From the Guidelines
Chest myositis treatment involves immediate discontinuation of immune checkpoint inhibitors (ICPi) and initiation of high-dose glucocorticoids, with consideration of additional therapies such as IVIG and plasmapheresis in severe cases.
Treatment Approach
- For mild symptoms (G1), continue ICPi and offer oral corticosteroids, starting with prednisone at 0.5 mg/kg/day, and analgesia with acetaminophen or NSAIDs if there are no contraindications 1.
- For moderate symptoms (G2), hold ICPi temporarily, and initiate prednisone or equivalent at 0.5-1 mg/kg/d, with consideration of NSAIDs and referral to a rheumatologist or neurologist 1.
- For severe symptoms (G3-4), discontinue ICPi, and initiate high-dose systemic glucocorticoids, usually 1-2 mg/kg/day, with consideration of IVIG, plasmapheresis, and other immunosuppressant therapies if symptoms worsen or do not improve after 2 weeks 1.
Additional Considerations
- Cardiac evaluation is essential in patients with myositis, as myocarditis can be a life-threatening complication, and cardiac troponin and electrocardiography should be performed 1.
- Myositis-associated autoantibodies are mostly negative, but cases with positive ANA, antistriated antibodies, and other autoantibodies have been reported 1.
- Electromyography and MRI can be useful diagnostic tools, showing myopathic patterns and muscle enhancement, respectively 1.
- Fasciitis is increasingly reported clinically and seen on MRI findings, and IL-6R inhibitors and TNF-a inhibitors may be considered in refractory cases 1.
From the Research
Treatment for Chest Myositis
The treatment for chest myositis depends on the underlying cause of the condition.
- For idiopathic inflammatory myopathies, glucocorticoid (GC) in high doses is still the first-line treatment, often combined with another immunosuppressive agent to better control disease activity and reduce the risk of GC-related side effects 2.
- In cases of infectious myositis, treatment depends on the causative organism, with open surgical or imaging-guided drainage usually necessary in bacterial myositis 3.
- For myositis ossificans, a rare tumor of the chest wall, large tumors, suspicion of malignancy, and presence of symptoms are indications for surgical intervention, while smaller cases may resolve spontaneously or with medical treatment 4.
- In cases of secondary myositis, treatment options vary depending on the underlying cause, such as infections, drugs, rheumatologic diseases, or malignancies, and may involve specific therapies beyond immunomodulatory therapy 5.
Specific Treatment Approaches
- Immunosuppressive treatment in combination with exercise is recommended for patients with myositis to reduce disease activity and improve muscle performance 2.
- For interstitial lung disease (ILD) associated with myositis, treatment involves immunomodulation in an induction-maintenance treatment paradigm, with the option to add antifibrotics to slow the progression of established fibrosis in selected cases 6.