Many sacculated aneurisms are prob ably true aneurisms at first, but, on in creasing in size, the inner coats of the artery rupture and the aneurism becomes a false aneurism.
In tubular or fusiform aneurism the vessel is also elongated. Several tubular aneurisms may exist in the course of the same vessel, the artery remaining healthy between them.
In tubular aneurism the three coats of the artery are preserved, but the middle coat, not undergoing hyperplasia, its ele ments no longer form a continuous layer, but are separated one from another. The sac, in this form of aneurism, being, in reality, only an enlargement of the lumen of the vessel, exposed to the full current of the blood, no laminated fibrin is found in it.
As compared to other tissues, the skin resists longest the pressure from aneu rism.
Aneurisms are most common in the thoracic aorta (ascending and transverse portions) and next in the popliteal, ca rotid, subclavian, innominate, and axil lary. The most important aneurisms on small arteries are those in the brain, lungs, and heart.
Case of aneurism at apex of heart; the patient, a woman, S6 years of age, had never complained of any cardiac trouble, and death resulted from apo plexy. The autopsy showed a small an eurism at the apex of the heart, with complete absence of cardiac muscle at the apex of the left ventricle. There was a replacement fibrosis at this point. Some parts were quite calcareous, and there was also slight interstitial myo carditis. The coronary artery was the seat of atheroma. Larkin (Med. Record. Aug. 2S, '97).
Case of multiple aneurism of pulmo nary artery in a boy, aged 12 years, in whom a loud, roaring, pulmonary sys tolic bruit and very highly-accentuated second sound were present during life. with lumnoptysis. epistaxis, and dropsy. Four of the secondary branches in one lung and three in the other led into aneurisms as large as walnuts, filled with blood-clot. The boy had been ill far a year. Churton (Brit. Med. Jour., May 15, '97).
case of hepatic aneurism in which the clinical picture included pains in the right hypochondrium or epigastrium, intermittent jaundice, and repeated, profuse Inemorrhages from the tipper part of the bowel. The diagnosis is
made but seldom. and cholelithiasis or duodenal ulcer is generally thought of. especially since all three symptoms do not always occur together. The most constant of these is the pain. In the pathogenesis trauma plays an important and rather often there is a history of sonic preceding infectious disease.
Sommer (Prager med. Woch., Sept. S. 10n2).
Prognosis.—Spontaneous recovery oc curs but seldom; a deposit of fibrin due to a slow current takes place in the sac and completely fills it, forming a firm and solid mass. The process may extend still further into the artery, thus ren dering the cure still more secure. The formation of an embolus is only to be expected, however, when the diseased artery is small. Spontaneous recovery may occur in other ways: from a clot being washed out of the sac into the artery, forming an embolus which com pletely arrests the current in the sac, the latter being filled with a firm coagulum.
The sac may also be heavy enough and so situated as to stop the current of the blood in the artery by causing flexion of the aneurismal neck.
In some cases inflammation of the sac and coagulation of the blood contained in it also effect a spontaneous cure.
Only small aneurisms are cured by spontaneous formation of a thrombus in the sac and its conversion into cicatricial tissue.
Death may result in various 1. By rupture of the sac. In this case death may occur instantly, if the opening be into a serous cavity, one of the pleural cavities (generally the left), or into the pericardial or peritoneal cavities, the serous membrane giving way in a rent.
Ten eases of sudden death due to rupt ure of thoracic aneurisms previously unsuspected. Deaths, although sudden, not instantaneous; sometimes consider able period may intervene. F. W. Draper (Boston Med. and Surg. Jour., Mar. 14, '95).
Cases of rupture of intrathoracie aortic aneurisms met with in the Pathological Department of the Manchester Royal Infirmary.