CAUSES.—Catarrh of the bile-ducts has been referred to all those causes which can excite a catarrhal process in any situation. These are systemic and local. Amongst the systemic may be placed peculiarities of constitution or idiosyncrasy. A tendency to hepatic disorders is a feature in certain types of constitution, and, as such types are transmitted, the hepatic disorders seem to be inherited. In such persons, possessing the so-called bilious nature, catarrh of the biliary passages is not uncommon, and a special susceptibility to it apparently exists. The atmospherical and other causes which in some subjects will set up a catarrh of the bronchi will in the bilious type induce a catarrh of the duodenum and bile-ducts. The malady is not inherited; only the character of bodily structure which favors it under the necessary conditions.
Climatic changes and certain seasons, especially the autumn, are influential causes. Exposure to cold and dampness, the body warm and perspiring, will set up a catarrhal process in the bile-ducts and intestine, especially in those having the special susceptibility which belongs to certain bodily types. Malarial miasm is an especially active cause in malarial regions. The writer has seen many examples in various parts of the United States within the malaria-breeding zone. Other miasmatic agencies are not without importance. The exhalations from the freshly-upturned soil of some cities, the gases from cesspools and sewers, and illuminating gas exert a causative influence. The bad air thus made up has been happily called civic malaria.
The most influential causes of catarrh of the biliary passages are local in origin and in action: they are the agencies which induce catarrh of the duodenum. Disturbances of the portal circulation should be first named. Whenever obstructive lesions of the cardiac orifices exist, whenever the pulmonary circulation is impeded by disease of the lungs, the portal vein is kept abnormally full, and as a necessary result of the stasis a catarrh of the mucous membrane follows. Congestion of the portal system may be a result of vaso-motor paresis. The abdominal sympathetic may be the seat of various reflex disturbances: those of a depressing kind induce stasis in the portal system. Certain medicinal agents have this effect, and prolonged and severe cutaneous irritation, it is probable, may act on the portal circulation in the same way. The action of cold on the peripheral nerves may be similarly explained.
Catarrh by contiguity of tissue is the most frequent factor. Catarrh of the duodenal mucous membrane is the initial condition, and from thence the process extends to the bile-ducts. Although the duodenum may be alone affected, the usual state of things is a gastro-intestinal catarrh, the stomach and the whole length of the small intestine being simultaneously diseased. When the catarrhal process is thus diffused the duodenal mucous membrane is most deranged, probably because the acid and fermenting chyme is first received here, and what acridity soever it may possess attacks this part in its greatest strength. It must be remembered that the secretion of the duodenal glands and of the pancreas and liver must also have an abnormal character; hence those foods which in the healthy condition of things are digested in this part of the canal undergo ordinary putrefactive decomposition and furnish very irritating products. This observation is especially true of the fats: the fat acids are in the highest degree irritating. The digestive fluid of the duodenum has a more or less pathological character, because the catarrhal process not only interferes with the habitually easy flow of the gland secretions, but, extending to the gland elements themselves, gradually alter their structure.
Gastro-intestinal catarrh results from the misuse of foods and the abuse of certain condiments and of spirits. Excess in the quantity of starchy, saccharine, and fatty foods which undergo conversion and absorption in the intestine, habitually consumed, decomposition of such portions as escape proper digestion ensues, and the products of this decomposition exercise an irritant influence on the mucous membrane. The daily consumption of sauces and condiments and of highly-seasoned foods has a constant irritating action; but more influential than any other causative agency is the abuse of malt liquors and spirit. Whilst the latter acts more on the stomach and the liver proper, the former affect more the duodenal mucous membrane and the bile-ducts.
To these causative agencies must be added a pathological state of the bile itself. Under conditions not now known the bile seems to acquire acrid properties and set up a catarrh in passing along the ducts.
PATHOLOGICAL ANATOMY.—The area affected by the catarrhal process varies greatly. The termination of the common duct for a short space may be the only part affected, but with this there is always more or less, sometimes most extensive and severe, duodenal catarrh, followed by jaundice. The extent to which the common duct is affected may be exactly indicated by the staining with bile, which extends down to the point of obstruction. The catarrhal process may invade the whole extent of the common duct, the cystic duct, gall-bladder, and the ramifications of the tube throughout the organ. The resulting appearances will vary accordingly.
The first change observable is a more or less considerable hyperæmia of the mucous membrane; but this is rarely seen, because the examination cannot be made at the time when this condition is present. The epithelial layer is swollen, sodden, the cells cloudy, undergoing rapid multiplication and desquamating. The cast-off cylindrical epithelium, mucous cells, and serum make up a turbid mixture, which, with bile, fills the smaller ducts, and may in places, especially at the orifice of the common duct, form an obstruction sufficient to prevent the passage of the bile; which may, however, be readily pressed out with a little force. Especially near the end of the common duct the mucus is apt to accumulate, and a plug of it, often tenacious and somewhat consistent, obstructs the orifice. It is probable that whilst catarrh is the chief cause of jaundice, it may also, by a merely intermittent activity, cause the condition of biliousness—now so far relieved as to permit the bile to descend into the intestine, now so much obstruction as to prevent the escape of any considerable part of that formed. When the common duct is the seat of the catarrhal process, and the outflow of bile thus prevented, it accumulates in the gall-bladder, which may be so far distended as to present a recognizable tumor of pyriform shape through the abdominal parietes.
When the catarrhal process invades the finer ducts the appearances are somewhat different. There are no bile-stains along the course of the common and cystic ducts, and the gall-bladder is empty, or at most contains only some mucus, with altered bile. The tubes at or near their ultimate ramifications contain a turbid mucus composed of cylindrical epithelium and lymphoid cells, and tenacious enough to close them firmly. More or less hyperæmia of the liver-structures proper, and consequent increased dimensions of the organ, a more or less active catarrhal condition of the duodenal mucous membrane, accompany the changes in the finer ducts.
SYMPTOMS.—There are marked differences in the behavior of the more acute cases of catarrh of the bile-ducts and the chronic examples of the same disorder. The former is held to be the most frequent cause of jaundice, whilst the latter is an important element in the so-called bilious state, in lithæmia, and as a secondary condition in some cardiac and pulmonary diseases. Also, the morbid complexus of catarrh of the bile-ducts includes the symptoms of duodenal and gastro-duodenal catarrh.