Definition.—An aneurism is a circumscribed dilatation of an artery, formed by the giving away of one or more of its coats, and may be sacculated, fusiform, or cylindrical in form. Several forms or types are recognized.
(a) The true aneurism is where the sac is formed of one or more of its coats.
(b) The false aneurism is where there is a rupture of the coats, and the blood is found in the adjacent tissues.
(c) A dissecting aneurism is where there is a rupture of the intima, and the blood burrows, or dissects, between the walls of the vessel. The aorta is the usual seat, and may be traversed its entire length.
(d) A miliary aneurism, so named from its minute size, is found in the cerebral vessels.
(e) An arterio-venous aneurism is where the dilatation occurs in veins, the result of a communication being established with an artery.
These various forms are termed axial, when the entire circumference of the vessel is involved in the dilatation, and peripheral when the dilatation involves but one side of the artery.
Etiology.—Age and sex are predisposing factors, the disease occurring between the ages of thirty and fifty, and mostly in men. An enfeebled condition of the walls of an artery is necessary for the development of an aneurism. This may be congenital or it may be acquired. The most frequent cause is arteriosclerosis, especially during the early stage, before compensatory changes have taken place.
Syphilis, gout, rheumatism, alcoholism, lead poisoning, uric acid, Bright's disease, and diabetes, are conditions that enfeeble all tissues, the arterial coats not excepted.
Severe exertion or strain is also responsible for a weakening of the vascular walls, and how much is due to strain, and how much is due to syphilis, in soldiers and sailors, is difficult to state, though each figures quite extensively.
Traumatism should be considered as an etiological factor, and heavy body bruises or blows upon the chest would tend to weaken vascular walls.
Embolism.—The plugging of an artery by an embolus is apt to result in the development of an aneurism on the proximate side of the obstruction.
Mycotic Aneurism.—More recent examinations tend to show that, in some cases, the weakened condition of the walls is due to micro-organisms; at least an abundant product of micro-organisms have been found present in the aneurismal sac.
Pathology.—There is generally degeneration of the arterial walls, arterio-sclerosis being frequently present. In some the intima and media have been destroyed, the adventitia being the retaining wall. The blood in an aneurismal sac may become laminated and of a fibrous character, thus restoring the arterial wall. There is generally hypertrophy of the heart due to arteriosclerosis.
Aneurism of the Thoracic Aorta.—Of over nine hundred cases of aneurism collected by Crisp, forty-five per cent were found in the thoracic portion of the aorta, and eleven per cent in the abdominal aorta, or about seventy-five per cent of all aortic aneurisms were located in the thoracic portion, over fifty per cent being found in the ascending portion, and diminishing in frequency as the distance from the heart increases.
Symptoms.—The symptoms depend largely upon the size and location of the aneurism. If small, the disturbance is so slight that it is not recognized; but as it increases in size and interferes by pressure, characteristic and distressing symptoms make their appearance. Should the aneurism be located where there is plenty of room for development without pressing upon important parts, it may attain a large size without local or systemic disturbance. Since location determines the symptoms, we will consider them according to the part affected.
(1) Aneurisms of the Ascending Portion of the Arch.—If the aneurisms are small and near the sinuses of Valsalva, they may remain unsuspected till a sudden termination of life reveals a ruptured aneurism in the pericardium.
When located above the sinuses, earlier and more pronounced symptoms are present. Thus, if the aneurism be located on the right or convex border, the pressure would be against the superior venae cavae, which would result in congestion and edema of the upper extremities, or the pressure may involve only the sub-clavian, resulting in enlargement and edema of the right arm.
They may attain very great size, pushing out into the pleura or forward against the sternum and ribs, causing erosion, and finally appearing beneath the skin as pulsating, bluish tumors. They may press against the right recurrent laryngeal nerve, which will be followed by dyspnea and apnea.
Should the aneurism be located on the left or concave border, the pressure would cause displacement of the heart, forward, downward, and to the left. Pressure on the inferior venae cavse would cause dropsy of the lower extremities.
Death is usually sudden, the warning symptoms being intense pain, cyanosis, and dyspnea. It may rupture into the pleura, pericardium, superior venae cavae, or externally, according to location.
(2) Aneurism of the Transverse Portion of the Arch.—The most pronounced symptoms occur when developed in the transverse portion, owing to the small amount of space afforded for their development, and consequently they exert greater pressure upon neighboring parts.
It may extend in the usual direction, backward, and press in against the trachea, causing a ringing, paroxysmal, metallic cough, with more or less dyspnea, or, pressing against the esophagus. cause difficulty in swallowing. The tumor may press against the bronchi, which embarrasses respiration, and is attended by severe attacks of paroxysmal coughing, with watery or muco-purulent expectoration. Marked dilatation of the bronchi may follow. When very large, the tumor may press against the lung, giving rise to severe pulmonary symptoms, and, in time, to suppuration, termed by Osier, aneurismal phthisis.
The left recurrent laryngeal may be affected with the same result as where the right was involved; viz., cough, dyspnea, and aphonia. The aneurism may encroach upwards, involving the carotid and subclavian on the left side, or the carotid and innominate on the right. The sympathetic may be involved by pressure, resulting in dilatation of the pupil where the irritation is slight; but where more severe, paralysis may follow, with the contracted pupils. Where the thoracic duct feels the encroaching tumor, general atrophy follows.
When the aneurism develops on the anterior portion of the arch, it encroaches upon the sternum, and by continued pressure may cause severe erosions. The aneurism may develop to an enormous size, encroaching upon both the right and left pleura, crowding both the lungs.
(3) Aneurism of the Descending Portion of the Arch.—The pressure is mostly backward against the vertebrae, extending from the third to the sixth dorsal, oftentimes causing erosions. It may make its way to the scapula, and project as a pulsating tumor. There is sometimes compression of the cord, which is attended by great suffering. The esophagus and bronchi may be pressed against, with dysphagia and bronchiectasis, to which reference has already been made.
The descending portion of the thoracic duct is generally involved near the diaphragm, the tumor lying against the lower dorsal, which may be severely eroded.
Wherever located, pain is always a distressing and prominent symptom. If the. aneurism is of sudden development, as sometimes occurs under great physical exertion, the patient experiences a sudden "giving way," due to rupture of the tunica media, and attended by a sharp pain in the upper part of the chest.
The pain in later stages may be the result of stretching of the nerve filaments in the Walls of the aorta, or it may be due to pressure upon the adjacent parts. Where there is erosion of the bone, as of the sternum or vertebras, the pain is of a boring character, and causes great suffering. In rare cases the tumor may develop to great size, with but very little pain, even where there has been erosion of the bone.
Physical-Signs.—The physical signs, like the general symptoms, depend upon the size and location of the tumor; if small and deep-seated, a physical examination may fail to reveal the tumor.
Inspection.—One of the most important and characteristic signs is a pulsating tumor of the chest, and, though there may be no protrusion of the walls of the chest in the early stage, by standing at the patient's side, and having the light strike him obliquely, a pulsation synchronous with the systols of the heart may be revealed.
If the aneurism be of the ascending arch, the pulsation will be to the right of the sternum and in the second or third interspace. If located in the transverse portion, the sac will be behind the manubrium, though it may be seen pulsating at the supra-sternal notch. Where the innominate artery is the seat .of the aneurism, the pulsation will be seen above the second rib extending into the neck.
If the descending portion be involved, the pulsating tumor will be seen to the left of the spinal column, extending into the scapular region.
In some cases there is marked bulging of the tumor, caused by erosion of the sternum or ribs or perforation of the back. They vary in size from a billiard-ball to a cocoanut. The skin covering the tumor is thin, smooth, and stained a dark-red color. If the aneurism be large, the apex-beat will be displaced downwards and to the left.
When there is compression of the superior cava, there will be cyanosis of the head, upper chest, and arms. Where there is compression of the inferior cava, the abdominal walls and legs will be congested and dropsical.
Palpation.—When inspection fails to reveal pulsation, the tumor is deep-seated, and may be recognized by palpation. By placing one hand over the sternum and the other over the spine, a strong, heaving pulsation is imparted to the hand, radiating in every direction, and known as the expansile pulsation. When the tumor has perforated the chest, and the hand can grasp the tumor, this expansile character is much more marked.
One of the signs of great value in aneurisms is the diastolic shock imparted to the hand on palpation, and is synchronous with the closure of the aortic valves. This usually occurs when the aneurism is at the root of the aorta. Where there is dilatation of the arch, a systolic thrill is sometimes present.
Percussion.—Where the aneurism is deep-seated, percussion will most likely give negative results; when the tumor reaches the chest-wall, however, an abnormal area of dullness is heard, the location depending upon the part affected: thus, if the aneurism be located in the ascending portion of the arch, the dullness will be to the right of the sternum and above the third rib. If situated on the transverse portion, the dullness will be over the sternum and to the left; while if on the descending portion, it will be heard in the left interscapular region. The sound is peculiarly flat.
Auscultation.—Auscultation may reveal murmurs that are characteristic, or give negative results, depending upon the thickness of the laminae of fibrin. The most characteristic sign is a systolic murmur heard over the area of dullness, and transmitted to the carotids, and if there be aortic insufficiency a diastolic murmur will also be heard. In large aneurisms of the arch a loud, ringing, accentuated second sound is a sign of diagnostic value.
Drummond speaks of a systolic murmur heard in the trachea, due to the expulsion of air at each distention of the sac.
A physical sign of importance is a slowing of the pulse in the arteries beyond the aneurism, the sac acting as a reservoir, breaking the force of the systole. When the sac is very large, there will be an absence of pulsation in the abdominal and femoral arteries from the same cause.
The two radial pulses may show a marked difference in time; thus, if the aneurism be situated in the transverse portion of the arch and the innominate is not involved, the pulse at the right wrist and in the neck is strong and almost synchronous with the systole of the heart, while the pulse of the left wrist is small, weak, and retarded.
Surgeon-Major Oliver described what at one time was regarded as a very valuable sign, a tracheal tugging. The patient is directed to sit or stand in an upright position, close the mouth, and elevate the chin. The cervical cartilage is then grasped between the finger and thumb and elevated till the trachea is tense, when there will be a downward dragging or tugging at each systole. When taken with other signs it is valuable: but alone, it will not be of much weight, as it is sometimes found in health and in other diseases
Diagnosis.—The diagnosis of an aneurism is sometimes quite difficult, if not impossible. In some cases the symptoms are so obscure and the aneurism so deep-seated that, after the most careful examination, the lesion may not be discovered. This is especially true if the aneurism be small and located in the sinuses of Valsalva.
If the patient's occupation has required great physical exertion, and his age is between thirty and forty-five, and should there be a history of arterio-sclerosis coupled with obscure thoracic pains, sudden attacks of intense pain and anginoid in character, or pain radiating along the bronchial plexus or intercostal nerves, we would think of aneurism.
If to these symptoms are added dyspnea, dysphagia, aphonia, and cough, either of a dry, ringing, metallic character—laryngeal, or loud, and hoarse,—bronchial, with profuse expectoration; or if there be edema and congestion of the upper extremities, and if a physical examination reveals dullness in the aortic region, a systolic murmur, and a systolic and diastolic accentuation of the second sound, change in the character and time of the pulse, and the marked difference between the left and the right pulse, and if to all these symptoms be added, the tracheal lugging, the diagnosis is assured.
A differential diagnosis has to be made between aneurisms and solid tumors, pulsating empyemia, pulmonary tuberculosis, and abnormal pulsations of the aorta. The tumors that are most likely to be confused with aneurisms, are cancers, sarcomas, and glandular enlargements of the mediastinum.
If we bear in mind, however, that while tumors and enlarged glands may give rise to all the pressure symptoms of aneurisms, abdominal pulsation is either lacking, or, if present, is quick, not slow and expansive.
There is also an absence in growths, of the systolic thrill on palpation, and the diastolic shock is missing. On auscultation, if there be a tumor, the systolic murmur is either absent or very faint, and accentuation of the second sound is not perceptible. There is also uniformity in the radials, and tracheal tugging is not present. If the growths be malignant in character, or a sarcoma, there will be greater evidence of malnutrition, more emaciation, and that peculiar appearance designated as cancerous cachexia. The pain is more constant, and there is enlargement of the axillary and cervical lymphatics.
Pulsating Empyema is not so circumscribed, but covers a more superficial area, is not expansile, and is produced by respiratory movement.
Auscultation fails to reveal the characteristic murmur or diastolic shock and there is no retardation of the radial pulse. On the other hand, chills, hectic fever, night-sweats, and emaciation, characteristic symptoms of empyemia, render the case a plain one.
Pulmonary Tuberculosis.—Where an aneurism presses a bronchus, causing dilatation, attended by cough and profuse expectoration, followed by fever and emaciation, the symptoms may be -mistaken for phthisis; in the latter, however, the history, the night-sweats, greater fever, and emaciation, will enable us to distinguish the one from the other.
Abnormal Pulsation in the Aorta.—We meet with abnormal pulsation in neurotic patients, generally females, and occasionally in retraction of the lungs.
Curvature of the spine may give rise to displacement of the aorta, with forcible pulsation. When these conditions are present, there is one marked difference from aneurisms; namely, absence of retardation of the pulse and the characteristic expansile pulsation. The perfecting of the use of the X-ray will most likely render the diagnosis of aneurism positive.
Prognosis.—The outlook in thoracic aneurism is always serious, and though recovery may take place spontaneously, and by treatment, the tendency is towards a fatal termination, and recoveries are very rare.
Rupture and sudden death may occur at any moment. According to Lebert, who examined a large number of cases, the duration of life, from the time the first distinct symptom made its appearance until death, was from fifteen to eighteen months. The patient's occupation and habits will determine to a certain extent the length of life. Where an even, quiet life is led, the patient may live for years.
Treatment.—To effect a cure we must resort to such measures as will promote coagulation of the blood and bring about contraction of the sac, and any treatment that favors this condition will be highly beneficial.
To accomplish this, the late Dr. Tufnell, of Dublin, advocated rest in bed and a dry diet. By these means the fluids in the system are reduced to the minimum, arterial tension is lessened, the amount of fibrin increased, and the number of heart-beats greatly lessened. Tufnell's diet list was very rigid and consisted of the following bill of fare: For breakfast, two ounces of bread and butter and two ounces of milk; for dinner, two or three ounces of meat and two ounces of milk or claret; for supper, two ounces of bread and two ounces of milk.
There is no doubt that rest in bed and the above rigid diet would greatly lessen the number of heart-beats and lessen the quantity of fluids in the body, but there are few patients who would submit to such a quiet life and so rigorous a diet; indeed it is not necessary to go to quite such extremes, though the patient must lead a quiet life, and his fluids should be restricted.
Tea, coffee, and alcohol should be forbidden, and his allowance of water reduced to eight or ten ounces per day.
To produce coagulation of the blood, the introduction of fine wire, horsehair, or fine catgut has been practiced with some degree of success. Galvano-puncture, electrolysis, and the injection of styptics have been used for the same purpose. There is always some danger, however, attending these local measures, since coagulated particles may float off and give rise to embolism. Ergotine dissolved in water or glycerin has been injected directly into the sac, in the hopes of inducing contraction in the smooth muscles of the walls of the aneurism.
Iodide of potassium has been largely used by the old school as a remedy for aneurism.
The pain, when very severe, will call for morphia. The calcium salts are thought to influence the process of clotting, and may be used, though too much reliance must not be placed in their efficacy. The natural mineral waters may be freely used to prevent constipation.