Successful management of immunotherapy-resistant respiratory failure in anti-mitochondrial M2 antibody-positive myositis by modified lung volume recruitment therapy: A case report

Rationale: Anti-mitochondrial antibodies (AMA) M2-positive myositis can lead to severe respiratory failure. Traditional immunotherapies sometimes fail to address respiratory failure. Herein, this CARE-compliant case report described a patient with AMA-M2-positive myositis who recovered from ventilation with tracheostomy owing to immunotherapy-resistant respiratory failure to spontaneous breathing after modified lung volume recruitment (mLVR) therapy.

Patient concerns: A 60-year-old man experienced general fatigue and shortness of breath. The patient had a notable degree of proximal muscle weakness. Blood test results revealed hyperCKemia. The serum AMA-M2 antibody was positive. A muscle magnetic resonance imaging revealed diffuse abnormal hyperintensities in both lower limb muscles. Needle electromyography demonstrated fibrillation and positive sharp waves at rest with early recruitment, suggesting myogenic changes. Progressive muscle weakness and clinical findings fulfilled the criteria for definite idiopathic inflammatory myopathy. We diagnosed him with AMA-M2-positive myositis. Notably, his thoracic mobility was decreased, resulting in CO2 narcosis, requiring ventilation. Two courses of intravenous methylprednisolone for 3 days followed by oral prednisolone for myopathy. However, his respiratory function remained compromised, resulting in a tracheostomy.

Diagnoses: We diagnosed him with severe immunotherapy-resistant respiratory failure due to AMA-positive myositis that required ventilation and tracheostomy.

Interventions: To address respiratory failure, this patient underwent the mLVR therapy using the LIC TRAINER (LT). The pressure was adjusted by the operator using a bag-valve mask (BVM), starting at 1500 mL and increasing it up to a maximum of 2500 mL, while avoiding excessive airway pressure.

Outcomes: Respiratory function was evaluated by objective measures using chest wall mobility, inspiratory capacity (IC), vital capacity (VC), tidal volume (TV), and subjective measures using the visual analogue scale (VAS). Both objective and subjective scales showed significant improvements. The patient was weaned off ventilation 48 days after the initiation of mLVR therapy.

Lessons: The mLVR therapy is an effective respiratory rehabilitation for patients with weakened respiratory muscles or tracheostomy. It allows the intensity of treatment to be adjusted based on the patient's symptoms, making it both highly effective and safe. This case suggests that mLVR therapy may be effective in treating severe, immunotherapy-resistant respiratory failure in AMA-positive myositis.