The termaspirationpneumonia should be reserved specifically for pneumonitis resulting from aspiration of oropharyngeal or gastric contents ( table 1 ) .
This is typically due to impairment of the clearancedefenses ( eg , depressed sensorium , glottic closure , or cough reflex ) .
The character of the inoculum , underlying pulmonary conditions , and presentationassist in distinguishing the three most common clinical syndromes within the category of aspirationpneumonia , namely chemical pneumonitis , bacterial infection , and airway obstruction .
Although there may occasionally be overlap and it is often difficult to classify individual cases with certainty , this classificationscheme is essential to an understanding of aspirationpneumonia .