Aspiration of particulate matter is a well-recognized complication in debilitated patients at autopsy but is not widely recognized in surgical pathology material. We have encountered a surprising number of cases on biopsy or resection specimens, and most were unsuspected clinically and pathologically. This study was undertaken to clarify clinical and pathologic features that facilitate the diagnosis of food/particulate matter aspiration pneumonia. Fifty-nine patients were identified with an average age of 57 (range 26 to 85), and a male/female ratio of 2:1. Common presenting symptoms (information available in 36 cases) included dyspnea (14), fever (9), and cough (6). A history of recurrent pneumonia was present in 9. Radiographic data were available in 34 cases. Bilateral infiltrates or nodules were found in 17 cases, whereas the changes were unilateral in 17. Solitary nodules clinically suspicious for neoplasm were present in 13. Aspiration was suspected clinically in only 4 of the 45 cases in which the clinical impression or differential diagnosis was stated. Predisposing factors for aspiration were identified in 32 patients, including esophageal or gastric causes (19), drug use (10), and neurologic conditions (6). Histologically, bronchiolitis obliterans-organizing pneumonia was present in 52 (88%) cases, usually in combination with multinucleated giant cells, acute bronchopneumonia/bronchiolitis, and/or suppurative granulomas. Foreign material was identified in all cases, including most commonly vegetable or food remnants (54 cases), and less often talc or microcrystalline cellulose (7), crospovidone (4), and kayexalate (2). Particulate matter aspiration pneumonia is a more common cause of lung infiltrates and nodules than generally appreciated. The diagnosis should be suspected when multinucleated giant cells, acute bronchopneumonia/bronchiolitis, and/or suppurative granulomas are found in a background of bronchiolitis obliterans-organizing pneumonia. The presence of foreign material confirms the diagnosis.
"We and others    have found that histopathological analysis may support a diagnosis of reflux and aspiration in selected cases of pulmonary parenchymal injury. A distinct histological pattern of " centrilobular fibrosis " has been described that is possibly associated with GER and aspiration . "
[Show abstract][Hide abstract] ABSTRACT: The histological counterpart of idiopathic pulmonary fibrosis is usual interstitial pneumonia, in which areas of fibrosis of various ages are interspersed with normal lung. This pattern could be explained by repeated episodes of lung injury followed by abnormal wound healing responses. The cause of the initiating alveolar epithelial injury is unknown, but postulated mechanisms include immunological, microbial, or chemical injury, including aspirated gastric refluxate. Reflux is promoted by low basal pressure in the lower oesophageal sphincter and frequent relaxations, potentiated by hiatus hernia or oesophageal dysmotility. In susceptible individuals, repeated microaspiration of gastric refluxate may contribute to the pathogenesis of IPF. Microaspiration of nonacid or gaseous refluxate is poorly detected by current tests for gastroesophageal reflux which were developed for investigating oesophageal symptoms. Further studies using pharyngeal pH probes, high-resolution impedance manometry, and measurement of pepsin in the lung should clarify the impact of reflux and microaspiration in the pathogenesis of IPF.
Pulmonary Medicine 01/2011; 2011(2090-1836):634613. DOI:10.1155/2011/634613
[Show abstract][Hide abstract] ABSTRACT: This paper presents experimental surface acoustic wave velocity dispersion data, obtained from thin film tungsten silicide layers (500-2500 A) cosputtered on single-crystal silicon wafers, as a function of various technologically relevant thermal processing treatments. The velocity dispersion data was determined using an acoustic microscope operating at 375 MHz via the acoustic material signature (AMs) technique. Transmission electron microscopy and X-ray diffraction analysis were used to characterise the microstructure of these thin films. Simple mathematical expressions for the transmission of a surface wave along a varying polycrystalline structure were then used to interpret the experimental data, the approximate model thus developed enables us to access the interface conditions between grains in the material.
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