Besides the pathogenetic factors above mentioned, it may be well to refer in this connection to the effect of long-standing neoplasms. It has been found that amyloid disease is produced in some subjects by the cachexia resulting from the slow development and persistence of such a new formation. The special character of the neoplasm is of less importance in respect to this condition than the constitutional condition—the cachexia—induced by its slow growth and interference with nutrition. Although long-standing disease, especially of a suppurative kind, is known to be necessary to cause amyloid disease, Cohnheim144 has lately published some facts which seem to prove that the degeneration may occur more speedily than has been heretofore supposed. He has shown, contrary to the previously-accepted view, that amyloid degeneration may follow in three months after the reception of a gunshot wound. He records three cases in which the amyloid deposits ensued in six, five, and three months, respectively.
144 Virchow's Archiv, vol. liv. p. 271 et seq., "Zur Kentniss der Amyloidentartung."
According to the author's observation, a peculiar somatic type is either necessary to, or at least is greatly promotive of, the amyloid degeneration. If, for example, the same suppurative process occurs in a person of a blond and lymphatic type and in another of brunette and nervo-muscular type, the former will be much more likely to suffer from amyloid change than the latter. "The gelatinous progeny of albuminous parents" is the mode of expression used to designate this particular type.
PATHOLOGICAL ANATOMY.—To use the term amyloid liver is rather misleading, since this indicates the restriction of the morbid process to the liver, whereas it is perfectly well known to be rather widely distributed through various organs and tissues of the body. The term amyloid is itself confusing, since the albuminoid material so designated is not really starch-like. The corpora amylacea, so called, differ materially from starch-granules, and still more from the amyloid matter. According to Wagner,145 these substances "have nothing in common." In the study of the amyloid deposit it has not been possible to separate it from the tissue in which it is imbedded; hence the published analyses of this peculiar material are probably far from correct. However, it has been rendered probable that the amyloid deposit has close affinities with fibrin. One of the theories—that of Dickinson of London—assumes that this material is fibrin deprived of the potash associated intimately with it. According to Seegen, dystropodextrin, a material existing in normal blood, agrees with amyloid matter in its most essential characteristics. Although Dickinson's theory is not tenable, it has served a useful purpose in showing the close affinity of fibrin with this pathological product. What view soever may be entertained of its nature, it is certain that the material to which we apply the term amyloid is of albuminous origin. Under circumstances with which we are now unacquainted this material is deposited from the vessels, and, instead of undergoing organization and contributing to the structure of tissues, remains unorganized and unappropriated. It is known that this deposition of the amyloid material is related to the process of suppuration and to certain cachexiæ, but the intermediate steps remain unknown and inexplicable.
145 A Manual of General Pathology, by Prof. Dr. E. Wagner, p. 325 et seq.
The amyloid matter is first exuded into the coats of the finest ramifications of the hepatic artery, and therefore the first appearance of the disease is in the middle zone of the lobules. In this respect pathologists are agreed: that the amyloid deposits first appear in the walls of the vessels. Wagner maintained, in opposition to Virchow, that the exudation is limited to the vessels and does not extend to the hepatic cells, which perish by pressure and consequent atrophy. This point has not yet been decided. It seems most probable, however, that the ramifications of the hepatic artery and all the capillaries of the lobule are affected, and that the deposits in them lead to atrophic degeneration of the cells.
In consequence of this extensive implication of the vascular system of the liver important changes occur in the size, density, and appearance of the liver. The organ is greatly enlarged in all its diameters. When felt through the walls of the abdomen its outline is distinct, it is firm, even hard, to the sense of touch, and it projects from a finger's breadth to a hand's breadth below the margin of the ribs. The increase of size of the amyloid liver is very great, attaining in weight, on the average, twice that of the normal organ; but this size may be largely exceeded in exceptional instances. In respect to shape and outline the amyloid liver does not differ from the normal organ; for although its dimensions are increased, its relations to the parts adjacent are not altered. The weight of the amyloid liver may reach ten, twelve, even sixteen pounds avoirdupois. The color of the amyloid liver is very different from that of the normal organ: instead of having the reddish-brown tint, it becomes grayish, yellowish, or reddish-gray. In consistence the amyloid liver is firm and rather elastic and doughy, and on section the margins of the incision are well defined, even sharp. A very characteristic feature of the cut surface is its paleness, anæmia, or bloodlessness, and scarcely any blood is exuded, even from the large vessels. The appearance of the incised surface of the liver has been described by comparison with various substances: according to one, it is waxy; according to another, it is lardaceous. A thin section of a part of the liver far advanced in the amyloid change is distinctly translucent, almost transparent; but a marked difference is observable between the amyloid matter and the lobules proper, even in the cases of extreme deposit. The lobules are separated by an opaque yellow border, and the centre of each is marked by a spot of a similar yellow color.
The amyloid material is remarkable for its power to resist the action of chemical agents and putrefactive decomposition. The test originally proposed by Virchow—iodine—continues to be the most characteristic. Orth146 suggests a method of applying it which is very excellent in respect to the clearness with which the reaction is shown: A large, thin section of the affected liver is placed in a saucer of water containing some iodine, and after the reaction has taken place is laid on a white plate. Iodine tincture, diluted or the compound solution, is brushed over the affected region, when the amyloid matter assumes a deep mahogany tint and the normal tissues a merely yellowish hue. The distinctness of the reaction may be increased by brushing over the iodized surface some dilute sulphuric acid, when the amyloid matter takes a deep violet, almost black, color.
146 Diagnosis in Pathological Anatomy, Riverside Press, 1878, p. 321.
Only a part of the organ—namely, the smaller vessels—may be involved in the degeneration, and this may be restricted to patches or parts of the organ. With the amyloid change there may be associated syphilitic gummata, or the liver may be more or less advanced in fatty degeneration or in cirrhosis. Those parts of the organ not invaded by the disease are not often entirely normal; they are more or less darkened in color by venous congestion, distinctly softer, etc. The amyloid change is not limited to the liver, but extends to the kidneys, lymphatic glands, the intestinal mucous membrane, etc.