Increased bronchoalveolar lavage fluid tin content in stannosis

Abstract

Stannosis is a rare non-fibrotic pneumoconiosis that follows the chronic inhalation of tin particles. Apart from occupational history and radiographic findings, no diagnostic criteria exist for stannosis. Therefore, analysis of bronchoalveolar lavage fluid (BALF) to support stannosis might be of significant value. We present a case of a 74-year-old male patient, who developed progressive dyspnea and dry cough 35 years after working full-time as a tinner for 17 years. His post-bronchodilator forced vital capacity and forced expiratory volume in one second were 111% and 108% predicted, respectively, accompanied by a disproportionately low diffusing capacity of the lung (34.4% predicted). Contents of tin, lead and copper were measured in both the BALF and the systemic circulation by electrothermal atomic and flame absorption spectrometry. The patient had a 38.5-, 48.5-, 88- and 85- fold higher BALF concentration of tin than did four male individuals (controls) without stannosis or an exposure to other heavy metals (crude figures and standardized for total protein, albumin, and potassium contents, respectively). Moreover, there was no difference in the BALF concentrations of lead and copper, or any of the heavy metals in the peripheral blood stream between the patient and the controls. The relative coefficient of excretion of 24.9 for tin in the patient and of <1 both for tin in the controls and for other metals in the patient, as well as for all metals in the controls refers to the deposition of tin locally into the lungs of the patient via chronic inhalation. This case study indicates that weighed measurement of tin in the BALF could provide significant support to the clinical diagnosis of stannosis.