A system of practical medicine. By American authors. Vol. 3

by Unknown

Paralysis of the arm, by interfering with the vaso-motor nerves, and thereby with the venous return of the blood, may alter the character of the pulse. A tumor external to the artery, either intra-thoracic or extra-thoracic, will produce aneurismal pulse and endarteritis, or congenital contraction of the aorta may so block the artery as to produce diminished pulse-waves. It may be said that the sphygmograph is incapable of distinguishing between an endarteritis and an aneurism.

On the other hand, the instrument is very useful in distinguishing between an aneurism and a tumor compressing an artery, because in the latter case the up-stroke and percussion wave remain normal, whereas in the former they are strongly modified, as described above. With aneurism of the ascending aorta both radials must be similarly affected, if at all, and in these cases the sphygmograph teaches very little. If the right radial is alone or mainly affected, then the aneurism involves the innominate and arch together. When an aneurism of the innominate includes the aorta, then the whole sac forms virtually a dilated aorta, and no difference in the radials will appear. Hence it follows as a corollary: Given an innominate aneurism, if the radials remain equal the aorta is certainly involved. When the left radial pulse is alone affected, the aneurism lies beyond the brachio-cephalic branch, and may or may not involve the left subclavian.

The sphygmograph is of less avail in aneurisms of the descending portion of the thoracic aorta or of the abdominal aorta. It may be of service in affording information regarding the condition of the aorta itself with reference to an operation, and it may also be of service in determining the upper limits of an aneurism under the following conditions: A case is reported which presented all the physical signs of aneurism of the descending aorta, but the sphygmograph showed that the left radial was affected, and thereby proved that the aneurism extended as high as the left subclavian at least.

While the foregoing facts prove that the sphygmograph by itself affords very inconclusive and untrustworthy evidence, yet when the presence of a tumor and other physical signs prove the existence of an aneurism, the written pulse-record will often be the guide to the accurate placement of the tumor, and thereby will often furnish decisive indications in the selection of the method of treatment.

Auscultation.—The typical aneurismal bruit is not an ordinary souffle, but it is an accentuated booming sound of a very peculiar character. Many writers describe it as a systolic jog or shock. Occasionally this bruit de battement is double—i.e. one hears two shocks, so to speak, just as one feels a double impulse. No satisfactory explanation for this reduplication of murmur has yet been given. The aneurismal murmur is almost invariably systolic. Balfour reports two cases of a diastolic murmur heard with abdominal aneurism. One of these cases was observed by himself and the other by Wickham Legg.

When this peculiar booming sound is heard over a circumscribed dull patch, it is very distinctive of aneurism, but its absence possesses no eliminative value. Many aneurismal tumors are absolutely quiet, and some of them give only a soft murmur like an ordinary cardiac souffle.

Associated with the aneurismal sound one also hears the normal heart sounds much intensified. This is peculiarly noticeable of the second cardiac sound, which acquires a ringing, booming, accentuated character when heard over an aneurism. Johnson thinks that this intensification of the heart sounds is due to the sudden tension of the walls of the sac. Balfour in referring to the same phenomenon considers it of greatest diagnostic value, and thinks that proper emphasis is not ordinarily given it.

A fundamental rule in the examination of a suspected case of aneurism is to auscult over every inch of the thorax, front and back. Not only the intrinsic signs of the tumor itself are important, but all testimony from the neighboring organs must be collected and weighed. The modification of the respiratory sounds have already been mentioned. Stokes attaches great importance to this fact, that "over one lung, more rarely over both, the breath sound has often communicated to it a peculiar sonorous vibrating quality, probably by conduction from the laryngeal stridor present."

Valvular complications of the heart are not necessarily associated with aneurism. Cases are reported, however, where a tumor is situated so near the aortic orifice as to interfere with its closure, and thus induce the ordinary phenomena of aortic insufficiency.

Of course when valvular disease is coincident with aneurism the customary signs will be added to those of the tumor, and must be carefully distinguished.