Inclusion Body Myositis

Abstract

Objective: This article addresses the clinical presentation, diagnostic workup, and management of patients with inclusion body myositis (IBM). It also provides an overview of the clinical trial landscape and explores future directions in the pursuit of an effective treatment for the disease.

Latest developments: Muscle biopsy remains the cornerstone of the diagnosis, and cytosolic nucleotidase 1A antibodies and muscle imaging have been increasingly used to support the diagnosis. The 2024 European Neuromuscular Centre diagnostic criteria offer a new diagnostic framework that integrates these developments. The clinical trial landscape for IBM remains limited, and the complex nature of the underlying pathophysiology of IBM and other diseases of aging presents a significant challenge for the development of effective treatments.

Essential points: IBM is a disease of aging that is more prevalent in males. It is characterized by slowly progressive weakness, predominantly affecting deep finger flexors and quadriceps muscles, with a predilection for swallowing and respiratory muscles. However, this clinical phenotype is not specific to IBM, as other inherited and acquired myopathies may present similarly. Furthermore, atypical presentations of IBM occur and may manifest with a wide range of weakness patterns, most commonly with isolated dysphagia. The diagnosis of IBM requires the integration of historical, clinical, and laboratory data. Management consists of a multidisciplinary approach to address comorbidities and potential complications. Untangling the complexity of aging-related disorders will help advance the field in IBM and facilitate the discovery of effective treatments.