84 Handbuch der historisch-geographischen Pathologie, Band ii. p. 300.
Sex has a remarkable influence in securing immunity against hepatic abscess. According to the statistics of Rouis,85 of 258 cases of hepatic abscess, only 8 were in women. He rightly enough attributes this exemption rather to the difference in habits of the two sexes than to any merely sexual peculiarity. In 12 cases observed by the writer, only 1 was in a woman. In Waring's86 collection of 300 fatal cases of tropical dysentery, only 9 occurred in women. These facts are most conclusive regarding the relatively greater frequency of the affection in men. As might be expected, the age at which this disease occurs is the period of adult life, when exposure to the conditions developing it is most likely to happen. In general, then, hepatic abscess may be referred to the period mentioned by Rouis—from twelve to seventy-five years of age. In my own cases the youngest was eleven years and the oldest fifty-four years of age. It is not the broken-down subject of mature age or the weakling of youth who is attacked by hepatic abscess, but the more vigorous and able-bodied, who have, because of their strength and activity, been exposed to the manifold conditions producing it.
85 Recherches sur les Suppurations endémiques du Foie d'apres des Observations recueilles dans le Nord de l'Afrique, par J. L. Rouis, Paris, 1860, p. 189.
86 An Inquiry into the Statistics and Pathology of Some Points connected with Abscess of the Liver, by Ed. John Waring, Resident Surgeon of Travancore, 1854, p. iii.
Rouis finds that a combination of the lymphatic and nervous temperaments seems most favorable to the production of this malady. It is certain that those who have the bodily conditions influential in the formation of gall-stones are not unfrequently attacked by abscess. The passage of the calculi may induce a local peritonitis of considerable severity; their arrest in the duct, with the result of ulcerating through, producing peritonitis and adhesions, are conditions eventuating in the formation of an abscess always large and sometimes of enormous size. Under such circumstances the element of temperament has a secondary place in the aggregate of causes.
Not very often hepatic abscess results from external blows, contusions, and from penetrating wounds. The liver is so placed as to glide aside when a blow is inflicted on the right hypochondrium, and thus escapes direct compression. An injury which elsewhere would have but little effect may excite suppurative inflammation in the tropical—or, as it may be entitled, the hepatic—abscess zone. Climatic conditions, or the changed habits of Europeans in tropical and subtropical regions, exert a distinct influence in traumatic cases.
The most important causes of hepatic abscess exist in the state of the portal vein, hepatic artery, and the hepatic veins. In the valley of the Mississippi and its tributaries, where abscess of the liver is a comparatively common disease, it has been found that in a large proportion of the cases the initial stage is an affection of the rectum—a form of dysentery properly entitled proctitis. So far as this vast region is concerned, the intestinal disease which precedes abscess of the liver, and stands in a causative relation to it, is an affection of the mucous membrane from which the inferior hemorrhoidal veins arise. This disease, although having a dysenteric form, is not ordinary dysentery. The onset of the disease and its symptomatic expression are those of a mild affection of the mucous membrane of the rectum—so insignificant in some cases as to be recalled with difficulty. In tropical countries abscess of the liver may be associated with dysenteric ulcerations. This relation has been frequently observed, but is far from constant. In Waring's87 cases, which occurred in India, 31 per cent. of the fatal cases of hepatic abscess arose during the course of acute or chronic dysentery. De Castro of Alexandria88 finds that dysentery is the most frequent cause of abscess in that region, especially in the Greek hospital. Murchison89 considers tropical abscess of the liver as secondary to dysentery in a considerable proportion of the cases, but by no means in all. In non-tropical countries abscess of the liver is found to succeed to ulcerations of the stomach, the intestines, the bile-ducts, etc. In the case of ulceration of any part of the mucous membrane from which the portal vein receives branches a morbific material may be conveyed to the liver. This morbific material may be some unknown septic principle the presence of which in the liver will excite suppurative inflammation; it may consist of an embolus having septic power or a merely mechanical irritant; it may be micrococci or some other living organisms, which, arrested in the portal radicles, set up inflammatory foci, etc. There are many examples of hepatic abscess connected with dysenteric ulcerations of the intestine in which no embolus can be found. Admitting the presence of the embolus originally, its disappearance is readily understood by reference to the changes induced by suppuration. Excepting these cases there must be many in which no embolus can be found, because none existed; an unknown septic substance has excited the suppurative inflammation. Emboli may be lodged in the liver from thrombi formed in the peripheral distribution of the portal vein, or from distant parts of the systemic circulation, as in bone diseases. There has been no satisfactory explanation of the manner in which such emboli pass the pulmonary capillaries to be lodged in the liver. At one time there was supposed to be a special relation between injuries of the bones of the head and hepatic abscess, but it is now known that these cases are not more numerous than those due to osteo-myelitis in any situation. Abscesses in the lungs are greatly more frequent than in the liver in cases of this kind. According to Waldeyer,90 whilst in two-thirds of the cases of death from surgical diseases and injuries there were abscesses in the lungs, in only 6 per cent. were there abscesses of the liver. It is evident that the emboli entering the systemic circulation are usually arrested in the pulmonary capillaries. Klebs maintains that such emboli consist of parasitic organisms.
87 On Abscess of the Liver, supra.
88 Des Abcès du Foie des Pays chauds, et de leur Traitement chirurgical, par le Dr. S. V. Castro (d'Alexandrie d'Egypte).
89 Clinical Lectures, loc. cit., p. 178.