with your arms over your
head. Weakness in your neck muscles can make it hard to hold your head up.
Causes
Your immune system
Dermatomyositis belongs to a group of conditions called inflammatory myopathies.
Myopathies are diseases or abnormal conditions of the muscles. The cause of most
inflammatory myopathies is unknown.
One of these diseases that's similar to dermatomyositis is polymyositis. Polymyositis
leads to many of the same symptoms as dermatomyositis, but does not cause skin
inflammation or a rash.
Some other inflammatory muscle diseases are: inclusion body myositis, which
progresses more slowly than other forms; myositis associated with other connective
tissue diseases, such as lupus or scleroderma; and myositis associated with cancer
(malignancy).
Immune system plays role
Doctors suspect that inflammatory myopathies are autoimmune disorders, in which
immune system attacks normal body components. Infections caused by bacteria,
parasites or viruses can cause inflammatory myopathies, but in most cases, doctors
aren't able to identify a preceding infection in dermatomyositis. Some doctors think
certain people may have a genetic susceptibility to the disease.
Typically, immune system works to protect your healthy cells from attacks by foreign
substances, such as bacteria and viruses. If you have dermatomyositis, an unknown
cause seems to trigger immune system to begin producing autoimmune antibodies (also
called autoantibodies) that attack your body's own tissues.
Small blood vessels in muscular tissue appear to be particularly affected. Inflammatory
cells surround the blood vessels and eventually lead to degeneration of muscle fibers.
Many people with dermatomyositis show a detectable level of autoantibodies in their
blood
Tests and diagnosis
Dermatomyositis is the most easily recognized of the inflammatory muscle diseases
because of its characteristic rash. Occasionally, a rash alone may prompt a diagnosis of
dermatomyositis without muscle involvement (amyopathic dermatomyositis).
In addition to a thorough evaluation, including examination of muscle strength and a
detailed family medical history, doctor may use some or all of the following tests to assist
in the diagnosis:

Electromyography. A doctor with specialized training inserts a thin needle
electrode through the skin into the muscle to be tested. Electrical activity is
measured as you relax or tighten the muscle. Changes in the pattern of electrical
activity can confirm a muscle disease. The doctor can determine the distribution of
the disease by testing different muscles.

Blood analysis. A blood test will let your doctor know if you have elevated
levels of muscle enzymes, such as creatine kinase (CK) and aldolase. Increased
CK and aldolase levels can indicate muscle damage.
A blood test can also determine whether autoantibodies are present in your blood.
In some cases, specific types of autoantibodies have been associated with certain
signs or symptoms of the disease, such as skin or lung involvement, and with how
the disease responds to treatment. Knowing whether you have these
autoantibodies may help your doctor determine the best treatment plan for you.

Muscle biopsy. A small piece of muscle tissue is removed surgically for
laboratory analysis. A muscle biopsy may reveal abnormalities in your muscles,
such as inflammation, damage or infection. The tissue sample can also be
examined for the presence of abnormal proteins and checked for enzyme
deficiencies.

Skin biopsy. A small piece of skin is removed for laboratory analysis. The skin
sample can confirm the diagnosis of dermatomyositis and rule out other disorders,
such as lupus. If the skin biopsy confirms the diagnosis, a muscle biopsy may not
be necessary.

Magnetic resonance imaging (MRI). A scanner creates cross-sectional
images of your muscles from data generated by a powerful magnetic field and
radio waves. These images can be viewed from any direction or plane. MRI scans
may help detect inflammation in your muscles.
Complications
You may experience these complications of dermatomyositis:

Difficulty swallowing. If the muscles in esophagus are affected, you may have
problems swallowing (dysphagia), which in turn may cause weight loss and
malnutrition.

Aspiration and pneumonia. Difficulty swallowing may also lead to entrance of
food or liquids, including saliva, into your lungs (aspiration), which can lead to
pneumonia.

Breathing problems. If your chest muscles are involved, you may experience
breathing problems, such as shortness of breath.

Gastrointestinal problems. Gastrointestinal ulceration and bleeding can occur.

Calcium deposits. Late in the disease, particularly if you've had the disease for
a long time, deposits of calcium can occur in your muscles, skin and connective
tissues (calcinosis).
Dermatomyositis may be associated with other conditions, including:

Raynaud's phenomenon. This is a condition in which your fingers, toes,
cheeks, nose and ears turn pale when exposed to cold temperatures.

Other connective tissue diseases. Diseases affecting tissues that hold your
body together, such as your muscles and joints, sometimes occur in conjunction
with each other. Conditions such as lupus, rheumatoid arthritis, scleroderma and
Sjogren's syndrome can occur in combination with dermatomyositis.

Cardiovascular disease. The muscle of your heart may become inflamed
(myocarditis). In a small number of people who have dermatomyositis, congestive
heart failure and heart arrhythmias may develop.

Lung disease. A condition called interstitial lung disease may occur with
dermatomyositis. Interstitial lung disease refers to a group of disorders that cause
scarring (fibrosis) of lung tissue, making lungs stiff and inelastic. Signs and
symptoms include a dry cough and shortness of breath.

Cancer. Dermatomyositis in adults has been linked to an increased likelihood of
cancer, particularly of the lungs, breasts, ovaries and gastrointestinal tract. Risk of
cancer increases with age, although it appears to level off three years after a
diagnosis of dermatomyositis.
Treatments and drugs
There's no cure for dermatomyositis, but treatment can improve your skin, muscle
strength and function. Treatment begun early in the disease process tends to be more
effective, often because there are fewer complications. Therapies include the following:

Corticosteroids. These medications suppress your immune system, limiting
the production of antibodies and reducing skin and muscle inflammation.
Corticosteroids, especially prednisone, are usually the first choice in treating
inflammatory myopathies, such as dermatomyositis.
Your doctor may start with a very high dose, and then decrease it as your signs
and symptoms improve. Improvement generally takes about two to four weeks.
Your doctor may also prescribe topical corticosteroids for your skin. Visible results
are usually evident within three to six months, but therapy is often needed for
years.
Prolonged use of corticosteroids can have serious side effects including
osteoporosis, weight gain, diabetes, increased risk of some infections, mood
swings, cataracts, high blood pressure, a redistribution of body fat and muscle
weakness. As a result, your doctor may recommend supplements, such as calcium
and vitamin D, and may prescribe bisphosphonates, such as alendronate
(Fosamax) or risedronate (Actonel).

Immunosuppressants. If your body doesn't respond adequately to
corticosteroids, your doctor may recommend other immunosuppressive drugs,
such as azathioprine (Imuran) or methotrexate (Rheumatrex). Your doctor may
prescribe these alone or in combination with corticosteroids.
When in combination, these additional immunosuppressants can be used to
lessen the dose and potential side effects of the corticosteroid.
Immunosuppressants such as cyclophosphamide (Cytoxan) and cyclosporine
(Neoral, Sandimmune) may improve signs and symptoms of dermatomyositis and
interstitial lung disease.

Antimalarial medications. For a persistent rash, your doctor may prescribe an
antimalarial medication, such as hydroxychloroquine (Plaquenil) or chloroquine
phosphate (Aralen).

Physical therapy. A physical therapist can show you exercises to maintain and
improve your strength and flexibility and advise an appropriate level of activity.
Your exercise program is likely to change during the course of the disease and
treatment period. Keeping active in general and pacing yourself will help
maintain muscle strength.

Surgery. Surgery may be an option to remove painful calcium deposits.

Pain relievers. Over-the-counter drugs such as aspirin, ibuprofen (Advil,
Motrin, others) and acetaminophen (Tylenol, others), can be used to treat any
accompanying pain. If these aren't sufficient, your doctor may prescribe a
stronger pain reliever, such as codeine.


Dermatomyositis treatments that are still under investigation include:
Plasmapheresis. This treatment, also called plasma exchange, is a type of
blood cleansing in which damaging antibodies are removed from your blood.

Radiation therapy. This involves irradiation of the lymph nodes to suppress
your immune system.

Intravenous immunoglobulin (IVIg
Fludarabine (Fludara). This agent prevents the development and growth of malignant
cells.
Tacrolimus (Prograf). This transplant-rejection drug may work to inhibit the immune
system.
Monoclonal antibodies. These man-made antibodies are designed to target and
destroy specific types of cells