The patient was a 67-year-old male non-smoker with an unremarkable past medical history. He was admitted to our hospital with a complaint of increasing dyspnea for 3 months. His parents managed a workshop in a small town, and he had worked in processing aluminum and brass to make camera parts since he was 18 years old. He did not wear a dust respirator and worked closely to the cutting machine (Fig. 1) because of his poor eyesight.
On presentation, the patient was fully conscious with a height of 160 cm, a body weight of 47 kg, body temperature of 36.8  C and percutaneous oxygen saturation (SpO2) of 94% on room air. Physical examination revealed fine crackles upon auscultation, especially on the bilateral upper lung areas. Otherwise, there were no abnormal physical findings. Laboratory data demonstrated elevated serum levels of Krebs von den Lungen-6 (KL-6; 1631 U/mL) and surfactant protein D (SP-D; 157.3 ng/mL), compared to normal values of < 500 U/mL and < 110 ng/mL, respectively. Antinuclear and autologous antibodies were all negative. Chest X-ray showed linear and reticulonodular shadows with marked bilateral pleural thickening in the upper lung fields (Fig. 2). Chest CT indicated bilateral dense sub-pleural consolidation, bronchiectasis and ground glass opacities in the bilateral upper lobes (Fig. 3). Pulmonary function tests showed a restrictive disorder: vital capacity (VC) of 1.12 L (34.6% of predicted), forced expiratory volume in 1.0 s (FEV1) of 0.99 L (42.5% of predicted), FEV1/FVC (forced vital capacity) of 74.4% and total lung capacity (TLC) of 2.48 L (47.7% of predicted). The patient was unable to perform the diffusion test correctly. TBLB was performed with bronchoscopy to get tissue samples of the right upper lobe (B2). Bronchoalveolar lavage fluid, obtained by infusing 150 mL of saline, revealed a total cell count of 6.0 x 104/mL, comprised of 3% lymphocytes, 1% neutrophils, 2% eosinophils and 94% macrophages (Cluster of Differentiation, CD 4/8 ratio of 2.31), which was in the normal range. The biopsied specimen had fragments of bronchiolar wall with infiltration of lymphocytes in interstitial spaces; unfortunately, it did not contain alveolar tissue. A surgical diagnostic procedure was avoided due to the patient's critical respiratory condition and instead, elemental analysis was performed on the existing specimen obtained by TBLB. The content of aluminum and other particles were measured in the TBLB sample.
On elemental analysis of the biopsy specimen, a relatively high amount of aluminum was detected in comparison to trace amounts of other elements, including iron and silica (Fig.4). Based on the histological findings, the elemental analysis and the occupational history, the case was diagnosed as airway aluminosis. The patient's condition was progressively getting worse; consequently, home oxygen therapy was implemented and the anti-fibrotic agent pirfenidone was administered. Six months later, a pneumothorax occurred and chest drainage was performed; however, his condition deteriorated, and he died of hypercapnic respiratory failure 1 month later. His family did not agree to an autopsy.
High-resolution computed tomography showing severe bilateral pleural thickening with shrunken and distorted upper lobes (a, c). On the other hand, reticulonodular shadows and bronchiectasis were distributed deep inside the lower lung (b, c).