§ 7. Emphysema has been so often alluded to in the preceding pages, that a short resume of the more important points connected with it must suffice. Its great and prominent feature is dyspncea —laborious, in contradistinctiOn to hurried breathing; the respi ration is generally slow, and yet the patient is conscious of dys pncea, and makes complaint of it : there is no difficulty of articu lations; but yet he may stop in the narration of his symptoms to take breath. In its most aggravated form, the elevated shoulders, the rounded back, or the full, highly-resonant cheat, the peculiar, weak, powerless cough and voice, and the dusky, somewhat earthy or muddy aspect, are all so striking that we need scarcely insti tute a physical examination to satisfy us of the existence of em physema. Whether confined to one lung or extending to both, the phenomena of a well-marked case consist of the slight descent of the upper ribs in expiration, heaving movement, with but little expansion of the chest in inspiration, while the lower ribs are drawn inwards ; excessive resonance, and absence of breath-sound, or the substitution of prolonged distant expiration for vesicular breathing. It is of most importance as a complication of chronic bronchitis, aggravating all its evils, and permitting sometimes such an accumulation of secretion that scarcely a bubble reaches the ear, although the tubes be quite fifil.
In its minor degrees, it is often an unexpected cause as well as complication of bronchitis, especially when limited to one side of the chest : the obscurity of the symptoms sometimes leads to its being mistaken for early phthisis ; while it not unfrequently affords an explanation of the existence of asthma. When the upper lobes are chiefly implicated, absence of voice-sound is a great help in diagnosis ; but this is far from being constant : prolonged sonorous expiration is a more reliable sign, when some degree of bronchitis is present. It is unnecessary to repeat here the circum stances detailed in a former chapter (Chap. XVIII., Div. I. § 8), by which we decide whether relative dulness on percussion be due to consolidation of a portion of one lung, or to dilatation of the corresponding part of the other.
Slight general emphysema, in the absence of bronchitis, gives rise to few symptoms by which it may be detected. The patient perhaps suffers from repeated attacks of asthma, or any little cold is attended with much dyspncea : in the intervals we find that the inspiratory sound is generally weak or deficient, or a rumbling noise only is heard, which cannot be classed as inspiration at all: but on deeper breathing some little sound becomes perceptible, which is followed by a prolonged distant blowing expiration. These cases are difficult to discriminate from those in which the breath-sound is naturally weak, and where the ear may be applied over any part of the chest without hearing anything in ordinary respiration.
This is not to be regarded as an unnecessary refinement ; for where emphy sema is presentrthere is to a certain extent less chance of the lungs becoming tuberculous than when the breathing is naturally weak. Sometimes, while
the inspiration does not differ from that generally found in health, the expira tion is universally prolonged. Are such cases at all emphysematous t This is a point apparently somewhat uncertain : but I conceive that one of the elements of emphysema is a suppression of the sound of inspiration, and that its distinctness is to be regarded as exceptional, only occurring in consequence of dilatation or rigidity of some tube near the surface.
As the emphysema becomes more extensive, so do the attacks of breath lessness become more frequent and more severe ; and in addition to the ordi nary complication of bronchitis. we have two others of much importance— hypertrophy and dilatation of the right side of the heart, as a sequel of the disease of the lung, and dyspeptic symptoms, which, while they have no im mediate connection with the condition of the chest, interfere very seriously with the action of the diaphrtigm. Both tend to aggravate the dyspucea; the one by sending into the lungs a larger quantity of iolood than they can supply with air, the other by preventing the already distended lungs from receiving the limited supply which each inspiration might otherwise introduce : the for mer is permanent, the latter only temporary, in its effects upon the respiration.
The constancy of the prolonged sonorous expiration is easily explained by the loss of elasticity of the air vesicles, which deprives the lung of the power to expel any secretion existing in the tubes : hence it is that sonorous sounds are so characteristic of the disease, though in truth they depend upon bron chitia. The same circumstance explains why, with a larger amount of secre tion, the moist sounds are almost suppressed ; because the air is stagnant in the smaller tubes, and the fluid accumulates till but a few bubbles of air can pass through, and very coarse sounds only are heard at the end of inspiration, and more especially at the beginning of expiration.
§ 8. Aathma.—In speaking of the descriptions given by patients of the disease under which they are laboring, the necessity was shown of excluding any theory which the name given to the com plaint might imply, when this name comprises not only the facts of the case but the notions acquired of their causation. This is especially true of asthma ; and when a patient calls himself astir matic,it must be our first object to ascertain whether the dyspncea be habitual and of long continuance, or whether there be any paroxysmal oharaoter in the attack. We restrict the term to those c,ases in which the difficulty of breathing occtuv distinctly in paroxysms, of longer or shorter duration, which at their worst cannot exceed a eouple of days, and more generally last only a few hours.