Number and proportion of cases: Among the last 4593 cases submitted to pathological examination rupture of a thoracic aneurism has been noted in 32 cases. This gives a percentage in all "general" cases of 0.69.
Sex: Of the 32 eases, 30 were men and only 2 women; that is, a percentage of 93.75 males and 6.25 females.
Age: The exact age was obtained in 30 of the cases; the others were middle aged males. The average was 40 years. The males averaged 40.4 years. The females averaged 34 years. The young est subject was aged 20 years and the oldest was aged 65 years.
Seat of aneurism: In many instances the greater part of the arch was involved. Grouped, however, according to the chief area of affection, they may be arranged as follows: Ascending portion of arch, 12; transverse portion of arch, 11; descending portion of arch, 4; and descending thoracic aorta, 5.
Point of rupture: This can be best indicated in tabular form:— Nature of death: Of the thirty-two eases, six were observed in medico-legal investigations, the subjects being brought dead to the hospital, having been found dead or suddenly seized in the street or elsewhere. In one instance a man, while riding in a cart, suddenly fell out of the vehicle and was picked up dead. In nearly all the cases where rupture oc curred while in hospital or where a clear history could be obtained death was sudden, in many instances being practically instantaneous. In one case, where rupture occurred into the (esoph agus, death took place in five minutes. In another, where the aneurism burst into the pericardium, the patient felt faint and was dead in three minutes. In one subject, where the pericardium was found filled with blood, and where there was commencing erosion into the trachea, with also extension into the left lung, a small quantity of frothy blood was brought up for some hours before death, which was sudden. In a case where there was general aneurisinal dila tation of the arch of the aorta, rupture took place into the pericardium through a vertical slit two and a third inches in length. The patient was brought to the hospital in what appeared to be a syncopal attack, and died suddenly four hours later. In one case where death occurred suddenly, blood-clot weighing eighty-five ounces was found in the left pleural cavity. T. N. Kelynack (Lancet, July 24, '97).
Death is not so rapid when the aneu rism reaches to the skin or to a mucous membrane, such as the trachea, oesopha gus, intestine, or bladder.
The rupture of an aneurism through a mucous surface occurs by the forma tion of a small, circular abscess; through a serous surface the rupture is by a fis sured or star-like opening. In the skin a small slough is formed, which, on fall ing, leaves a minute opening, through which the blood passes. This is soon arrested by clotting, but the hcemor rhage soon recurs and death is finally caused by repeated hmmorrhages.
2. Death may occur from the compres sion of important organs. Pressure upon the trachea, bronchi, or lungs causes suf focation; upon the oesophagus or tho racic duct inanition.
In tubular aneurisms death may be ' caused by syncope due to impediment to the circulation or by compression of the oesophagus or bronchi or by rupture into the pericardium.
When the vertebrw and ribs are com pressed these bones are absorbed and spinal irritation and even meningitis are produced. Pressure upon the intercostal nerves gives rise to severe neuralgia.
3. Inflammation and suppuration of the sac may cause death by inducing septimmia and pymnia.
4. If the aneurism is in the arch of the aorta a clot may be carried to the brain by the cerebral arteries, causing embolism and death.
5. Gangrene of an extremity caused by obstruction may cause death by septic infection.
A sacculated aneurism usually forms upon a tubular aneurism and causes death more rapidly than the tubular aneurism alone would have done.
Duration of Aneurism.— Though an aneurism may grow very rapidly, it lasts several years, in the majority of cases. So long as the cause is present it tends to develop.
The various causes which influence the duration of an aneurism are its situ ation, the size of the mouth of the sac, the condition of the latter, the force of the blood-current, the state of the blood as to coagulation, and the mode of life of the patient.
Treatment of Aneurisms in General.— Obliteration of the sac and occlusion of the afferent and efferent vessels are the aims to be reached.
The best results may frequently be ob tained by combining several modes of treatment.
Obliteration of the sae can be obtained by diminishing the force of the circula tion of the blood in it, thus encouraging coagulation.