Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 13-year-old girl was referred to our clinic because of a positive rheumatoid factor test, muscle pain and weakness. Laboratory evaluation revealed an increased ESR, hypergammaglobulinaemia, antinuclear antibodies, circulating immune complexes, complement consumption and elevated serum creatine kinase (CK) activity. A needle biopsy of the dolent muscle showed normal routine histology. Immunohistochemistry disclosed single lymphocytes and a weak myocytic HLA class I expression. The diagnosis of myositis was considered and corticosteroids were initiated, leading to an increase of complement levels and a decrease of CK-activity and ESR. She subjectively felt stronger but still reported exercise intolerance and metabolic myopathy was considered. Myophosphorylase activity was completely lacking, establishing the diagnosis of McArdle's disease. CK level was found to be elevated in an obese 4-year-old brother too, who refused extensive walking but reported no muscle pain. Myophosphorylase deficiency was demonstrated by histochemistry and by biochemical analysis of his muscle. The female case illustrates that in children with the clinical picture of inflammatory myopathy and serological but not clinical response to therapy underlying metabolic muscle disorders should be excluded. Since the pathogenesis of polymyositis remains unclear, we speculate that inflammatory changes observed in the muscles may have been initiated by muscular damage resulting from the underlying metabolic disease. The serological changes remained unexplained and may contribute to a so far undeterminable connective tissue disease.
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PMID:Glycogenosis type V (McArdle's disease) mimicking atypical myositis. 1125 43

We describe the case of a 69-year-old man with a history of muscular symptoms dating back to his childhood; McArdle's disease (glycogen-storage disease V) was diagnosed following an episode of myositis in which a statin and physical exertion appear to have been precipitating factors. This case demonstrates that the ischaemic lactate-ammonia test still has a place in screening patients with symptoms suggestive of McArdle's disease and emphasizes the importance of carrying out glycogen phosphorylase histochemistry on the skeletal muscle biopsy to confirm the diagnosis. In patients who develop a raised plasma creatine kinase level or muscular symptoms during lipid-lowering therapy, the clinician should be alert to the possibility of an underlying myopathy.
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PMID:McArdle's disease diagnosed following statin-induced myositis. 1529 48