Inflammatory myopathy: Difference between revisions
(Created page with "<section begin="neurology" /><section begin="dermatology" />'''Inflammatory myopathy''', also called '''myositis,''' is a subtype of myopathy where there is inflammation of muscle. === Etiology === * Polymyositis (PM) * Dermatomyositis (DM) * Necrotising myositis * Inclusion body myositis (IBM) * Overlap myositis * Paraneoplastic myositis Dermatomyositis and necrotising myositis can either be primary (idiopathic) or secondary to adenocarcinoma. === Clinical featu...") |
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<section begin="neurology" /><section begin="dermatology" />'''Inflammatory myopathy''', also called '''myositis,''' is a subtype of [[myopathy]] where there is inflammation of muscle. | <section begin="neurology" /><section begin="dermatology" />'''Inflammatory myopathy''', also called '''myositis,''' is a subtype of [[myopathy]] where there is inflammation of muscle. | ||
== Etiology == | |||
* Polymyositis (PM) | * Polymyositis (PM) | ||
* Dermatomyositis (DM) | * Dermatomyositis (DM) | ||
| Line 12: | Line 11: | ||
Dermatomyositis and necrotising myositis can either be primary (idiopathic) or secondary to adenocarcinoma. | Dermatomyositis and necrotising myositis can either be primary (idiopathic) or secondary to adenocarcinoma. | ||
== Clinical features == | |||
In most types of myositis there is proximal weakness, atrophy, and muscle pain. The only exception is inclusion body myositis, in which there is distal muscle weakness. IBM affects elderly. | In most types of myositis there is proximal weakness, atrophy, and muscle pain. The only exception is inclusion body myositis, in which there is distal muscle weakness. IBM affects elderly. | ||
In dermatomyositis there are also skin symptoms, namely heliotrope rash and Gottron papules. Polymyositis is like dermatomyositis but without skin symptoms. Necrotising myositis is similar to them but worse. | In dermatomyositis there are also skin symptoms, namely heliotrope rash (erythematous/purple rash of periorbital area) and Gottron papules (erythematous papules on knuckles) and shawl erythema (erythema of neck and upper trunk). Polymyositis is like dermatomyositis but without skin symptoms. Necrotising myositis is similar to them but worse. | ||
== Diagnosis and evaluation == | |||
The creatine kinase (CK) is elevated in most cases. MRI can show the distribution and extent of inflammation and can guide the location for biopsy. | The creatine kinase (CK) is elevated in most cases. MRI can show the distribution and extent of inflammation and can guide the location for biopsy. | ||
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EMG can differentiate between neurogenic and myopathic problems. | EMG can differentiate between neurogenic and myopathic problems. | ||
In dermatomyositis and necrotising myositis it’s important to rule out adenocarcinoma. | In dermatomyositis and necrotising myositis it’s important to rule out adenocarcinoma.<section begin="dermatology" /> | ||
<section begin="dermatology" /> | |||
== Treatment == | |||
The treatment is usually immunosuppressants, usually steroids + azathioprine or methotrexate.<section end="dermatology" /> Immunosuppressants is not effective for IBM, however.<section end="neurology" /> | The treatment is usually immunosuppressants, usually steroids + azathioprine or methotrexate.<section end="dermatology" /> Immunosuppressants is not effective for IBM, however.<section end="neurology" /> | ||
[[Category:Rheumatology]] | [[Category:Rheumatology]] | ||
Latest revision as of 19:03, 17 July 2024
Inflammatory myopathy, also called myositis, is a subtype of myopathy where there is inflammation of muscle.
Etiology
- Polymyositis (PM)
- Dermatomyositis (DM)
- Necrotising myositis
- Inclusion body myositis (IBM)
- Overlap myositis
- Paraneoplastic myositis
Dermatomyositis and necrotising myositis can either be primary (idiopathic) or secondary to adenocarcinoma.
Clinical features
In most types of myositis there is proximal weakness, atrophy, and muscle pain. The only exception is inclusion body myositis, in which there is distal muscle weakness. IBM affects elderly.
In dermatomyositis there are also skin symptoms, namely heliotrope rash (erythematous/purple rash of periorbital area) and Gottron papules (erythematous papules on knuckles) and shawl erythema (erythema of neck and upper trunk). Polymyositis is like dermatomyositis but without skin symptoms. Necrotising myositis is similar to them but worse.
Diagnosis and evaluation
The creatine kinase (CK) is elevated in most cases. MRI can show the distribution and extent of inflammation and can guide the location for biopsy.
Muscle biopsy is usually required for diagnosis. On muscle biopsy, inflammation, and MHC-I expression (which is usually not expressed on muscle) can be seen. In necrotising myositis, necrosis can be seen, and in IBM, vacuoles are present.
EMG can differentiate between neurogenic and myopathic problems.
In dermatomyositis and necrotising myositis it’s important to rule out adenocarcinoma.
Treatment
The treatment is usually immunosuppressants, usually steroids + azathioprine or methotrexate. Immunosuppressants is not effective for IBM, however.