Volume 1

A dictionary of medicine : including general pathology, general therapeutics, hygiene, and the diseases peculiar to women and children / by various writers ; edited by Richard Quain.

Date:: 1882

Credit: A dictionary of medicine : including general pathology, general therapeutics, hygiene, and the diseases peculiar to women and children / by various writers ; edited by Richard Quain. Source: Wellcome Collection.

71/947 page 47

$in mechanical violence. Anything else which weakens the arterial wall, such as the exposure of the vessel in an abscess, is looked on as a cause of aneurism. The yielding of a weakened arterial wall is doubtless accelerated by irre- gularities of the circulation. The influence of syphilis and of intemperance in causing aneurism is widely believed, though perhaps as yet neither fact is absolutely established : the latter, at any rate, is rendered very probable from the consideration that chronic alcoholism tends to impair the nutrition of all the tissues, including the arteries, and is accompanied by a constantly irritable condition of the circulation. That syphilis may cause a fibroid degeneration of the vessels must also be allowed to be at least possible, and that it does so is the opinion of many eminent pathologists. If so, the tran- sition to aneurism is natural, if not inevitable. Another proved cause of aneurism is embolism, or the obstruction of a diseased artery by a fibrinous plug, which has been known to be followed by the dilatation of the artery immedi- ately above the plug, just as in very rare cases the ligature of a healthy vessel has given rise to the formation of aneurism above the tied part.' Violence is a very frequent cause of aneurism, ■even in cases which are not technically denomi- nated ' traumatic' The latter term is generally restricted to cases in which the vessel is wounded by a cut, or is known to be ruptured, and the aneurism makes its appearance at once ; and in these cases the aneurism is of the ' diffused' or ' consecutive' variety. But there are, no doubt, many cases in which the artery is partially torn, and the walls, being thus weakened, afterwards slowly yield at the injured spot. This fact is illustrated by the well-known experiment of Richerand, designed to explain the frequency of popliteal aneurism. The experiment consists in hyperextension of the knee in the dead subject. If this be carried on forcibly till the ligaments are heard to crack, it will usually be found that the two inner coats of the popliteal artery are torn. All these causes of aneurism act much more powerfully in later life than in childhood, and many are unknown in early years. Aneurism, therefore, is very rare in children. In cases where the arterial system is extensively affected with atheroma, a great number of aneurisms may be found in the same person, or another may form after the cure of the first. To such cases the term ' aneurismal diathesis' has been applied. This fact shows the great importance, in all cases of spontaneous aneurism, of examin- ing the whole body to detect disease of the heart or any second aneurism which may exist. Almost all aneurisms contain more or less clot, and much of this clot iff usually of the laminated variety, consisting almost entirely of fibrine mixed with more or less of the blood-corpuscles. Theso laminated coagula adhere very firmly to the interior of the sac; they aro arranged' con- centrically like the coats of an onion ; and usually lose their colour in proportion to their remote- ness from the blood which still circulates through the sac. Their deposition depends in a great ' For owes of this nnture bco System of Surgery, 2nd edit. »n\. Ul. p. 422. measure on the presence of rough projections from the wall or mouth of the sac, and on the shape of the aneurism. When the latter is purely cylindrical, much less coagulum, poss'ibly none, will be found in it. When the tumour stands well away from the artery, so that the force of the circulation is much broken, the formation of coagula is greatly favoured. The deposition of such firm coagula must be looked on as the commencement of spontaneous cure, and at any rate defends the patient from the risks of rupture, or of renewed growth of the tumour at the parts which are so lined. Symptoms.—The symptoms of arterial aneu- rism are as follows:—There is a pulsating tumour, which is situated in the course of one oi the arteries, and which cannot be drawn away from the vessel. The pulsation is equable and ex- pansile, that is, it not only causes an up-and-down movement of the tumour, for such a movement may be communicated to any tumour by a large vessel lying in contact with it, but also expands the tumour laterally and in all other directions. The pulsation is in most cases accompanied by a bruit or blowing sound, heard on auscultation, which can be tolerably well imitated by the lips, and which is synchronous with the pulsation. Pres- sure on the artery above suspends both the pulsation and the bruit. Sometimes it may be noticed that the pulse below is retarded, that is, that it reaches the finger later than in the corresponding vessel on the other side. Besides these, which are the main signs of aneurism, there are others, which are of less constant occurrence or of subordinate impor- tance. Thus, on compression of the artery above, the tumour will empty itself more or less com- pletely, and the greater or less change of size under these conditions is a useful test of the proportion of fluid and solid in the sac. Some- times pressure on the artery beyond the tumour may cause an increase in its size. The pulse below the tumour is often found to differ strik- ingly from that on the sound side. There are many and various symptoms due to the pressure of the aneurism on neighbouring veins, nerves, bones, and viscera—symptoms which are of subordinate importance in a diagnostic point of view in the case of external aneurism, but are often of the greatest value in thoracic and abdominal aneurisms. Thus dyspnoea and ring- ing cough from pressure on the trachea, spasm or paralysis of the vocal cords from pressure on the recurrent laryngeal nerve, pain in the back from pressure on the vertebrae, or neuralgic pains from pressure on the nerves at the root of the neck, are well-known symptoms of aortic aneu rism; and, similarly, pain in the leg from pres- sure on the popliteal nerve, and oedema from com- pression of the vein are frequent symptoms of popliteal aneurism. Diagnosis.—The affections which are usually confounded with anourism are tumours of various kinds lying upon arteries, abscesses, and can- cerous tumours which have large vascular spaces in their interior, and therefore pulsate. The tumours which receive pulsation from arteries against which they lie are of various kinds; cysts and enlarged glands in the popliteal space] and enlargements of the thyroid body pressing$