perlite and Airway-Obstruction

A 56-year-old man died following a fall resulting in complete submersion into a deep pit containing insulation material, expanded perlite. The most striking finding at autopsy was of impacted, moist pale yellow perlite that extended from the epiglottis into the main bronchi resulting in complete obstruction of the larger and smaller airways with cast formation. Perlite inhalation differs from inhalation of inert materials such as sand and wheat due to its hygroscopic properties and ability to expand forming an occlusive cast. Subsequent analyses of perlite from the worksite and within the airways indicated that hydration of perlite and adsorption of organic molecules into the perlite glass flakes had formed an interlocking, three-dimensional structure that was likely responsible for triggering a coagulation-flocculation process causing strong cohesion between the aggregates of glass flakes. This unique mechanism was likely responsible for the formation of the plug of perlite that obstructed the upper airway.

Topics: Accidental Falls; Accidents, Occupational; Airway Obstruction; Aluminum Oxide; Bronchi; Humans; Male; Microscopy, Electron, Scanning; Middle Aged; Respiratory Aspiration; Silicon Dioxide; Spectrometry, X-Ray Emission; Trachea

Expanded perlite has been assumed as simple nuisance, however during an accidental spill out in Taiwan, among 24 exposed workers followed for more than 6 months, three developed persisted respiratory symptoms and positive provocation tests were compatible with reactive airway dysfunction syndrome. During simulation experiment expanded perlite is shown to be very dusty and greatly exceed current exposure permission level. Review of literature and evidence, though exposure of expanded perlite below permission level may be generally safe, precautionary protection of short term heavy exposure is warranted.

Topics: Air Pollutants; Airway Obstruction; Aluminum Oxide; Bronchial Hyperreactivity; Dose-Response Relationship, Drug; Female; Humans; Inhalation Exposure; Occupational Exposure; Review Literature as Topic; Silicon Dioxide; Taiwan