muscle biopsy

in this report we are going to discuss the following subjects: 1. indications of muscle biopsy in which situation it can not be helpful. 2. how to take a muscle biopsy? 3. how a muscle biopsy should be operated? 4. which techniques do we need to read and interpret a muscle biopsy histologically (h & e staining, histochemical study, electron microscopy). 5. muscle disease histopathologic changes, including muscular dystrophies, congenital myopathies, neurogenic atrophies, inflammatory myopathies. definit diagnosis of a muscle disease needs clinical history, physical examination, paraclinical examination, mg and ncv, biopsy results. for an appropriate muscle biopsy interpretation a suitable patient should be chosen (in some diseases it doesn help), a suitable muscle should be chosen (it should be moderately involved) for muscle biopsy procedure, an about 1x0.8 cm muscle specimen is needed. it should be sent to the lab in less than 20 minutes in fresh state. in pathology lab it is freezed in liquid nitrogen to save the enzymatic activities. also a small fragment is fixed in gluteral aldehyde for em assessment. then it is cut in frozen section mashine and the cuts are stained with h&e.; atpase 4.2, 4.6, 9.4, modified trichrome, nadh, sdh and pas. there are more histochemical stainings which are used in special rare types of metabolic diseases. each of these staining is used for specific reasons. h&e;: for general information about the muscle structure. atpase: mostly for type fibers distribution pattern, some rods or inclusions. modified trichrome: mostly for fibrosis,inflammation, rods or inclusions. nadh: for mitochondrial abnormalities, rods or inclusions. sdh: as nadh for mitochondriopathies. pas: for glycogen storage disease. muscle diseases are generally classified into neurogenic, myogenic, muscular dystrophies, congenital myopathies, metabolic diseases, inflammatory diseases, neuromuscular disease. each of the above categories shows a specific characterizations in histochemical staining and em examinations which could help the pathologist to interpret the histologic changes more precisely.