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Alternative Names: When associated with skin rash, it is referred to as Dermatomyositis.
Polymyositis is an inflammatory disease of muscle, its cause unknown. It begins when white blood cells - the immune cells of inflammation - spontaneously invade muscles. The muscles affected are mostly those closest to the trunk or torso. This in turn results in weakness which can be severe. It is a chronic illness with periods of increased symptoms, called flares or relapses, and decreased symptoms, known as remissions.
Polymyositis can affect other areas of the body and is, therefore, a systemic illness. Occasionally it is associated with cancer, or with other diseases of the connective tissues (for example, systemic lupus erythematosus, scleroderma or rheumatoid arthritis).
Aside from diseases with which polymyositis can be associated, many other diseases and conditions can mimic polymyositis. These include nerve-muscle diseases (such as muscular dystrophies), drug toxins (such as alcohol, cocaine, steroids and lovistatin), metabolic disorders (where muscle cells are unable to process chemicals normally), hormone disorders (such as abnormal thyroid, calcium, and magnesium conditions), and infectious diseases (such as influenza virus, AIDS, streptococcus and Lyme bacteria, pork tapeworm and schistosomiasis).
Incidence; Causes & Development
Polymyositis is slightly more common in females. It affects all age groups, although its onset is most common in middle childhood and in the twenties. Polymyositis occurs throughout the world.
To date, no cause of polymyositis has been isolated by medical researchers. There are indicators of heredity (genetic) susceptibility that can be found in some patients. There is also indirect evidence of infection by a virus that has yet to be identified in a form of polymyositis that is particularly resistant to treatment, called inclusion body myositis. This form of polymyositis is diagnosed by a pathologist - a physician specialist who interprets the microscope findings of muscle tissue. The muscle tissue in this form of polymyositis displays clear areas within the muscle cells (called vacuoles) when viewed under a microscope.
Signs & Symptoms
Weakness of muscles is the most common symptom of polymyositis. The muscles involved usually are those that are closest to the trunk of the body. The onset can be gradual or rapid, resulting in varying degrees of loss of muscle power. The loss of strength can be noticed as difficulty getting up from chairs, climbing stairs or lifting above the shoulders. Trouble with swallowing and weakness lifting the head from the pillow can occur. Occasionally (in some 25% of patients), the muscles ache and are tender to the touch.
Patients can also feel fatigue, a general feeling of discomfort and have weight loss and/or low-grade fever. With skin involvement (dermatomyositis), the eyes can be surrounded by a violet discoloration with swelling. There can be scaly reddish discoloration over the knuckles, elbows and knees (Gottron's sign). There can also be reddish rash on the face, neck and upper chest. Hard lumps of calcium deposits can develop in the fatty layer of the skin, most commonly in childhood dermatomyositis.
Heart and lung involvement can lead to irregular heart rhythm and shortness of breath. Both polymyositis and dermatomyositis can sometimes be associated with cancers, including lymphoma, breast, lung, ovarian, and colon cancer. The cancer risk is reported to be much greater with dermatomyositis than polymyositis.
Diagnosis & Tests
When a patient first sees a doctor, recent symptoms - especially those concerning weakness - will be discussed. The condition of many other body areas might be reviewed, for example the skin, heart, lungs and joints. An examination will further focus on these and other systems. Various measures of strength might be noted.
Blood testing usually reveals abnormally high levels of muscle enzymes, CPK or creatinine phosphokinase and aldolase. These enzymes are released into the blood by muscle that is being damaged by inflammation. They can also be used as measures of the activity of the inflammation. Other routine blood and urine tests can also look for internal organ abnormalities. Chest X-rays, mammograms, PAP smears and other screening tests might be considered.
An electromyograph (EMG) and nerve conduction velocity are electrical tests of muscle and nerves that can show abnormal findings typical of polymyositis as well as exclude other nerve-muscle diseases.
A muscle biopsy is used to confirm the presence of muscle inflammation typical only of polymyositis. This is a surgical procedure whereby muscle tissue is removed for analysis by a pathologist. Muscles often used for biopsy include the quadreceps muscle of the front of the thigh, the biceps muscle of the arm and the deltoid muscle of the shoulder.
Prognosis
Patients can ultimately do well, especially with early medical treatment of disease and disease flares. The disease frequently becomes inactive, and rehabilitation of atrophied muscle becomes a long-term project. Inclusion Body Myositis is often more resistant to treatment than the usual form of disease.
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Signs, symptoms & indicators of Polymyositis:
Recommendations and treatments for Polymyositis: | | | | | Drug |  LDN - Low Dose Naltrexone
 Conventional Drug Use | Polymyositis is generally initially treated with high doses of corticosteroids - medications related to cortisone - given by orally or intravenously. They are very good at decreasing muscle inflammation but are usually are required for years. Their continued use will be based on what a doctor finds in terms of symptoms and muscle enzyme blood test results.
Corticosteroids have many predictable - and unpredictable - side-effects. In high doses they commonly cause an increase in appetite and weight, puffiness of the face and easy bruising. They can also cause sweats, facial hair growth, upset stomach, sensitive emotions, leg swelling, acne, cataracts, osteoporosis, high blood pressure, worsening of diabetes and increased risk of infection. A rare complication of cortisone medications is severe bone damage (avascular necrosis) which can destroy large joints, such as the hips and shoulders. In addition, abruptly stopping corticosteroids can cause flares of the disease and result in other side-effects including nausea, vomiting and decreased blood pressure.
Corticosteroids do not always help a lot and in such cases immunosuppressive medications are considered. These medicines can be effective by suppressing the immune response which attracts the white blood cells of inflammation to the muscles. Many types are now commonly used and others are still experimental. Methotrexate can be taken by mouth (Rheumatrex) or by injection into the body; Azathioprine (Imuran) is an oral drug. Both can cause liver and bone marrow side-effects and require regular blood monitoring. Cyclophosphamide (Cytoxan), chlorambucil (Leukeran) and cyclosporin (Sandimmune) have been used for serious complications of severe disease. These also can have severe side-effects which must be considered with each patient individually.
Patients with calcium deposits (calcinosis) from dermatomyositis can sometimes benefit by taking diltiazem (Cardizem) to shrink the size of the calcium deposits. This effect, however, occurs slowly - frequently over years. |
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Physical Medicine |
Manipulation| | Physical therapy is an important part of the treatment of polymyositis. When to begin, and the continued degree of exercise and range of motion of extremities is customized for different patients. |
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KEY | | Strong or generally accepted link | | | May do some good | | | Likely to help |
GLOSSARY
Acne
A chronic skin disorder due to inflammation of hair follicles and sebaceous glands (secretion glands in the skin).
AIDS
Acquired Immune Deficiency Syndrome. An immune system deficiency disorder that suddenly alters the body's ability to defend itself. The AIDS virus invades the T4 helper/inducer lymphocytes and multiplies, causing a breakdown in the body's immune system, eventually leading to overwhelming infection and/or cancer, with ultimate death.
Bacteria (Bacterial, Bacterium)
Microscopic germs. Some bacteria are "harmful" and can cause disease, while other "friendly" bacteria protect the body from harmful invading organisms.
Biopsy
Removal of a sample of tissue from a living being for diagnosis. A pathologist later uses a microscope to look for certain features, such as cancer cells, in the sample. A fine-needle aspiration biopsy involves inserting a thin needle to remove a small amount of tissue, sometimes using CT or ultrasound to guide the needle. A core biopsy involves obtaining a sample of tissue with a thick needle or by inserting a thin, lighted tube (laparoscope) into a small incision in the abdomen. Another biopsy method is to remove tissue during an operation.
Bruise (Bruised, Bruising)
Injury producing a hematoma or diffuse extravasation of blood without breaking the skin.
Calcium
The body's most abundant mineral. Its primary function is to help build and maintain bones and teeth. The body also needs calcium to carry nerve signals, keep the heart functioning, contract muscles, clot blood and maintain healthy skin. Calcium helps control blood acid-alkaline balance, plays a role in cell division, muscle growth and iron utilization, activates certain enzymes, and helps transport nutrients through cell membranes. Calcium also forms a cellular cement called ground substance that helps hold cells and tissues together.
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Cataract (Cataracts)
A steadily worsening disease of the eye in which the lens becomes cloudy as a result of the precipitation of proteins. Most cataracts are caused by the functions of the body breaking down. Eye trauma, such as from a puncture wound, may also result in cataracts.
Chronic (Chronicity)
Usually referring to chronic illness: Illness extending over a long period of time.
Colon (Colonic)
The part of the large intestine that extends to the rectum. The colon takes the contents of the small intestine, moving them to the rectum by contracting.
Corticosteroid (Corticosteroids)
Steroid hormone produced by the adrenal cortex.
Dermatomyositis
A diffuse connective tissue disease.
Diabetes Mellitus (Diabetes, Diabetic, Diabetics)
A disease with increased blood glucose levels due to lack or ineffectiveness of insulin. Diabetes is found in two forms; insulin-dependent diabetes (juvenile-onset) and non-insulin-dependent (adult-onset). Symptoms include increased thirst; increased urination; weight loss in spite of increased appetite; fatigue; nausea; vomiting; frequent infections including bladder, vaginal, and skin; blurred vision; impotence in men; bad breath; cessation of menses; diminished skin fullness. Other symptoms include bleeding gums; ear noise/buzzing; diarrhea; depression; confusion.
Enzymes (Enzyme)
Specific protein catalysts produced by the cells that are crucial in chemical reactions and in building up or synthesizing most compounds in the body. Each enzyme performs a specific function without itself being consumed. For example, the digestive enzyme amylase acts on carbohydrates in foods to break them down.
Hormones (Hormone)
Chemical substances secreted by a variety of body organs that are carried by the bloodstream and usually influence cells some distance from the source of production. Hormones signal certain enzymes to perform their functions and, in this way, regulate such body functions as blood sugar levels, insulin levels, the menstrual cycle, and growth. These can be prescription, over-the-counter, synthetic or natural agents. Examples include adrenal hormones such as corticosteroids and aldosterone; glucagon, growth hormone, insulin, testosterone, estrogens, progestins, progesterone, DHEA, melatonin, and thyroid hormones such as thyroxine and calcitonin.
Immune System (Immune Response, Immunity)
A complex that protects the body from disease organisms and other foreign bodies. The system includes the humoral immune response and the cell-mediated response. The immune system also protects the body from invasion by making local barriers and inflammation. The process may involve acquired immunity (the ability to learn and remember a specific infectious agent), or innate immunity (the genetically programmed system of responses that attack, digest, remove, and initiate inflammation and tissue healing).
Liver (Hepatic)
The largest and one of the most complex organs of the body, the liver is responsible for much of the metabolism of fats, proteins and carbohydrates. It is the site of much of the body's detoxification. It is connected very closely with digestion and the regulation of blood sugar, among many other functions. Found behind the ribs on the right side of the abdomen, it has many important functions such as removing harmful material from the blood, making enzymes and bile that help digest food, and converting food into substances needed for life and growth. Hepatic: Pertaining to the liver.
Lung (Lungs, Pulmonary)
Organ of the body, located in the chest cavity which is designed to bring oxygen from the air into the blood stream, while also expelling carbon dioxide and other waste gases out of the body. Pulmonary: Related to the lungs.
Lymphoma (Lymphomas)
Any tumor of the lymphatic tissues.
Magnesium
An essential mineral. The chief function of magnesium is to activate certain enzymes, especially those related to carbohydrate metabolism. Another role is to maintain the electrical potential across nerve and muscle membranes. It is essential for proper heartbeat and nerve transmission. Magnesium controls many cellular functions. It is involved in protein formation, DNA production and function and in the storage and release of energy in ATP. Magnesium is closely related to calcium and phosphorus in body function. The average adult body contains approximately one ounce of magnesium. It is the fifth mineral in abundance within the body--behind calcium, phosphorus, potassium and sodium. Although about 70 percent of the body's magnesium is contained in the teeth and bones, its most important functions are carried out by the remainder which is present in the cells of the soft tissues and in the fluid surrounding those cells.
Metabolism (Metabolic, Metabolize, Metabolizes, Metabolizing)
The chemical processes of living cells in which energy is produced in order to replace and repair tissues and maintain a healthy body. Responsible for the production of energy, biosynthesis of important substances, and degradation of various compounds. Also defined as the sum total of changes in an organism in order to achieve a balance (homeostasis): Catabolic burns up, anabolic stores and builds up; the sum of their work is metabolism.
Nausea
Symptoms resulting from an inclination to vomit.
Necrosis
Death of one or more cells, or of a portion of a tissue or organ.
Osteoporosis
A disease in which bone tissue becomes porous and brittle. The disease primarily affects postmenopausal women.
Pathology (Pathologist)
Disease, particularly one with clear and obvious changes in structure or function; the study of same.
Rheumatoid Arthritis
A long-term, destructive connective tissue disease that results from the body rejecting its own tissue cells (autoimmune reaction).
Scleroderma (Systemic Sclerosis)
An autoimmune disease of the connective tissue, characterized by the formation of scar tissue (fibrosis) in the skin and organs of the body. This leads to thickness and firmness of involved areas.
Steroid (Steroids)
Any of a large number of hormonal substances with a similar basic chemical structure containing a 17-carbon 14-ring system and including the sterols and various hormones and glycosides.
Stomach
A hollow, muscular, J-shaped pouch located in the upper part of the abdomen to the left of the midline. The upper end (fundus) is large and dome-shaped; the area just below the fundus is called the body of the stomach. The fundus and the body are often referred to as the cardiac portion of the stomach. The lower (pyloric) portion curves downward and to the right and includes the antrum and the pylorus. The function of the stomach is to begin digestion by physically breaking down food received from the esophagus. The tissues of the stomach wall are composed of three types of muscle fibers: circular, longitudinal and oblique. These fibers create structural elasticity and contractibility, both of which are needed for digestion. The stomach mucosa contains cells which secrete hydrochloric acid and this in turn activates the other gastric enzymes pepsin and rennin. To protect itself from being destroyed by its own enzymes, the stomach's mucous lining must constantly regenerate itself.
Streptococcus (Strep)
A genus of gram-staining chain-forming cocci bacteria. Some are responsible for common and potentially serious human infections, ranging from scarlet fever and strep throat to bacterial endocarditis and pus pockets. Most of the disease-potential streps are also a normal part of the skin, mouth and upper respiratory flora.
Thyroid (Thyroid Gland)
The thyroid gland is an organ with many veins, anchored around the front of the throat near the voice box. It is essential to normal body growth in infancy and childhood. It absorbs iodine from the diet and releases thyroid hormones - iodine-containing compounds that help govern the rate of the body's metabolism (its total life processes), affecting body temperature, and regulating protein, fat and carbohydrate catabolism in all cells. They keep up growth hormone release, skeletal maturation, and heart rate, force, and output. They promote central nervous system growth, stimulate the making of many enzymes, and are necessary for muscle tone and vigor. To a high degree, metabolism is regulated by the hormone thyroxine, which can be made by the thyroid if enough organic iodine is available. An enlarged thyroid gland that is not cancer is sometimes called goitre.
Virus (Viri, Viruses)
Any of a vast group of minute structures composed of a protein coat and a core of DNA and/or RNA that reproduces in the cells of the infected host. Capable of infecting all animals and plants, causing devastating disease in immunocompromised individuals. Viruses are not affected by antibiotics, and are completely dependent upon the cells of the infected host for the ability to reproduce.
White Blood Cell (WBC, White Blood Cells)
A blood cell that does not contain hemoglobin: a blood corpuscle responsible for maintaining the body's immune surveillance system against invasion by foreign substances such as viruses or bacteria. White cells become specifically programmed against foreign invaders and work to inactivate and rid the body of a foreign substance. White blood cells are composed primarily of neutrophils, monocytes and lymphocytes. Lymphocytes are either T-cells or B-cells. T-cells (CD3 cells) are divided into T-helper (CD4 cells) and T-suppressor/cytotoxic (CD8 cells) cells.
X-rays (X-ray)
High-energy radiation used to take pictures of areas inside the body.
Last updated: Jan 03, 2010
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