HISTORY.—These two affections are different pathologically and anatomically, vesicular emphysema being a much more common and important affection than the interlobular form. The distinction between the two forms was first drawn by Laennec. Previously to his time the essential difference between them was unknown; and, as the accurate diagnosis of the disease can be made only by auscultation, its existence was no doubt very often entirely overlooked. It has been remarked by Rokitansky1 that "had Laennec done nothing else for medical science, his discovery of this diseased condition, and of the causes giving rise to it, would have sufficed to render his name immortal."
1 Path. Anat., vol. iv. p. 53, Am. ed.
VESICULAR EMPHYSEMA.
Vesicular emphysema may be defined as an absolute or relative increase in the amount of air contained in the vesicles of a part or the whole of one or both lungs. As a substantive disease it occurs in two principal forms—hypertrophic and atrophic; but besides these it is met with as a secondary affection due to other diseases and limited to certain areas of the lungs, sometimes acute and sometimes chronic in its production and duration. It will therefore be best to consider the disease under the following different forms:
1st. Acute lobular emphysema;
2d. Chronic lobular emphysema;
3d. Hypertrophic lobar emphysema;
4th. Atrophic lobar emphysema.
1. Acute Lobular Emphysema.
This form of the disease is the result of the rapid distension beyond their natural size of air-vesicles which had previously been healthy. It is most frequently met with in children and as the consequence of bronchitis or whooping cough. The paroxysms of cough occurring in these affections, especially in the latter, are attended by deep inspirations, by which the vesicles are directly distended, and by violent expiratory efforts, with closure of the glottis, so that the air is forced into those portions of the lungs where there is least resistance, particularly at the apex and along the margins. In a large proportion of cases of acute lobular emphysema, when the distending cause is removed by the cessation of the cough, the vesicles return to their normal size through their natural elasticity, which has not been destroyed. But in some cases, when the cough has been of unusual violence or of very long duration, the change may be permanent through loss of this elasticity, and thus a form of chronic lobular emphysema is produced.
SYMPTOMS AND SIGNS.—Unless emphysema of this form is extensive and extreme in degree, it is not attended with symptoms additional to those of the affections giving rise to it. When very great it may occasion increased percussion resonance.
TREATMENT.—The treatment is only what is required by the causal affections.