Correlation between specific histological and electromyographic findings in neuromuscular disorders

An attempt was made to find a correlation between specific electromyography (EMG) abnormalities with histological findings in muscle biopsies (MB) in 100 patients with neuromuscular disorders. Quantified EMG and MB with histochemistry was made in the same muscle, but on the opposite side, within a period of 3 weeks. The isolated findings of EMG and MB were analysed with a computer through a chi-square test. A statistical relation (p<0.01) was found between the isolated findings of MB and EMG in only 6.99% (39 in 558 attempts) of the abnormalities expected to occur in myopathy and denervation. Also was found 2.51% (14 in 558 attempts) of inconsistences with the current literature

Centronuclear myopathy: histopathological aspects in ten patients with chilfhood onset Miopatia centronuclear: aspectos histopatológicos em dez pacientes com a forma clínica de início na infância

Centronuclear myopathy is a rare congenital myopathy. According to the period of onset of signs and symptoms and the degree of muscular involvement three clinical forms are distinguished: severe neonatal; childhood onset; and adult onset. We describe herein the muscle biopsy findings of ten patients with the childhood onset form of the disease including three cases with ultrastructural study. The biopsies disclosed increased nuclear centralization that varied from 25 to 90% of the fibers, type 1 predominance, great variability in fiber diameters, involvement in the internal fiber's architecture, and focal areas of myofilament disorganization. The main histopathologic differential diagnoses included type I fiber predominance, congenital fiber type disproportion, and myotonic dystrophy. The histologic abnormalities in centronuclear myopathy may be due to an arrest of maturation on the fetal myotubular stage. The cause of this arrest remains elusive.<br>A miopatia centronuclear (MCN) é uma forma rara de miopatia congênita. De acordo com a época do início dos sinais e sintomas e com o grau de envolvimento muscular são distinguidas três formas clínicas: forma neonatal severa; forma de início na infância; e de início na vida adulta. São apresentados neste estudo os achados histopatológicos de dez pacientes portadores da forma de início na infância da MCN. Os fragmentos musculares foram processados através de colorações de rotina e histoquímica, e em três casos foi realizado estudo ultraestrutural. Dentre os resultados obtidos, destacou-se o aumento da centralização nuclear na fibra muscular, que variou de 25 a 90%. Adicionalmente, foram observadas predominância de fibras do tipo I, variabilidade entre o diâmetro das fibras musculares, alterações da arquitetura interna das fibras musculares e presença de áreas focais de desorganização dos miofilamentos. Devido a estes aspectos, os principais diagnósticos diferenciais considerados foram as miopatias por predominância de fibras e por desproporção de fibras, e a distrofia miotônica. As anormalidades histológicas observadas na MCN podem ser devidas a uma parada no processo maturacional do músculo esquelético na fase miotubular fetal. A causa deste defeito ainda permanece sem explicação completa