A 7-year old boy developed myositis secondary to intramuscular injection of benzathine penicillin-G in the context of secondary prophylaxis for rheumatic heart disease. Side effects of intramuscular delivery of benzathine penicillin-G are well described and include injection site pain and inflammation, but myositis, as depicted on magnetic resonance imaging in this case, has not previously been...

We describe a case of microsporidial myositis in a healthy man from Thailand. The small subunit rRNA sequence of this microsporidium is novel and has a close phylogenetic relationship with Endoreticulatus, a genus of lepidopteran microsporidia. Myositis could be caused by more genera of microsporidia than previously known.

Myositis due to spontaneous cholesterol embolization is uncommon and usually associated with cutaneous abnormalities at presentation. A case of myositis due to cholesterol emboli is reported. The patient presented with painful weak legs, and the diagnosis was confirmed by muscle biopsy.

Objective: To investigate the clinical features, management and outcome of all children admitted to a regional hospital in Hong Kong from 2003 to 2012 because of benign acute childhood myositis. Method: A retrospective study was conducted in a regional hospital. Hospital records of children admitted from year 2003 to 2012 with diagnostic coding of myositis, rhabdomyolysis and myalgia were revie...

idiopathic inflammatory myopathies are a heterogeneous group of muscle disorders characterized by chronic muscle inflammation and progressive muscle weakness. polymyositis (pm), dermatomyositis (dm) and inclusion body myositis (ibm) are the three major subsets based on distinct clinical and histopathological features. since the pathogenesis remains unclear, therapeutic approaches actually compr...