Page 497 - Textbook of Pathology, 6th Edition

3. Chest is barrel-shaped and hyperresonant. appearance is obvious in cut surface of the lung. It shows 481
4. Cough occurs late after dyspnoea starts and is associated distended air spaces in the centre of the lobules
with scanty mucoid sputum. surrounded by a rim of normal lung parenchyma in the
5. Recurrent respiratory infections are not frequent. same lobule. The lobules are separated from each other
6. Patients are called ‘pink puffers’ as they remain well by fine fibrous tissue septa. Large amount of black
oxygenated and have tachypnoea. pigment is often present in the walls of emphysematous
7. Weight loss is common. spaces. In more severe cases, distal parts of acini are also
8. Features of right heart failure (cor pulmonale) and involved and the appearance may closely resemble
hypercapneic respiratory failure are the usual terminal panacinar emphysema.
events.
9. Chest X-ray shows small heart with hyperinflated lungs. Microscopically, there is distension and destruction of the
After these general comments about morphologic and respiratory bronchiole in the centre of lobules, surroun-
clinical features of emphysema, the specific pathologic ded peripherally by normal uninvolved alveoli. The
terminal bronchioles supplying the acini show chronic
changes in individual types of ‘emphysema’ and
‘overinflation’ as classified in Table 17.4 are described below. inflammation and are narrowed.
2. PANACINAR (PANLOBULAR) EMPHYSEMA.
Morphology of Individual Types of Emphysema Panacinar or panlobular emphysema is the other common
type. In this type, all portions of the acinus are affected but
1. CENTRIACINAR (CENTRILOBULAR) EMPHYSEMA. not of the entire lung (Fig. 17.19,C). Panacinar emphysema
Centriacinar or centrilobular emphysema is one of the is most often associated with α1-antitrypsin deficiency in
common types. It is characterised by initial involvement of middle-aged smokers and is the one that produces the most
respiratory bronchioles i.e. the central or proximal part of characteristic anatomical changes in the lung in emphysema.
the acinus (Fig. 17.19,B). This is the type of emphysema that
usually coexists with chronic bronchitis and occurs Grossly, in contrast to centriacinar emphysema, the
predominantly in smokers and in coal miners’ pneumo- panacinar emphysema involves lower zone of lungs more
coniosis (page 488). frequently and more severely than the upper zone. The CHAPTER 17
involvement may be confined to a few lobules, or may be
Grossly, the lesions are more common and more severe more widespread affecting a lobe or part of a lobe of the
in the upper lobes of the lungs. The characteristic lung. The lungs are enlarged and overinflated. The Respiratory System

Figure 17.19 The anatomic regions of involvement in an acinus in major forms of emphysema.