From the Guidelines
Inclusion body myositis (IBM) is a progressive muscle disorder characterized by muscle weakness and wasting, primarily affecting individuals over 50 years of age, and its management focuses on supportive care, including physical therapy, occupational therapy, and assistive devices, as there is no effective treatment to stop or reverse the progression of the disease. The diagnosis of IBM is based on clinical features, muscle biopsy, and laboratory tests, including muscle enzyme levels and electromyography 1.
Clinical Features and Diagnosis
The clinical features of IBM include progressive muscle weakness, wasting, and difficulty swallowing (dysphagia) 1. The diagnosis of IBM is often delayed due to its slow progression and similarity to other muscle disorders. A thorough medical history, physical examination, and laboratory tests, including muscle biopsy, are essential for diagnosing IBM 1.
Treatment and Management
The primary goal of treatment is to maintain muscle strength and function, and improve quality of life, rather than to halt or reverse the disease progression. Supportive care, including physical therapy to maintain muscle strength and function, occupational therapy to help with daily activities, and assistive devices like canes, walkers, or wheelchairs, is essential in managing IBM 1. While some physicians may try immunosuppressive medications, such as prednisone, methotrexate, or intravenous immunoglobulin, these treatments generally show limited benefit in IBM compared to other inflammatory myopathies 1.
Monitoring and Follow-up
Regular monitoring by a neurologist experienced in neuromuscular disorders is essential, with evaluations typically every 3-6 months to assess disease progression and adjust supportive measures 1. The Inclusion Body Myositis Functional Rating Scale is a validated 10-point disease-specific functional scale rating specific tasks, which can be used to monitor disease progression and response to treatment 1.
Research and Future Directions
Research into targeted therapies addressing the protein aggregation aspect of the disease is ongoing, and novel biomarkers of disease activity, such as interleukin 6 and type 1 interferon-regulated genes, may serve as indicators of disease activity in adult and juvenile myositis 1. However, currently, there is no effective treatment to stop or reverse the progression of IBM, and management focuses on supportive care to improve quality of life and maintain muscle function.
From the Research
Diagnosis of Inclusion Body Myositis (IBM)
- The diagnosis of IBM is often challenging due to its uncertain etiology and lack of effective treatment 2
- Establishing a consensus of opinion on questions relating to diagnosis and management of IBM is expected to help reduce inconsistencies in the care and resources allocated to those living with this condition 2
Treatment of Inclusion Body Myositis (IBM)
- IBM is usually refractory to immunosuppressive therapy; however, a few reports suggest that a minority of patients with IBM may have a partial, transient response or that therapy may slow progression 3
- A trial of oral prednisone can be attempted, and if no improvement is seen, oral methotrexate can be added 3
- Intravenous immunoglobulin (IVIG) has been shown to be effective in some patients, with low-dose IVIG treatment demonstrating amelioration of muscle strength and normalization of CK serum activities 4
- Other treatment options, such as sirolimus, have been investigated, but the results are inconclusive, with no significant difference in maximal voluntary isometric knee extension strength, but significant differences in favor of sirolimus for certain secondary outcomes, such as HAQ-DI, forced vital capacity, and 6-min walking distance 5
- A Cochrane review of 10 trials (249 participants) using different treatment regimens found that many of the studies did not present adequate data for the reporting of the primary outcome, and the overall trial design limitations make it difficult to say whether or not any of the drug treatments included in the review were effective 6