What is the pathophysiology of aspiration in dysphagia?

Updated: Mar 20, 2020
  • Author: Nam-Jong Paik, MD, PhD; Chief Editor: Elizabeth A Moberg-Wolff, MD  more...
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Answer

As previously mentioned, aspiration is the passage of food or liquid through the vocal folds. People without swallowing abnormalities routinely aspirate microscopic amounts of food and liquid. Gross aspiration, however, is abnormal and may lead to respiratory complications, including pneumonia. (See the images below.) [14]

Lateral projection of the videoprint of a videogra Lateral projection of the videoprint of a videographic swallowing study shows residues on the vallecula (Vr) and pyriform sinuses (Pr) and a small amount of aspirated liquid barium in the trachea (As).
Lateral projection of the videoprint of a videogra Lateral projection of the videoprint of a videographic swallowing study shows subglottic aspiration.
Delayed posteroanterior chest image shows aspirati Delayed posteroanterior chest image shows aspiration of liquid barium into the distal bronchus.

Several factors influence the effects of aspiration: quantity, depth, physical properties of the aspirate, and pulmonary clearance mechanisms.

Aspirating material into the distal airways is more dangerous than aspiration into the vocal folds. Solid food may cause fatal airway obstruction, and acidic material is dangerous because the lungs are highly sensitive to the caustic effects of acid. Aspirating material laden with infectious organisms or even normal mouth flora can cause bacterial pneumonitis.

Pulmonary clearance mechanisms include ciliary action and coughing, with aspiration normally provoking a strong reflex cough. If sensation is impaired, silent aspiration may occur.

The severity of aspiration can be described by estimating the percentage of the total bolus aspirated or by estimating the depth of bolus invasion into the airway. The Eight-Point Penetration-Aspiration Scale is an example of an estimation tool. [15]


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