Dermatomyositis
Updates to Article Attributes
Body
was changed:
Dermatomyositis is an autoimmune inflammatory myositis.
Epidemiology
There is a recognised female predilection. It has a bimodal age of presentation depending on the variant:
- juvenile dermatomyositis (JDM): affects children and tends to be more severe
- adult dermatomyositis (ADM): typically affects adults around the age of 50
Clinical presentation
The classic presentation is proximal, symmetrical motor weakness with cutaneous changes. Dysphagia, myalgia, fevers, and loss of weight are other features 7.
Pathology
There is cell mediated injury targeted at striated muscle with resultant atrophy resultant atrophy, oedema, coagulation necrosis, fibrosis and calcification calcification.
Markers
- elevlated muscle enzymes (CK)
- elevated muscle specific antibodies
- anti RNA
- anti Mi2
Associations
-
interstitial lung disease 2: typically gives a patchy and subpleural
consolidationconsolidation withparenchymal bandsparenchymal bands - internal malignancy 1: can occur as part of a paraneoplastic syndrome (e.g. lung cancer)
Radiographic features
Plain film
- typically shows dystrophic calcification in muscles and soft tissues (calcinosis universalis)
- sheet-like although at least four patterns have described with childhood dermatomyositis 4
- classically seen affecting the thigh regions
- chest radiograph may show diaphragmatic elevation
- acroosteolysis
Fluoroscopy
Barium swallow
- may show disordered peristalsis involving the upper oesophagus: portion supplied by skeletal muscle
MRI
- T2: generally hyperintense signal throughout the affected muscles; calcific areas may be low signal; perimuscular oedema may additionally appear as high signal; signal intensity may return to normal after treatment 4
Differential diagnosis
General imaging differential considerations include:
- polymyositis: does not affect skin
-</ul><h4>Clinical presentation</h4><p>The classic presentation is proximal, symmetrical motor weakness with cutaneous changes. Dysphagia, myalgia, fevers, and loss of weight are other features <sup>7</sup>. </p><h4>Pathology</h4><p>There is cell mediated injury targeted at striated muscle with resultant atrophy, oedema, coagulation necrosis, fibrosis and calcification.</p><h5>Markers</h5><ul>- +</ul><h4>Clinical presentation</h4><p>The classic presentation is proximal, symmetrical motor weakness with cutaneous changes. Dysphagia, myalgia, fevers, and loss of weight are other features <sup>7</sup>.</p><h4>Pathology</h4><p>There is cell mediated injury targeted at striated muscle with resultant atrophy, oedema, coagulation necrosis, fibrosis and calcification.</p><h5>Markers</h5><ul>
-<li>elevated muscle specific antibodies <ul>- +<li>elevated muscle specific antibodies<ul>
-<a href="/articles/interstitial-lung-disease">interstitial lung disease</a> <sup>2</sup>: typically gives a patchy and subpleural consolidation with parenchymal bands</li>- +<a href="/articles/interstitial-lung-disease">interstitial lung disease</a> <sup>2</sup>: typically gives a patchy and subpleural consolidation with parenchymal bands</li>
-</ul><h4>Radiographic features</h4><h5>Plain film </h5><ul>- +</ul><h4>Radiographic features</h4><h5>Plain film</h5><ul>
-</ul><h5>Fluoroscopy</h5><h6>Barium swallow</h6><ul><li>may show disordered peristalsis involving the upper oesophagus: portion supplied by skeletal muscle</li></ul><h5>MRI </h5><ul><li>- +</ul><h5>Fluoroscopy</h5><h6>Barium swallow</h6><ul><li>may show disordered peristalsis involving the upper oesophagus: portion supplied by skeletal muscle</li></ul><h5>MRI</h5><ul><li>
Images Changes:
Image 9 CT (lung window) ( create )
Image 10 MRI (STIR) ( create )
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