4 Duguet, p. 10, etc.
5 Untersuchungen über die Embolischen processe, 1872.
6 Zeitschrift für klinisch Medicin, Erster Band, 131.
ETIOLOGY.—Predisposing Causes.—The male sex affords predominance of cases, because of greater liability to accidents, to the various forms of ulcerative destruction of lung-tissue, and to aneurisms of the aorta and pulmonary artery.
The adult age is most exposed for similar reasons. Ogston's statistics7 support in a general way, but not with strictly technical force, their quotation by Herz.8 Omitting the last 4 of his 20 cases (2 of which were from poisoning, 1 from fracture of skull by a fall down stairs, and 1 from drowning), the average for males (12) was 56.4, and 55.3 for females (4).
7 Brit. and For. Med.-Chir. Rev., vol. xxxvii., 1866, p. 459.
8 Ziemssen's Handbook, vol. v. p. 298. Ogston says (p. 465) it did not appear, however, that any distinct rent of their substance had taken place—to any extent, at least. "When we consider that the area of the extravasation was sufficient to involve often one or two entire lobes, and that death was in most of them very sudden, the cases may be adopted as showing the action of causes similar in kind, if not in degree, to those operative in undoubted pulmonary apoplexy."
As more efficient predisposing causes than either age or sex, may be mentioned aneurisms of the aorta and pulmonary artery, amyloid degeneration of bronchial and pulmonary vessels, the influence of Bright's disease in producing disease of blood-vessels, and atheromatous diseases of the pulmonary artery.
Exciting Causes.—Penetrating and contused wounds of the chest by their direct mechanical effect, and diseases and injuries of the brain through the medium of the nervous system, may produce pulmonary apoplexy, the result in the latter case being usually an infiltration or small infarction.
SYMPTOMATOLOGY.—Pulmonary apoplexy is the least common of the two forms of distinctive pulmonary hemorrhage, the other being pulmonary infarction, already treated of under [HÆMOPTYSIS]. A proportion of cases is associated with mitral disease in its most advanced stages. At that time we may expect pneumorrhagia, but whether from infarction or apoplectic laceration even the event can only occasionally determine. In the latter, if hemorrhage makes its appearance it will be copious and generally overwhelming; at other times the hemorrhage may not appear, and the patient dies suddenly with possibly other indications of the internal flow. The physical signs cannot be relied on, for often the pulmonary tissue is already changed by the long-continued obstruction of circulation. Rupture of aneurism, particularly of aorta, in the great majority of cases takes place into a bronchus, and not into the parenchyma. In case of wounds of the contused variety a laceration of parenchyma occurs at times sufficient to produce marked hæmoptysis. If the blood be not ejected, there are no certain indications of what has happened. If the case be seen immediately after the accident, such physical signs as moist bubbling râles on the margin of an area of feeble or suppressed vesicular murmur, possibly attended with a dull, high-pitched percussion note over that area, would afford a strong presumption in favor of ruptured lung and consequent hemorrhage.