RESUMO
Idiopathic inflammatory myopathies (IIM) are a heterogenous group of treatable myopathies. Patients present mainly to the rheumatologist and neurologists, complaining of acute or subacute onset of proximal weakness. Extramuscular manifestations may occur, including involvement of the lungs, skin, and joints. Classically, the diagnosis used to be made based on the creatine kinase level increase, abnormalities in electroneuromyography and presence of inflammatory infiltrates in the muscle biopsy. Recently, the importance of autoantibodies has increased, and now they may be identified in more than half of IIM patients. The continuous clinicoseropathological improvement in IIM knowledge has changed the way we see these patients and how we classify them. In the past, only polymyositis, dermatomyositis and inclusion body myopathy were described. Currently, immune-mediated necrotizing myopathy, overlap myositis and antisynthetase syndrome have been considered the most common forms of IIM in clinical practice, increasing the spectrum of classification. Patients previously considered to have polymyositis, in fact have these other forms of seropositive IIM. In this article, we reviewed the new concepts of classification, a practical way to make the diagnosis and how to plan the treatment of patients suffering from IIM.
Assuntos
Dermatomiosite , Doenças Musculares , Miosite , Polimiosite , Autoanticorpos , Dermatomiosite/diagnóstico , Dermatomiosite/patologia , Humanos , Miosite/diagnóstico , Miosite/terapia , NeurologistasRESUMO
Desmin (DES) is the main intermediate muscle filament that connects myofibrils individually and with the nucleus, sarcolemma, and organelles. Pathogenic variants of DES cause desminopathy, a disorder affecting the heart and skeletal muscles. We aimed to analyze the clinical features, morphology, and distribution of desmin aggregates in skeletal muscle biopsies of patients with desminopathy and to correlate these findings with the type and location of disease-causing DES variants. This retrospective study included 30 patients from 20 families with molecularly confirmed desminopathy from 2 neuromuscular referral centers. We identified 2 distinct patterns of desmin aggregates: well-demarcated subsarcolemmal aggregates and diffuse aggregates with poorly delimited borders. Pathogenic variants located in the 1B segment and the tail domain of the desmin molecule are more likely to present with early-onset cardiomyopathy compared to patients with variants in other segments. All patients with mutations in the 1B segment had well-demarcated subsarcolemmal aggregates, but none of the patients with variants in other desmin segments showed such histological features. We suggest that variants located in the 1B segment lead to well-shaped subsarcolemmal desmin aggregation and cause disease with more frequent cardiac manifestations. These findings will facilitate early identification of patients with potentially severe cardiac syndromes.
Assuntos
Cardiomiopatias , Cardiomiopatias/genética , Cardiomiopatias/patologia , Desmina/genética , Humanos , Músculo Esquelético/patologia , Mutação/genética , Fenótipo , Estudos RetrospectivosRESUMO
ABSTRACT Idiopathic inflammatory myopathies (IIM) are a heterogenous group of treatable myopathies. Patients present mainly to the rheumatologist and neurologists, complaining of acute or subacute onset of proximal weakness. Extramuscular manifestations may occur, including involvement of the lungs, skin, and joints. Classically, the diagnosis used to be made based on the creatine kinase level increase, abnormalities in electroneuromyography and presence of inflammatory infiltrates in the muscle biopsy. Recently, the importance of autoantibodies has increased, and now they may be identified in more than half of IIM patients. The continuous clinicoseropathological improvement in IIM knowledge has changed the way we see these patients and how we classify them. In the past, only polymyositis, dermatomyositis and inclusion body myopathy were described. Currently, immune-mediated necrotizing myopathy, overlap myositis and antisynthetase syndrome have been considered the most common forms of IIM in clinical practice, increasing the spectrum of classification. Patients previously considered to have polymyositis, in fact have these other forms of seropositive IIM. In this article, we reviewed the new concepts of classification, a practical way to make the diagnosis and how to plan the treatment of patients suffering from IIM.
RESUMO As miopatias inflamatórias idiopáticas (MII) são um grupo heterogêneo de miopatias tratáveis. Os pacientes procuram principalmente o reumatologista e o neurologista, queixando-se de início agudo ou subagudo de fraqueza proximal. Manifestações extramusculares podem ocorrer, incluindo envolvimento dos pulmões, pele e articulações. Classicamente, o diagnóstico era feito com base na elevação dos níveis de creatina quinase, anormalidades na eletroneuromiografia e presença de infiltrados inflamatórios na biópsia muscular. Recentemente, a importância dos autoanticorpos aumentou, e agora eles podem ser identificados em mais da metade dos pacientes com MII. A contínua melhora clínico-soropatológica no conhecimento do MII mudou a forma como vemos esses pacientes e como os classificamos. No passado, apenas polimiosite, dermatomiosite e miopatia por corpos de inclusão eram descritas. Atualmente, a miopatia necrosante imunomediada, a miosite de sobreposição e a síndrome antissintetase têm sido consideradas as formas mais comuns de MII na prática clínica, aumentando o espectro de classificação. Pacientes previamente considerados como portadores de polimiosite, na verdade, têm uma dessas outras formas de MII soropositivas. Neste artigo, revisamos os novos conceitos de classificação, uma forma prática de fazer o diagnóstico e como planejar o tratamento de pacientes que sofrem de MII.
RESUMO
Sporadic inclusion-body myositis (IBM) is the most common myopathy in individuals over 55 years of age. However, in many cases, the diagnosis is neglected. Its main findings include progressive muscle weakness, normal or low levels of serum creatine kinase, and the absence of a response to immunosuppression. Muscle biopsy shows inflammatory reaction in association with degenerative changes of the muscle fibers. We report a typical case of IBM, in which diagnosis was possible only after three muscle biopsies. The challenges to confirm histological diagnosis and the caution to avoid repeating tests are discussed.
A miosite por corpos de inclusão (MCI) esporádica é a miopatia mais comum acima dos 55 anos de idade. No entanto, em muitos casos, o diagnóstico é negligenciado. Os principais achados incluem fraqueza muscular progressiva, níveis séricos normais ou levemente elevados de creatinoquinase (CK) e ausência de resposta à imunossupressão. A biópsia muscular evidencia reação inflamatória associada com alterações degenerativas das fibras musculares. Apresentamos um caso típico de MCI cujo diagnóstico foi obtido após a realização de uma terceira biopsia muscular. Discutimos os desafios para a confirmação do diagnóstico histológico e os cuidados que podem evitar repetições do exame.