Indulgence in the starchy and saccharine foods plays a part in the formation of gall-stones not less, if not more, important than the consumption of fats. A diet of such materials is highly fattening, and if the necessary local conditions exist they readily undergo fermentation, and thus cause or keep up a catarrh of the mucous membrane.
Too long intervals between meals, Frerichs165 thinks, is more influential than errors of diet in causing concretions. The bile accumulates in the gall-bladder, and the condition of repose favors the occurrence of those changes which induce the separation and crystallization of cholesterin. Obstacles to outflow of every kind have the same effect. The largest calculus in my possession was obtained from a case of cancer of the gall-bladder which compressed, and finally closed, the cystic duct. Sedentary habits have the same mechanical effect, but, as already pointed out, insufficient air and exercise act by lessening oxidation. Corpulent persons indulging in rich food and avoiding all physical exertion, those of such habits confined to bed by illness or injury, the literary, the well-to-do, self-indulgent, lazy, are usual subjects of this malady. Any condition of things which causes a considerable retardation in the outflow of bile will have a pathogenetic importance, especially if the causes of chemical change, the lessened quantity of taurocholic and glycocholic acid, and an increased quantity of cholesterin, coexist. Moral causes, as fear, anxiety, chagrin, anger, etc., have seemed to exercise a causative influence in some instances (Cyr).
165 A Clinical Treatise on Disease of the Liver, Syd. Soc. ed., vol. ii. p. 511.
To the causes of retardation of the bile-flow mentioned above must be added catarrh of the bile-ducts. This acts in a twofold way—as an obstruction; a plug of mucus forming the nucleus. It has already been shown that fermentative changes may be set up by the mucus, which plays the part of a ferment, an acid state of the bile resulting.
Situation of Gall-stones, and their Destiny.—The gall-bladder is, of course, the chief site for these bodies, but biliary concretions and masses of inspissated bile may be found at any point in the course of the ducts. Single stones may be impacted at any point in the cystic, hepatic, or common duct, or masses composed of numerous small calculi may take the form of a duct and branches, making a branching calculus of the shape and size of the mould in which it is cast. Such casts may be hollow, thus permitting an outlet to the bile, or they may completely close the tube, and a cyst form, the walls of which grow thicker with connective-tissue deposits. Stones of very large size may be thus enclosed, Frerichs having seen one the size of a hen's egg formed about a plum-seed, which was the nucleus. In some rare instances the major part of the larger tubes have been filled with inspissated bile, through which the fluid bile could only be slowly filtered.
Calculi are not often found in the hepatic duct, since they can only lodge there in descending from the smaller tubes, and hence are too small to become wedged in. The usual site, as has been sufficiently explained, is the gall-bladder. At the entrance to the cystic duct and at the terminus of the common duct in the duodenum are the points where migrating calculi are most apt to be arrested.
Spontaneous disintegration of gall-stones sometimes occurs. Cholesterin being dissolved off of the corners and edges, the cohesion of the mass is impaired and it falls apart in several fragments. By very slight mechanical injury air-dried calculi will be broken up. In the gall-bladder two factors are in operation to effect the disintegration of the contained calculi: the movements of the body, by which the corners and the borders are crumbled; the solvent action of the alkaline bile on the cholesterin. When, however, these concretions are made up of lime and pigment, their integrity can be impaired only by the process of cleavage; no solvent action can take place.
Various changes occur in the ducts or in the gall-bladder in consequence of the presence of these concretions. Whilst a catarrhal state of the mucous membrane of the ducts is an element of much importance in the process by which concretions are formed, on the other hand the presence of these bodies excites catarrh, ulceration, perforation, and, it may be, abscess of the liver. When concretions form or are deposited in the ducts, they cause inflammatory reaction, the walls yield, and the neighboring hepatic structures may also be affected by contiguity. The dilatation of the tube is usually cylindrical, much more rarely sacciform. The neighboring connective tissue may undergo hyperplasia and a more or less extensive sclerosis occur. More frequently the calculus ulcerates through, and an abscess is produced which will take the usual course of that malady. Very rarely a calculus is found enclosed in a separate sac and surrounded by healthy hepatic tissue (Roller).166
166 Berliner klin. Wochensch., No. 42, 1879; ibid., Nos. 16, 17, and 19 for 1877, Fargstein.
As the gall-bladder is the usual place for the formation and storage of gall-stones, the changes in connection with this organ are the most important. The calculi may be so numerous or so large as to distend the gall-bladder and cause it to project from under the inferior border of the liver, so as to be felt by palpation of the abdominal wall. The stones may be few in number and float in healthy bile, or they may fill the bladder to the exclusion of fluid, the cystic duct being closed permanently; or there may be, with one or more concretions, a fluid composed of mucus, muco-pus, serum, and bilious matter. The mucous membrane may be in a normal state, but this is rare; usually it is affected by the catarrhal process, and atrophic degeneration has taken place to a less or greater extent; the rugæ are obliterated, the muscular layer hypertrophied. When attacks of hepatic colic have occurred, more or less inflammation of the peritoneal layer of the gall-bladder and cystic duct is lighted up, and organized exudations form, changing the shape and position of the organs concerned. It is usual in old cases of hepatic colic to find the gall-bladder bound down by strong adhesions, the cavity much contracted or even obliterated, the cystic duct closed, and the neighboring portion of the liver the seat of sclerosis. Such inflammatory exudations about the gall-bladder may become the seat of malignant disease—of scirrhus. Several examples of this have been reported, and one has occurred in my own practice.