In the sacculated form, on the other hand, the bronchial wall generally presents a thin and atrophied appearance, the mucous membrane undergoing but little change, except that the stretching to which it has been subjected gives it a smooth and shining look. This difference in the degree of thickening of the bronchial walls in the two forms of dilatation is in part due to the fact that in the saccular variety the enlargement in calibre is far greater than it is in the cylindrical form for a corresponding extent of a tube, so that its wall is much more stretched and attenuated, and thus the tendency to hypertrophy which has play in the cylindrical form is more than overcome in the saccular. But the chief reason of the difference in the state of the walls in the two forms of dilatation is found in the different modes in which they are respectively brought about, as already described.
DIAGNOSIS.—It has been shown that the determination of the existence of bronchial dilatation is at times one of the most difficult problems in diagnosis, from the fact that the auscultatory signs belonging to it may be equally met with in other affections, especially in pulmonary phthisis. The diagnosis is to be established, when this is possible, only by a careful consideration of the physical signs in connection with the general symptoms, so that the sources of doubt arising from the one set of phenomena may be as far as possible corrected by the other. These signs and symptoms, and the various affections to be discriminated by them, have been sufficiently set forth under the head of Symptomatology. While in this way a clear conclusion may be reached in many cases, yet there are others in which, notwithstanding the utmost care, there may still be a doubt as to whether the symptoms and signs indicate a dilated tube or a pulmonary cavity.
PROGNOSIS.—The prognosis of bronchial dilatation is directly connected with that of the affections which chiefly give rise to it—viz. chronic bronchitis and fibroid phthisis. When chronic bronchitis has lasted long enough to cause dilatation, it is seldom if ever cured, and, though improvement may take place from time to time in its symptoms, yet the dilated bronchi can hardly undergo diminution in their size. And in fibroid phthisis, while the progress of the disease is often very slow, yet it is on a downward grade, and the connective-tissue contraction giving rise to the dilatation increases with the advance of the malady.
TREATMENT.—The treatment of cases of bronchial dilatation resolves itself in great degree into that of the underlying and causal diseases on which it depends. As regards methods specially directed to the areas of dilatation, they consist of alterative, astringent, stimulant, and antiseptic remedies, either administered by the stomach or used by the process of inhalation. Cough may be allayed with the syrup of lettuce containing in each dose from 1/8th to ¼th of a grain of sulphate of codeia or 10 or 12 drops of the spirit of chloroform. If expectoration is very profuse, sulphate of atropia, in the dose of 1/100th to 1/80th of a grain, or the extract or tincture of belladonna, may be used. Turpentine and eucalyptol have a controlling influence over this symptom, and are specially beneficial if the bronchial secretion is fetid. They may be given by the mouth in the dose of minim v–xx in emulsion, and applied also by inhalation of their vapor or by spray. Inhalations of solutions of carbolic acid, minim j–x to an ounce of water, are more effective than anything else in checking fetor of the expectoration and the breath. This agent may also be administered by the mouth in the dose of fluidrachm j–iv of a 1 per cent. solution.
EMPHYSEMA.
BY SAMUEL C. CHEW, M.D.
DEFINITION.—The term emphysema is derived from [Greek: emphysaô], to inflate, and signifies an increased amount of air in a part or the whole of one or both lungs. Accordingly as the situation of this excess of air is (a) in the air-vesicles or (b) in the connective tissue between the lobules, emphysema is divided into Vesicular emphysema and Interlobular or extra-vesicular emphysema.