2C). In addition, the patient received systemic corticosteroid therapy and antibiotic treatment with amoxicillin–clavulanate. In an attempt to stimulate mucociliary clearance,4 drug discovery bronchodilatative inhalation therapy was initiated. Lung function before discharge showed normal lung volumes without obstruction. Diffusion capacity was normal. One and three months

after the accident we examined the patient in our ambulatory clinic. He then reported no respiratory symptoms. His diffusion capacity and lung volumes remained normal with an additional increase in his forced vital capacity (FVC) of nearly 1 L (111% of predicted FVC). Control chest radiography showed clearance of the bronchial opacities without signs of residual gypsum depositions or infiltrates (Fig. 1B). Due to the favorable follow-up, no further bronchoscopy was performed. To our knowledge, this is the first case report describing aspiration of large amounts of gypsum powder into the lung and its management and outcome. Current treatment Nintedanib clinical trial recommendations for gypsum inhalation or aspiration advocate supportive treatment without any published evidence.5 Our main treatment goal was to remove endotracheal and endobronchial gypsum chunks and powder without inducing additional mucosal burns by exothermic reaction upon contact with water. The entire tracheobronchial

tree is covered by an airway surface lining fluid consists of two phases with an aqueous based PIK-5 inner and viscous mucous gel outer layer.6 Some of the gypsum powder probably caused already exothermic reaction in this patient and lead to tracheobronchitis. Because of the large amount of gypsum aspirated with remaining gypsum powder chunks in the

tracheobronchial system, we expected further exothermic reaction of remaining unresolved powder upon rinsing with water. We thus carefully removed residual gypsum from the tracheobronchial tree by aspiration. Similar to our case report, one recent accidental aspiration of portland cement has been described previously.7 This construction material may contain gypsum in addition to other ingredients (different calcium salts). Like gypsum it also hardens mixed with water and can cause burns. The patient described in this case report received antibiotic therapy for bilateral pneumonia and supportive non-invasive ventilation after cement aspiration. Cement deposits were removed spontaneously. Respiratory effects of gypsum or calcium sulfate have been studied in a few animal experiments after inhalation or intratracheal administration. Major amounts of gypsum were found in dust samples along with other components after the World Trade Center Collapse.8 Mice, which were exposed to high concentrations of this dust, developed mild to moderate lung inflammation and airway hyperresponsiveness.