Fourier transform infra-red role in diagnosis welder’s lung disease: a case report

Background. Pneumosiderosis, or welder’s lung, is a rare occupational lung disease caused by chronic inhalation of iron dust. Clinical and imaging findings often overlap with other interstitial lung diseases (ILDs), making diagnosis challenging. While the gold standard is histopathological identification of iron-laden macrophages from lung tissue or bronchoalveolar lavage (BAL) fluid, this is not always feasible in resource-limited settings. Fourier transform infrared (FTIR) spectroscopy is a reagent-free, non-destructive technique that can serve as an adjunct to detect iron oxide deposits when histopathology is unavailable. Case. A 43-year-old man, a container welder with over 20 years of welding fume exposure, presented with progressive dyspnea and productive cough. Chest imaging revealed features suggestive of ILD. Laboratory tests showed elevated ferritin and positive antinuclear antibody (ANA) and anti-double-stranded DNA (anti-dsDNA) titers without systemic autoimmune manifestations. FTIR spectroscopy performed on the BAL sample detected Fe–O bond peaks consistent with iron oxide particles. Differential diagnoses, including hypersensitivity pneumonitis, silicosis, asbestosis, and post–COVID-19 sequelae, were considered and excluded based on clinical, radiological, and laboratory findings. The patient was treated with inhaled bronchodilators and corticosteroids, advised to stop welding exposure, and referred for pulmonary rehabilitation. Conclusion. This case demonstrates the potential role of FTIR spectroscopy as a rapid, non-invasive adjunctive tool for diagnosing pneumosiderosis when histopathology is not available. It also emphasizes the importance of integrating advanced spectroscopic methods into the diagnostic work-up of occupational lung diseases in resource-limited settings.