The relative frequency of common neuromuscular diagnoses in a reference center

ABSTRACT

The diagnostic procedure in neuromuscular patients is complex. Knowledge of the relative frequency of neuromuscular diseases within the investigated population is important to allow the neurologist to perform the most appropriate diagnostic tests.

Objective: To report the relative frequency of common neuromuscular diagnoses in a reference center.

Methods: A 17-year chart review of patients with suspicion of myopathy.

Results: Among 3,412 examinations, 1,603 (46.98%) yielded confirmatory results: 782 (48.78%) underwent molecular studies, and 821 (51.21%) had muscle biopsies. The most frequent diagnoses were: dystrophinopathy 460 (28.70%), mitochondriopathy 330 (20.59%), spinal muscular atrophy 158 (9.86%), limb girdle muscular dystrophy 157 (9.79%), Steinert myotonic dystrophy 138 (8.61%), facioscapulohumeral muscular dystrophy 99 (6.17%), and other diagnoses 261 (16.28%).

Conclusion: Using the presently-available diagnostic techniques in this service, a specific limb girdle muscular dystrophy subtype diagnosis was reached in 61% of the patients. A neuromuscular-appropriate diagnosis is important for genetic counseling, rehabilitation orientation, and early treatment of respiratory and cardiac complications.

RESUMO

O procedimento diagnóstico neuromuscular é complexo. O conhecimento da frequência relativa das doenças neuromusculares em uma população é importante para utilização dos testes diagnósticos mais apropriados.

Objetivo: Relatar a frequência relativa de doenças neuromusculares em um centro de referência.

Métodos: Revisão de prontuários de pacientes com suspeita de miopatia em 17 anos.

Resultados: Dentre 3412 exames, 1603 (46,98%) foram confirmatórios: 782 (48,78%) estudos moleculares e 821 (51,21%) biópsias musculares. Os diagnósticos mais frequentes foram: distrofinopatia 460 (28,70%), mitocondriopatia 330 (20.59%), atrofia muscular espinhal 158 (9,86%), distrofia muscular cintura-membros 157 (9,79%), distrofia miotçnica de Steinert 138 (8,61%), distrofia muscular face-escápulo-umeral 99 (6,17%) e outros diagnósticos 261 (16,28%).

Conclusão: Utilizando as técnicas diagnósticas atualmente disponíveis em nosso serviço, o diagnóstico específico do subtipo de distrofia muscular cintura-membros foi obtido em 61% dos pacientes. O diagnóstico neuromuscular apropriado é importante para o aconselhamento genético, orientações de reabilitação e tratamento precoce de complicações respiratórias e cardíacas.

Keywords:

diagnosis - neuromuscular diseases - biopsy - epidemiology

Palavras-chave:

diagnóstico - doenças neuromusculares - biópsia - epidemiologia

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