The spectrum of lung disease due to chronic occult aspiration

Chronic aspiration of small volumes of oral and gastric contents can lead to lung disease. This process is less familiar than the acute aspiration syndromes, which can create confusion in terminology as well as with radiologic and pathologic definitions. In this study we analyze a series of cases of patients with chronic occult aspiration to better define the disease process. Twenty-five patients with chronic occult aspiration as defined pathologically on lung biopsy were studied by means of retrospective review of their case records. Clinical associations and radiologic and pathologic patterns were noted. Among patients with chronic occult aspiration, there was a high prevalence of gastroesophageal reflux disease (96%), esophageal dysfunction (40%), oropharyngeal/laryngeal dysfunction (40%), hiatal hernias (32%), obstructive sleep apnea (32%), and obesity (52%). The radiologic presentation was typically one of multilobar centrilobular nodularity, tree-in-bud, and airway thickening, with a subset of patients having evidence of fibrosis. The disease presented pathologically with exogenous lipoid pneumonia, poorly formed granulomas, and foreign body-type multinucleated giant cells with or without foreign material. Pathologic fibrosis was also seen. In this study, chronic occult aspiration was associated with a number of comorbid conditions and a spectrum of radiologic and pathologic patterns, which in some patients included fibrosis.