Aspiration Pneumonia/Bronchitis

Swallowing is an organized bodily function that occurs in four phases and involves the fine coordination of 30 different pairs of nerves and muscles. Problems arise when there are structural and/or functional defects in this highly coordinated process. “Aspiration” refers to an inadvertent inhalation of oropharyngeal secretions/gastric contents below the level of the true vocal cords into the respiratory tract. Almost half of healthy adults aspirate routinely during the night; however, several structural and functional abnormalities in the aerodigestive tract predispose certain populations to a higher risk. The elderly are especially vulnerable. Age-related structural abnormalities (such as cervical osteophytes, Zenker’s diverticulum, esophageal strictures) can interfere with normal swallowing and lead to aspiration. Furthermore, nursing home residents harbor potentially dangerous pathogens due to poor oral hygiene—that if aspirated can lead to pneumonia. Other high-risk groups include those with bowel dysmotility (bowel obstruction, scleroderma, etc.) or altered consciousness (seizure disorder, alcohol use, or other drug abuse). Aggressive use of acid-suppressive medications (PPIs, H2 receptor blockers) also increases risk for aspiration pneumonia, both in the community and in critically ill mechanically ventilated. About 5–15% of all community-acquired pneumonia is secondary to aspiration and aspiration pneumonia carries a higher 30-day mortality when compared to other community-acquired pneumonias. A diagnosis requires a high index of suspicion and can be challenging. Diagnostic testing includes a bedside evaluation of swallowing, use of a modified barium swallow study, video fluoroscopic swallow study, or a flexible endoscopic evaluation of swallowing (FEES). Aspiration can cause a wide variety of clinical syndromes including chemical pneumonitis, aspiration pneumonia, and adult respiratory distress syndrome (ARDS). It is important to differentiate aspiration pneumonitis from pneumonia—as the latter involves pathogenic bacteria and entails antimicrobial treatment. Unchecked aspiration often leads to chronic lung damage (diffuse aspiration bronchiolitis, refractory asthma, bronchiectasis, lipoid pneumonias, and even idiopathic pulmonary fibrosis). All aspiration does not necessitate antimicrobial therapy and it is important to identify risk factors that predispose patients to a higher bacterial burden in the event of an aspiration (i.e., chronic alcoholism, bowel dysmotility, stroke). These patients are likely to benefit from timely initiation of empiric antimicrobial therapy.