Reactive airways dysfunction syndrome following acute lithium hydroxide dust exposure at a battery material production plant: a case series of 16 workers.

Background: Reactive airways dysfunction syndrome (RADS) is an acute-onset form of irritant-induced asthma that occurs after a single high-concentration exposure to irritants. Although RADS has been documented for chlorine, ammonia, and acid fumes, no published case series has attributed RADS to lithium hydroxide (LiOH) dust inhalation. We report the clinical features, diagnostic evaluation, and longitudinal management of 16 workers with persistent respiratory symptoms following acute occupational LiOH exposure at a battery cathode material production facility. Case presentation: In March 2024, a silicone connector failure resulted in the leakage of approximately 50-100 kg of LiOH powder at a facility in Korea, exposing over 500 workers. Sixteen workers (15 men, 1 woman; mean age 53.4 years) with persistent respiratory symptoms were evaluated at the Department of Occupational and Environmental Medicine. Most patients presented with cough and sputum production; 56.3% (9/16) exhibited nocturnal or early-morning exacerbation. Methacholine challenge testing was performed in 10 patients, with positive results in three patients (PC20 [provocative concentration causing a 20% decline in forced expiratory volume in 1 second]: 1.36-6.74 mg/mL). By the Brooks 1985 criteria, one case was classified as definite RADS, four as probable, six as possible, and five as unlikely; American College of Chest Physicians 2008 cross-validation yielded identical classifications. Workers' compensation recipients had significantly longer follow-up (18-23 months) compared to non-recipients (1-3 months). Pharmacological management was symptom-directed, combining leukotriene receptor antagonists, mucolytics, antihistamines, and acid-suppressive therapy. Conclusions: Acute high-concentration LiOH dust inhalation may induce RADS characterized by persistent respiratory symptoms and bronchial hyperresponsiveness. The extreme alkalinity, high water solubility, and exothermic dissolution of LiOH provide a plausible mechanistic framework for airway injury. Clinicians should consider RADS in workers presenting with persistent respiratory symptoms after alkaline dust exposure, even when routine investigations are unremarkable. Attention should also be given to the psychological burden associated with prolonged, poorly recognized symptoms.