Muscle and Nerve Biopsy
Helps in differentiating neurogenic and myopathic causes of limb weakness as well as specific causes of myopathy, peripheral neuropathy.
Indications: syndromes of limb weakness with cause not established by neurologic examination, family history, laboratory tests, CSF, electrodiagnostic studies, or DNA analysis.
Limitations: focal or “skip” lesions may be missed in biopsy; changes too mild to distinguish from normal or too advanced (“end-stage” muscle).
Skeletal Muscle Biopsy
Open biopsy provides better-quality specimen than needle (percutaneous) biopsy.
May help in evaluation of limb weakness, infantile hypotonia, exercise intolerance, myoglobinuria, cramps.
Identifies muscular dystrophy, polymyositis, inclusion body myositis, congenital myopathy, spinal muscular atrophy; glycolytic or oxidative enzyme defect; myopathies associated with alcohol, electrolyte disturbance, drug toxicity, carcinoma, endocrine overactivity or underactivity, long-term treatment with steroids.
Identifies denervation in motor neuron diseases, neuropathies.
Routine Histology
Neuropathy: group atrophy.
Myopathy: necrotic fibers, regenerating fibers, excessive glycogen or fat.
Polymyositis: lymphocytic infiltration.Related posts:
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