Most are saccular; some are small and spring from the aorta just above the aortic ring. Another variety springs from the anterior and upper aspect of the aorta in the form of large tumors, or from the descending aorta and the lower surface of the arch, compressing the trachea or bronchi.
In intrathoracic aneurism clubbing of the fingers and incurving of the nails of one hand may also be observed, even when no venous engorgement is present.
Sudden death may be induced by rupt ure into the, pleura or a small and latent aneurism bursting into the oesophagus. The spinal cord may be compressed and give rise to disorders of locomotion.
Differential Diagnosis.—When the an eurism is in the thorax, the conditions with which it may be confounded are: 1. Violent throbbing of the arch through marked aortic insufficiency.
2. Displacement of the heart through the deformity caused by spinal curvature.
3. Pulsating pleurisy can be differ entiated by means of a fine, hypodermic needle. In pulsating pleurisy the throb bing is usually wide-spread and diffuse; in aneurism there is a firm, heaving dis tension and a diastolic shock.
4. Tumors. In deep tumors the pain is likely to be more severe. Pressure phenomena are most common in aneu rism. When the abdominal aorta is in volved, neurotic pulsation of the latter should be suspected.
Almost none of the symptoms are due to the aneurism itself, but most are produced by the influence of the tumor upon neighboring structures. A certain amount of dull pain may be due to the distension of the sac-wall itself; but this is usually entirely overshadowed by that produced by alterations in parts in the neighborhood. For our diagnosis we must depend not so much upon the physical signs of an arterial tumor as upon those due to an abnormal growth of whatever nature.
The typical signs of aneurism may be said to be tumor, expansile pulsation, thrill, bruit, and shock. Tumor is fre quently absent; expansile pulsation is, in many situations, impossible of detec tion; thrill is a very uncertain sign; bruit is as often absent as present; while shock, whether diastolic or systolic, is frequently absent. F. A. Packard (Mass. Med. Jour., Oct., '07).
Radioscopy is of value in the study of aneurisms of the arch of the aorta, but of little use in case the descending aorta is affected, as under the latter conditions the of the heart overlies that of the aneurism. G. R. Murray (Prac
titioner, Feb., '08).
The fluoroscope in diagnosing anev 'isms of the aorta. While aneurisms usually throw a shadow beside the heart, which can be seen to enlarge in all di rections with each heart-beat, this must not, however, be regarded as pathogno monic. Case in which, although the shadow was well defined and the pulsa tion marked, necropsy showed carcinoma of the cardia with extreme dilatation of the esophagus above, thus simulating aneurism. G. Kirchgaesser (Miinchener med. Woch., May 8, 1900).
Case of aneurism of the aorta in which pain along the intercostal nerves, on both sides, with marked disturbances of sensibility,—i.e., intercostal neuritis, due to pressure,—was the main symp tom of the aneurism for months. Sub jective symptoms were entirely absent. Frick (Wiener klin. Woch., June 20, 1901).
The diagnosis of aortic aneurism still remains, in obscure cases, a difficult one, and even the x-ray examination may be misleading. Attention called to the frequency with which, in aneurism of the arch, the left supraclavicular groove is obliterated or even bulges, and the left external jugular is obviously fuller than the right. The anatomical reason lies simply in the compression of the left innominate vein as a result of the dilated arch. A mediastinal tumor may have the same effect, but dilatation in cases of aortic insufficiency is appar ently seldom sufficient to effect com pression. Dorendorff (Deutsche med. Woch., Nov. 31, 1902).
Etiology. — Aortic aneurism is espe cially due to alcohol, syphilis, and over work. Sudden muscular exertion may lacerate the media. The etiological fac tors of aneurisms in general may all be considered as capable of promoting aneu rism of the aorta.
Treatment. — All methods should be aided by rest in bed and proper diet.
It is unnecessary to give large doses of potassium iodide, viz.: from 10 to 20 grains thrice daily. This drug relieves pain, causes thickening and contraction of the sac, and lowers the blood-press ure. Pain may sometimes be relieved by anodyne plasters or embrocations, but morphine may be necessary in the final stages. Ice poultices, recommended by some to relieve pain, are liable to cause gangrene of the skin, owing to deficient circulation. Chloroform may be used in dyspncea. Small, but repeated, venesec tions are highly recommended for the latter symptom.