Abstract Introduction Interstitial lung disease (ILD) encompasses a diverse group of pulmonary disorders characterized by inflammation and fibrosis, often presenting with acute exacerbations that carry high morbidity and mortality. Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic phenotype, while hypersensitivity pneumonitis (HP) represents a non-idiopathic form triggered by environmental exposures. Management of ILD flares typically involves corticosteroids, but intravenous immunoglobulin (IVIG) has emerged as a potential adjunct in steroid-refractory cases. Case Description A 79-year-old woman with no prior lung disease presented with acute hypoxic respiratory failure and imaging consistent with fibrotic ILD. Her history included a remote 20-pack-year smoking history, alcoholic cirrhosis, and long-term use of a humidifier. She denied recent exposures to mold, pets, or birds. CT angiography revealed a subsegmental pulmonary embolism and extensive peripheral reticulation with ground-glass opacities and traction bronchiectasis. Initial management included antibiotics, azithromycin, anticoagulation, and diuresis. Despite these interventions, her condition worsened, prompting ICU transfer and initiation of high-dose methylprednisolone and IVIG. Within 48 hours, her oxygen requirements decreased significantly. Serologies later revealed positive Mycoplasma IgM (PCR negative) and a positive HP panel for Aspergillus fumigatus and Aureobasidium pullulans. High-resolution CT showed resolution of ground-glass opacities with persistent fibrosis. She was diagnosed with chronic HP and counseled on trigger avoidance. Discussion This case illustrates the diagnostic and therapeutic complexity of ILD flares. The use of IVIG in this steroid-refractory presentation led to rapid clinical improvement, supporting its potential role in acute ILD management. The positive HP panel, interpreted through a Bayesian lens considering her prior humidifier use, enabled reclassification of her disease from idiopathic to chronic HP. This reclassification significantly altered her long-term management strategy. The case highlights the importance of thorough exposure history and the diagnostic value of antigen testing in ILD. It also underscores the need for further research into IVIG’s immunomodulatory effects and its role in treating acute exacerbations of fibrotic lung disease. This abstract is funded by: None
Halla et al. (Fri,) studied this question.