Abstract Introduction Inclusion body myositis (IBM) is a slowly progressive inflammatory myopathy that primarily affects proximal muscles, although cardiac, respiratory, and gastrointestinal, and distal muscle involvement can also occur 1. We present a case of acute hypercapnic and hypoxic respiratory failure (AHHRF) secondary to diaphragmatic weakness in a patient with IBM. Case Presentation A 60-year-old man with type 2 diabetes mellitus and inclusion body myositis diagnosed two weeks prior, as well as frontotemporal dementia, presented with shortness of breath and severe hypoxia (SpO2 in the 40s). On arrival, his HR was 107 bpm, BP183/105 mmHg, and SpO2 42% on room air. He was lethargic, no JVD, and decreased breath sounds bilaterally. Arterial blood gas analysis showed pH 7.01, pCO2 110 mmHg, and lactate 6.1 mmol/L. Other notable labs were WBC 22 × 10³/µL (4-11 × 10³/µL) and normal procalcitonin. The patient was intubated and started on empiric broad-spectrum antibiotics. After initial clinical improvement, a trial of extubation was unsuccessful. Pulse dose corticosteroids were started for presumed diaphragmatic weakness secondary to IBM. Following a failed second extubation attempt, a tracheostomy was performed. The patient was gradually weaned to a tracheostomy collar during the day and pressure-regulated volume control (PRVC) ventilation at night and was discharged home, four weeks after presentation. He subsequently experienced three additional admissions for recurrent AHHRF. Discussion IBM is diagnosed through characteristic clinical features, imaging findings, and confirmatory muscle biopsy. Respiratory complications most often arise from aspiration or pneumonia, while AHHRF due to respiratory muscle weakness is rare and typically occurs in advanced disease 2. This patient’s recurrent AHHRF episodes, in the absence of infection or aspiration, indicate diaphragmatic and respiratory muscle weakness as the primary etiology. Persistently reduced forced vital capacity (FVC) further supports this mechanism and aligns with previously reported cases. This case underscores the importance of early recognition of respiratory involvement in IBM through routine PFTs and the potential role of noninvasive ventilation in improving clinical outcomes and quality of life. References 1. Ashif Jethava, Ali S, Dasanu CA. Primary respiratory failure due to inclusion body myositis: think outside the box. PubMed. 2013;77(3):155-158. 2. Lelièvre M, Hudson M, Botez SA, Dubé B. Determinants and functional impacts of diaphragmatic involvement in patients with inclusion body myositis. Muscle 63(4):497-505. This abstract is funded by: None
Rathnam et al. (Fri,) studied this question.