What is the primary pathologic change that occurs in interstitial lung disease?

(Answer to Q. 1)  ANS: A
The lung must respond to the damage and repair itself. If the exposure to the causative agent per-sists or if the repair process is imperfect, the lung may be permanently damaged with increased interstitial tissue replacing the normal capillaries, alveoli, and healthy interstitium.

(Answer to Q. 2)  ANS: C
Sarcoidosis is not an occupationally related ILD (see Figure 26-1).

(Answer to Q. 3)  ANS: C
Gas exchange is impaired owing to ventilation/perfusion mismatching, shunt, and decreased dif-fusion across the abnormal interstitium.

(Answer to Q. 4)  ANS: A
Mr. Jones' medical history suggests chronic bronchitis exacerbated by a respiratory infection such as acute bronchitis, flu, or pneumonia. Chronic bronchitis is defined in clinical terms as a condi-tion in which chronic productive cough is present for at least 3 months per year for at least 2 consecutive years.

(Answer to Q. 5)  ANS: D
Mr. Jones' dyspnea at rest and chronic sputum production requires further evaluation. A pre-post PFT study is indicated at this time to (1) differentiate his COPD diagnosis between emphysema, chronic bronchitis and asthma and (2) assess possible airway obstruction and its reversibility lev-el. A chest x-ray and arterial blood gas analysis are also indicated in the presence of dyspnea and due to this patient's occupational history.

(Answer to Q. 6)  ANS: C
The term interstitial lung disease (ILD) refers to a broad category of lung diseases rather than to a specific disease entity. It includes a variety of illnesses with diverse causes, treatments, and prognoses. These disorders are grouped together because of similarities in their clinical presenta-tions, plain chest radiographic appearance, and physiologic features.