PATHOPHYSIOLOGY OF PNEUMONIA

The lung is continually exposed to infectious challenges requiring an intricate system of defense mechanisms that facilitates the eliminatio n of pathogens and prevents the development of infection. Both the upp er airway and the lower respiratory tract have mechanical, humoral, an d cellular mechanisms in place to protect the airways from invading mi croorganisms. Impairment in any arm of this system can result in a pre disposition of the host to respiratory infections. Defects may be cong enital, acquired, or iatrogenic. Understanding how these defects lead to infection may result in the development of innovative therapies, as well as preventive strategies.