Dermatomyositis
Encyclopedia
Dermatomyositis is a connective-tissue disease related to polymyositis
(PM) and Bramaticosis that is characterized by inflammation
of the muscles and the skin.
and Epstein-Barr virus
. Some cases of dermatomyositis actually "overlap" (are combined with) other autoimmune diseases such as: Sjögren's syndrome
, lupus
, scleroderma
, or vasculitis
. Because of the link between dermatomyositis and autoimmune disease, doctors and patients suspecting dermatomyositis may find it helpful to run an ANA
- antinuclear antibody - test, which in cases of a lupus
-like nature may be positive (usually from 1:160 to 1:640, with normal ranges at 1:40 and below).
Several cases of polymyositis
and dermatomyositis were reported as being triggered by the use of various statin
drugs used to control blood cholesterol
. Muscle biopsies of these patients showed rhabdomyolysis
, and degeneration and regeneration of muscle tissue.
High blood levels of creatine kinase
(CPK) showed greater than 5 times the normal levels also supporting the rhabdomyolysis
findings. CPK is an enzyme found mainly in the heart, brain, and skeletal muscle that tends to rise when inflammation occurs during normal exercising. When these levels rise in excess of the normal level (less than 200), and become more than five times higher, severe cell damage to the muscles, brain, and heart ensue. The higher the CPK, the greater the cellular damage done. Extremely high levels of CPK cause rhabdomyolysis
to these muscles and organs. Without treatment, kidney
damage occurs and death in the more severe cases. Confirmed polymyositis
with the skin signs is known as dermatomyositis which amplifies the problem to various cancers.
Some cases of dermatomyositis are a paraneoplastic phenomenon, indicating the presence of cancer
. In cases involving cancer, the cancer is usually pre-existent, with removal of the cancer resulting in remission of the dermatomyositis. The onset of a rash in patients with pre-existing myositis
requires investigation of the neoplastic possibility.
In his 1988 article, Clinical pathologic correlations of Lyme disease by stage, noted Lyme disease
researcher Dr. Alan Steere observed, "[...] the perivascular lymphoid
infiltrate in clinical myositis
does not differ from that seen in polymyositis
or dermatomyositis. All of these histologic derangements suggest immunologic damage in response to persistence of the spirochete, however few in number."
, Intravenous immunoglobulin
, plasmapheresis
, chemotherapies, and other drugs, prognosis was poor. Now there are numerous treatments and immune-modulating drugs. Fortunately, over 90% of patients today will do well for many years, with remission being a possibility. However, it is still important that treatment begin as soon as possible.
findings sometimes include dystrophic calcification
s in the muscles, and patients may or may not notice small calcium deposits under the skin. Many do not have any calcium deposits of any kind. The rash also may come and go, and may not be dependent on the severity of the muscle involvement at the time. "Gottron's papules", pink patches on the knuckles and other extensor surfaces, and priapism, are associated with this disorder.
Another concern is interstitial lung disease.
Based on the conclusion of the paper "Interstitial lung disease (ILD) in polymyositis and dermatomyositis" by Maryann Fathi and Ingrid E Lundberg published 12/13/2005:
Investigations to detect interstitial lung disease should be performed during the initial evaluation as well as during follow-up of patients with myositis, because ILD is a frequent manifestation in patients with polymyositis or dermatomyositis and because ILD is associated with increased morbidity and mortality. This evaluation should include chest radiograph, HRCT of lungs, pulmonary function tests including diffusing capacity, and serum levels of anti-Jo1 antibodies. In the patients with ILD, clinical or subclinical, treatment with high doses of corticosteroids in combination with other immunosuppressive therapy should be initiated. Some histopathologic features including DAD, UIP, neutrophil alveolitis, digital infarcts showing microangiopathy in dermatomyositis, and amyopathic dermatomyositis have all been reported as risk factors for poor outcome. Presence of these factors suggests the use of aggressive immunosuppressive therapy (i.e. Methotrexate) and careful monitoring of lung function.
. It is related to polymyositis
and inclusion body myositis
.
There is a form of this disorder that strikes children, known as juvenile dermatomyositis
(JDM). For the most part Juvenile dermatomyositis is the same as the adult form, but the relationship with cancer is far lower, or non-existent.
and symmetric proximal muscle weakness
which may be accompanied by pain. The pain may resemble the type experienced after strenuous exercise. Some dermatomyositis patients have little pain, while in others (esp. in JDM), the pain may be severe. It is important to remember that this condition varies from person to person in many ways. Also in many cases muscle may deteriorate and render the patient temporarily paralyzed unable to walk, run, get out of bed, or even swallow food and liquids.
Skin findings occur in dermatomyositis but not PM and are generally present at diagnosis. Gottron's sign is an erythematous, scaly eruption occurring in symmetric fashion over the MCP
and interphalangeal joints (can mimic psoriasis
). The heliotrope
or "lilac" rash is a violaceous eruption on the upper eyelids and in rare cases on the lower eyelids as well, often with itching and swelling (most specific, though uncommon). Shawl (or V-) sign is a diffuse, flat, erythematous lesion
over the back and shoulders or in a "V" over the posterior neck and back or neck and upper chest, which worsens with UV light. Erythroderma
is not a flat, erythematous lesion
similar to the shawl sign but located in other areas, such as the malar
region and the forehead. Periungual telangiectasias and erythema
occur.
Mechanic's hands (also in PM) refers to rough, cracked skin at the tips and lateral aspects of the fingers forming irregular dirty-appearing lines that resemble those seen in a laborer (this is also associated with the anti-synthetase syndrome
). See: sclerodactyly
. Psoriaform changes in the scalp can occur. Centripetal flagellate
erythema
comprises linear
, violaceous streaks on the trunk (possibly caused by itching pruritic skin). Calcinosis cutis
(deposition of calcium
in the skin) is usually seen in juvenile dermatomyositis, not adult dermatomyositis. Dysphagia
(difficulty swallowing) is another feature, occurring in as many as 33% of cases.
, EMG
,and blood tests. It should be noted, however, that only muscle biopsy is truly diagnostic (pathognomonic
); liver enzymes and EMG are relatively non-specific. Liver enzymes, specifically creatine phosphokinase (CPK), are the major tool in assessing the progress of the disease and/or the efficacy of treatment. On the muscle biopsy, there are two classic microscopic
findings of dermatomyositis. They are:
Dermatomyositis is associated with autoantibodies
, especially anti-Jo1 antibody.
Aggregates of mature lymphocytes with small, dark nuclei and scant cytoplasm are seen surrounding vessels. Other inflammatory cells are distinctly uncommon. Immunohistochemistry
can be used to demonstrate that both B- and T-cells are present in approximately equal numbers.
-mediated damage of microscopic vessels with muscle atrophy and lymphocytic inflammation secondary to tissue ischemia
.
predominant inflammatory myopathies. If present, the characteristic perifascicular atrophy makes this distinction trivial.
There is some overlap in the microscopic appearances of different inflammatory myopathies, but some helpful differences are often present. The rimmed vacuoles of inclusion body myositis
(IBM) are absent in dermatomyositis. Polymyositis is characterised by diffuse or patchy inflammation of the muscle fascicles, a random pattern of muscle atrophy, and T-cell predominance with T-cells seen invading otherwise viable appearing muscle fibers. Pubmed
reports 15 articles where Dermatomyositis and Lyme Disease are associated.
may supplement treatment to enhance quality of life.
Medications to help relieve symptoms include:
Polymyositis
Polymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
(PM) and Bramaticosis that is characterized by inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
of the muscles and the skin.
Causes
The cause is unknown, but it may result from either a viral infection or an autoimmune reaction. In the latter case it is a systemic autoimmune disease. Many people diagnosed with dermatomyositis were previously diagnosed with infectious mononucleosisInfectious mononucleosis
Infectious mononucleosis is an infectious, widespread viral...
and Epstein-Barr virus
Epstein-Barr virus
The Epstein–Barr virus , also called human herpesvirus 4 , is a virus of the herpes family and is one of the most common viruses in humans. It is best known as the cause of infectious mononucleosis...
. Some cases of dermatomyositis actually "overlap" (are combined with) other autoimmune diseases such as: Sjögren's syndrome
Sjögren's syndrome
Sjögren's syndrome , also known as "Mikulicz disease" and "Sicca syndrome", is a systemic autoimmune disease in which immune cells attack and destroy the exocrine glands that produce tears and saliva....
, lupus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
, scleroderma
Scleroderma
Systemic sclerosis or systemic scleroderma is a systemic autoimmune disease or systemic connective tissue disease that is a subtype of scleroderma.-Skin symptoms:...
, or vasculitis
Vasculitis
Vasculitis refers to a heterogeneous group of disorders that are characterized by inflammatory destruction of blood vessels. Both arteries and veins are affected. Lymphangitis is sometimes considered a type of vasculitis...
. Because of the link between dermatomyositis and autoimmune disease, doctors and patients suspecting dermatomyositis may find it helpful to run an ANA
Anti-nuclear antibody
Anti-nuclear antibodies are autoantibodies directed against contents of the cell nucleus....
- antinuclear antibody - test, which in cases of a lupus
Lupus erythematosus
Lupus erythematosus is a category for a collection of diseases with similar underlying problems with immunity . Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs...
-like nature may be positive (usually from 1:160 to 1:640, with normal ranges at 1:40 and below).
Several cases of polymyositis
Polymyositis
Polymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
and dermatomyositis were reported as being triggered by the use of various statin
Statin
Statins are a class of drugs used to lower cholesterol levels by inhibiting the enzyme HMG-CoA reductase, which plays a central role in the production of cholesterol in the liver. Increased cholesterol levels have been associated with cardiovascular diseases, and statins are therefore used in the...
drugs used to control blood cholesterol
Cholesterol
Cholesterol is a complex isoprenoid. Specifically, it is a waxy steroid of fat that is produced in the liver or intestines. It is used to produce hormones and cell membranes and is transported in the blood plasma of all mammals. It is an essential structural component of mammalian cell membranes...
. Muscle biopsies of these patients showed rhabdomyolysis
Rhabdomyolysis
Rhabdomyolysis is a condition in which damaged skeletal muscle tissue breaks down rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure...
, and degeneration and regeneration of muscle tissue.
High blood levels of creatine kinase
Creatine kinase
Creatine kinase , also known as creatine phosphokinase or phospho-creatine kinase , is an enzyme expressed by various tissues and cell types. CK catalyses the conversion of creatine and consumes adenosine triphosphate to create phosphocreatine and adenosine diphosphate...
(CPK) showed greater than 5 times the normal levels also supporting the rhabdomyolysis
Rhabdomyolysis
Rhabdomyolysis is a condition in which damaged skeletal muscle tissue breaks down rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure...
findings. CPK is an enzyme found mainly in the heart, brain, and skeletal muscle that tends to rise when inflammation occurs during normal exercising. When these levels rise in excess of the normal level (less than 200), and become more than five times higher, severe cell damage to the muscles, brain, and heart ensue. The higher the CPK, the greater the cellular damage done. Extremely high levels of CPK cause rhabdomyolysis
Rhabdomyolysis
Rhabdomyolysis is a condition in which damaged skeletal muscle tissue breaks down rapidly. Breakdown products of damaged muscle cells are released into the bloodstream; some of these, such as the protein myoglobin, are harmful to the kidneys and may lead to kidney failure...
to these muscles and organs. Without treatment, kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
damage occurs and death in the more severe cases. Confirmed polymyositis
Polymyositis
Polymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
with the skin signs is known as dermatomyositis which amplifies the problem to various cancers.
Some cases of dermatomyositis are a paraneoplastic phenomenon, indicating the presence of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
. In cases involving cancer, the cancer is usually pre-existent, with removal of the cancer resulting in remission of the dermatomyositis. The onset of a rash in patients with pre-existing myositis
Myositis
Myositis is a general term for inflammation of the muscles. Many such conditions are considered likely to be caused by autoimmune conditions, rather than directly due to infection It is also a documented side effect of the lipid-lowering drugs statins and fibrates.Elevation of creatine kinase in...
requires investigation of the neoplastic possibility.
In his 1988 article, Clinical pathologic correlations of Lyme disease by stage, noted Lyme disease
Lyme disease
Lyme disease, or Lyme borreliosis, is an emerging infectious disease caused by at least three species of bacteria belonging to the genus Borrelia. Borrelia burgdorferi sensu stricto is the main cause of Lyme disease in the United States, whereas Borrelia afzelii and Borrelia garinii cause most...
researcher Dr. Alan Steere observed, "[...] the perivascular lymphoid
Lymphoid
Lymphoid is a term used to describe lymph or the lymphatic system.In the context of lymphoid leukemia, it refers specifically to lymphocytes Lymphoid leukemias and lymphomas are now considered to be tumors of the same type of cell lineage. They are called "leukemia" when in the blood or marrow and...
infiltrate in clinical myositis
Myositis
Myositis is a general term for inflammation of the muscles. Many such conditions are considered likely to be caused by autoimmune conditions, rather than directly due to infection It is also a documented side effect of the lipid-lowering drugs statins and fibrates.Elevation of creatine kinase in...
does not differ from that seen in polymyositis
Polymyositis
Polymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
or dermatomyositis. All of these histologic derangements suggest immunologic damage in response to persistence of the spirochete, however few in number."
Prognosis
Before the advent of modern treatments such as prednisonePrednisone
Prednisone is a synthetic corticosteroid drug that is particularly effective as an immunosuppressant drug. It is used to treat certain inflammatory diseases and some types of cancer, but has significant adverse effects...
, Intravenous immunoglobulin
Intravenous immunoglobulin
Intravenous immunoglobulin is a blood product administered intravenously. It contains the pooled IgG extracted from the plasma of over one thousand blood donors. IVIG's effects last between 2 weeks and 3 months...
, plasmapheresis
Plasmapheresis
Plasmapheresis is the removal, treatment, and return of blood plasma from blood circulation. It is thus an extracorporeal therapy...
, chemotherapies, and other drugs, prognosis was poor. Now there are numerous treatments and immune-modulating drugs. Fortunately, over 90% of patients today will do well for many years, with remission being a possibility. However, it is still important that treatment begin as soon as possible.
Presentation
X-rayX-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
findings sometimes include dystrophic calcification
Calcification
Calcification is the process in which calcium salts build up in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification.-Causes:...
s in the muscles, and patients may or may not notice small calcium deposits under the skin. Many do not have any calcium deposits of any kind. The rash also may come and go, and may not be dependent on the severity of the muscle involvement at the time. "Gottron's papules", pink patches on the knuckles and other extensor surfaces, and priapism, are associated with this disorder.
Another concern is interstitial lung disease.
Based on the conclusion of the paper "Interstitial lung disease (ILD) in polymyositis and dermatomyositis" by Maryann Fathi and Ingrid E Lundberg published 12/13/2005:
Investigations to detect interstitial lung disease should be performed during the initial evaluation as well as during follow-up of patients with myositis, because ILD is a frequent manifestation in patients with polymyositis or dermatomyositis and because ILD is associated with increased morbidity and mortality. This evaluation should include chest radiograph, HRCT of lungs, pulmonary function tests including diffusing capacity, and serum levels of anti-Jo1 antibodies. In the patients with ILD, clinical or subclinical, treatment with high doses of corticosteroids in combination with other immunosuppressive therapy should be initiated. Some histopathologic features including DAD, UIP, neutrophil alveolitis, digital infarcts showing microangiopathy in dermatomyositis, and amyopathic dermatomyositis have all been reported as risk factors for poor outcome. Presence of these factors suggests the use of aggressive immunosuppressive therapy (i.e. Methotrexate) and careful monitoring of lung function.
Classification
Dermatomyositis is a type of autoimmune connective tissue diseaseConnective tissue disease
A connective tissue disease is any disease that has the connective tissues of the body as a target of pathology. Connective tissue is any type of biological tissue with an extensive extracellular matrix that supports, binds together, and protects organs...
. It is related to polymyositis
Polymyositis
Polymyositis is a type of chronic inflammation of the muscles related to dermatomyositis and inclusion body myositis.-Signs and symptoms:...
and inclusion body myositis
Inclusion body myositis
Inclusion body myositis is an inflammatory muscle disease, characterized by slowly progressive weakness and wasting of both distal and proximal muscles, most apparent in the muscles of the arms and legs...
.
There is a form of this disorder that strikes children, known as juvenile dermatomyositis
Juvenile dermatomyositis
Juvenile dermatomyositis is an autoimmune disease causing vasculitis that manifests itself in children; it is the pediatric counterpart of dermatomyositis. In JDMS, the body's immune system attacks blood vessels throughout the body, causing inflammation called vasculitis...
(JDM). For the most part Juvenile dermatomyositis is the same as the adult form, but the relationship with cancer is far lower, or non-existent.
Signs and symptoms
The main symptoms include skin rashRash
A rash is a change of the skin which affects its color, appearance or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, cracked or blistered, swell and may be painful. The causes, and...
and symmetric proximal muscle weakness
Muscle weakness
Muscle weakness or myasthenia is a lack of muscle strength. The causes are many and can be divided into conditions that have true or perceived muscle weakness...
which may be accompanied by pain. The pain may resemble the type experienced after strenuous exercise. Some dermatomyositis patients have little pain, while in others (esp. in JDM), the pain may be severe. It is important to remember that this condition varies from person to person in many ways. Also in many cases muscle may deteriorate and render the patient temporarily paralyzed unable to walk, run, get out of bed, or even swallow food and liquids.
Skin findings occur in dermatomyositis but not PM and are generally present at diagnosis. Gottron's sign is an erythematous, scaly eruption occurring in symmetric fashion over the MCP
Metacarpophalangeal joint
The metacarpophalangeal joints are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cavities on the proximal ends of the first phalanges, with the exception of that of the thumb, which presents more of the characters of a ginglymoid joint...
and interphalangeal joints (can mimic psoriasis
Psoriasis
Psoriasis is an autoimmune disease that appears on the skin. It occurs when the immune system mistakes the skin cells as a pathogen, and sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. However, psoriasis has been linked to an increased risk of...
). The heliotrope
Heliotrope (color)
Heliotrope is a pink-purple tint that is a representation of the color of the heliotrope flower.The first recorded use of Heliotrope as a color name in English was in 1882.-Heliotrope in culture:Film...
or "lilac" rash is a violaceous eruption on the upper eyelids and in rare cases on the lower eyelids as well, often with itching and swelling (most specific, though uncommon). Shawl (or V-) sign is a diffuse, flat, erythematous lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
over the back and shoulders or in a "V" over the posterior neck and back or neck and upper chest, which worsens with UV light. Erythroderma
Erythroderma
Erythroderma is an inflammatory skin disease with erythema and scaling that affects nearly the entire cutaneous surface....
is not a flat, erythematous lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
similar to the shawl sign but located in other areas, such as the malar
Cheek
Cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. They may also be referred to as jowls. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve...
region and the forehead. Periungual telangiectasias and erythema
Erythema
Erythema is redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection, or inflammation...
occur.
Mechanic's hands (also in PM) refers to rough, cracked skin at the tips and lateral aspects of the fingers forming irregular dirty-appearing lines that resemble those seen in a laborer (this is also associated with the anti-synthetase syndrome
Syndrome
In medicine and psychology, a syndrome is the association of several clinically recognizable features, signs , symptoms , phenomena or characteristics that often occur together, so that the presence of one or more features alerts the physician to the possible presence of the others...
). See: sclerodactyly
Sclerodactyly
Sclerodactyly is a localized thickening and tightness of the skin of the fingers or toes. Sclerodactyly is commonly accompanied by atrophy of the underlying soft tissues....
. Psoriaform changes in the scalp can occur. Centripetal flagellate
Flagellate
Flagellates are organisms with one or more whip-like organelles called flagella. Some cells in animals may be flagellate, for instance the spermatozoa of most phyla. Flowering plants do not produce flagellate cells, but ferns, mosses, green algae, some gymnosperms and other closely related plants...
erythema
Erythema
Erythema is redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection, or inflammation...
comprises linear
Linear
In mathematics, a linear map or function f is a function which satisfies the following two properties:* Additivity : f = f + f...
, violaceous streaks on the trunk (possibly caused by itching pruritic skin). Calcinosis cutis
Calcinosis cutis
Calcinosis cutis is a type of calcinosis wherein calcium deposits form in the skin. A variety of factors can result in this condition. The most common source is dystrophic calcification, which occurs in soft tissue as a response to injury...
(deposition of calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
in the skin) is usually seen in juvenile dermatomyositis, not adult dermatomyositis. Dysphagia
Dysphagia
Dysphagia is the medical term for the symptom of difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, the term is sometimes used as a condition in its own right. Sufferers are sometimes unaware of their dysphagia....
(difficulty swallowing) is another feature, occurring in as many as 33% of cases.
Pathology
The diagnosis of dermatomyositis can be confirmed by muscle biopsyMuscle biopsy
In medicine, a muscle biopsy is a procedure in which a piece of muscle tissue is removed from an organism and examined microscopically. A biopsy needle is usually inserted into a muscle, wherein a small amount of tissue remains. Alternatively, an "open biopsy" can be performed by obtaining the...
, EMG
Electromyography
Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...
,and blood tests. It should be noted, however, that only muscle biopsy is truly diagnostic (pathognomonic
Pathognomonic
Pathognomonic is a term, often used in medicine, that means characteristic for a particular disease. A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doubt...
); liver enzymes and EMG are relatively non-specific. Liver enzymes, specifically creatine phosphokinase (CPK), are the major tool in assessing the progress of the disease and/or the efficacy of treatment. On the muscle biopsy, there are two classic microscopic
Microscopic
The microscopic scale is the scale of size or length used to describe objects smaller than those that can easily be seen by the naked eye and which require a lens or microscope to see them clearly.-History:...
findings of dermatomyositis. They are:
- A mixed B- and T-cell perivascular inflammatory infiltrate
- Perifascicular muscle fiber atrophyAtrophyAtrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...
Dermatomyositis is associated with autoantibodies
Autoantibody
An autoantibody is an antibody manufactured by the immune system that is directed against one or more of the individual's own proteins. It is derived from the Greek "auto" which means "self", "anti" which means "against" and "body"...
, especially anti-Jo1 antibody.
Microscopic findings
Cross sections of muscle reveal muscle fascicles with small, shrunken polygonal muscle fibers on the periphery of a fascicle surrounding central muscle fibers of normal, uniform size.Aggregates of mature lymphocytes with small, dark nuclei and scant cytoplasm are seen surrounding vessels. Other inflammatory cells are distinctly uncommon. Immunohistochemistry
Immunohistochemistry
Immunohistochemistry or IHC refers to the process of detecting antigens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno," in reference to antibodies used in the procedure, and...
can be used to demonstrate that both B- and T-cells are present in approximately equal numbers.
Mechanism
The mechanism is conjectured to be complementComplement system
The complement system helps or “complements” the ability of antibodies and phagocytic cells to clear pathogens from an organism. It is part of the immune system called the innate immune system that is not adaptable and does not change over the course of an individual's lifetime...
-mediated damage of microscopic vessels with muscle atrophy and lymphocytic inflammation secondary to tissue ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
.
Differential diagnosis
Dermatomyositis must be differentiated from other common, lymphocyteLymphocyte
A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...
predominant inflammatory myopathies. If present, the characteristic perifascicular atrophy makes this distinction trivial.
There is some overlap in the microscopic appearances of different inflammatory myopathies, but some helpful differences are often present. The rimmed vacuoles of inclusion body myositis
Inclusion body myositis
Inclusion body myositis is an inflammatory muscle disease, characterized by slowly progressive weakness and wasting of both distal and proximal muscles, most apparent in the muscles of the arms and legs...
(IBM) are absent in dermatomyositis. Polymyositis is characterised by diffuse or patchy inflammation of the muscle fascicles, a random pattern of muscle atrophy, and T-cell predominance with T-cells seen invading otherwise viable appearing muscle fibers. Pubmed
PubMed
PubMed is a free database accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez information retrieval system...
reports 15 articles where Dermatomyositis and Lyme Disease are associated.
Treatment
This disease has no known cure. Specialized exercise therapyExercise therapy for idiopathic inflammatory myopathies
Although they vary in particulars, polymyositis, dermatomyositis and inclusion body myositis are idiopathic inflammatory myopathies primarily characterized by chronic inflammation of human skeletal muscle tissue that ultimately causes the necrosis of muscle cells. This degeneration leads to...
may supplement treatment to enhance quality of life.
Medications to help relieve symptoms include:
- PrednisolonePrednisolonePrednisolone is the active metabolite of prednisone, which is also used as a drug.-Uses:Prednisolone is a corticosteroid drug with predominant glucocorticoid and low mineralocorticoid activity, making it useful for the treatment of a wide range of inflammatory and auto-immune conditions such as...
- MethotrexateMethotrexateMethotrexate , abbreviated MTX and formerly known as amethopterin, is an antimetabolite and antifolate drug. It is used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions. It acts by inhibiting the metabolism of folic acid. Methotrexate...
- Mycophenolate (CellCept / Myfortic)
- Intravenous immunoglobulinIntravenous immunoglobulinIntravenous immunoglobulin is a blood product administered intravenously. It contains the pooled IgG extracted from the plasma of over one thousand blood donors. IVIG's effects last between 2 weeks and 3 months...
- AzathioprineAzathioprineAzathioprine is a purine analogue immunosuppressive drug. It is used to prevent organ rejection following organ transplantation and to treat a vast array of autoimmune diseases, including rheumatoid arthritis, pemphigus, inflammatory bowel disease , multiple sclerosis, autoimmune hepatitis, atopic...
- CyclophosphamideCyclophosphamideCyclophosphamide , also known as cytophosphane, is a nitrogen mustard alkylating agent, from the oxazophorines group....
- RituximabRituximabRituximab, sold under the trade names Rituxan and MabThera, is a chimeric monoclonal antibody against the protein CD20, which is primarily found on the surface of B cells...
Notable individuals with dermatomyositis
- Actor Laurence OlivierLaurence OlivierLaurence Kerr Olivier, Baron Olivier, OM was an English actor, director, and producer. He was one of the most famous and revered actors of the 20th century. He married three times, to fellow actors Jill Esmond, Vivien Leigh, and Joan Plowright...
(1907–1989) suffered from dermatomyositis in 1974 aged 67, and nearly died from the disease. - American footballAmerican footballAmerican football is a sport played between two teams of eleven with the objective of scoring points by advancing the ball into the opposing team's end zone. Known in the United States simply as football, it may also be referred to informally as gridiron football. The ball can be advanced by...
running backRunning backA running back is a gridiron football position, who is typically lined up in the offensive backfield. The primary roles of a running back are to receive handoffs from the quarterback for a rushing play, to catch passes from out of the backfield, and to block.There are usually one or two running...
Ricky BellRicky Bell (running back)Ricky Lynn Bell younger brother of recording artist Archie Bell, was an American professional football player who played running back in the NFL for the Tampa Bay Buccaneers and San Diego Chargers from 1977 to 1982...
, the 1976 Heisman TrophyHeisman TrophyThe Heisman Memorial Trophy Award , is awarded annually to the player deemed the most outstanding player in collegiate football. It was created in 1935 as the Downtown Athletic Club trophy and renamed in 1936 following the death of the Club's athletic director, John Heisman The Heisman Memorial...
runner up and #1 pick in the 1977 NFLNational Football LeagueThe National Football League is the highest level of professional American football in the United States, and is considered the top professional American football league in the world. It was formed by eleven teams in 1920 as the American Professional Football Association, with the league changing...
draft, died at age 29 from the disease. - Rob BuckmanRob BuckmanRobert Alexander Amiel "Rob" Buckman was a British-Canadian doctor of medicine, comedian and author, and president of the Humanist Association of Canada...
doctor, comedian, author and president of the Humanist Association of Canada.
External links
- The Myositis Association http://www.myositis.org
- Muscular Dystrophy Association http://www.mda.org/publications/fa-myosi.html
- The American College of Rheumatology's patient education page on myopathy
- Illustration of Gottron's papules at University of IowaUniversity of IowaThe University of Iowa is a public state-supported research university located in Iowa City, Iowa, United States. It is the oldest public university in the state. The university is organized into eleven colleges granting undergraduate, graduate, and professional degrees...
- The Johns Hopkins Myositis Center http://www.hopkinsmedicine.org/myositis/
- Myositis Support Group