Muddy Water Pneumonitis: An Emerging Occupational Lung Disease in Professional Divers.

Chronic occupational exposure to contaminated aquatic environments is an underrecognized cause of progressive lung injury. Recurrent aspiration of sediment-rich river water can lead to chronic inflammatory lung injury with possible environmental pathogen colonization and destructive lung disease, even in immunocompetent individuals. A 35-year-old non-smoking professional diver in a tropical mangrove region of the Sundarban, Bangladesh, with 17 years of exposure performing 10-15 daily dives in muddy saline mangrove water, presented with 1 year of progressive exertional dyspnea and intermittent cough. Water aspiration during mud collection was frequent; four coworkers reported similar symptoms. SpO2 was 93% at rest, dropping to 89% after 700 m on a 6-min walk test, indicating exercise-induced desaturation despite preserved walking distance. Digital clubbing and bilateral coarse crepitations were present. HRCT showed diffuse nodules and a left upper lobe cavitary lesion; Mantoux and Interferon gamma release assay were negative. Pulmonary function revealed severe restrictive defect (TLC 39%, FVC 25%, DLCO 36%, RV/TLC 48%). BAL grew Acinetobacter sensitive to meropenem and amikacin. After 7 days of IV therapy, symptoms improved, but domiciliary oxygen was not feasible. The patient died 1 month later. Muddy water pneumonitis can cause progressive necrotizing lung injury in divers, likely representing a multifactorial process involving environmental particulate exposure with superimposed infection. It was worsened by socioeconomic constraints and highlights the need for occupational protection and early recognition.