Chapter V: Parasites of the Liver (1)

Echinococcus of the Liver; Hydatids of the Liver.

DEFINITION.--The echinococcus is the intermediate or larval stage in the development of the Tænia echinococcus--the completed parasite--whose chief habitat is the intestine of the dog. As the natural and clinical history of parasites is elsewhere treated of, the subject is here confined to the development of echinococci cysts in the liver, its ducts, and vessels.

CAUSES.--The presence of echinococcus vesicles in the liver is due to {1102} the migration of the embryo from the intestinal canal. As Davaine[212] has ascertained by analysis of all the recorded examples previous to the publication of his treatise, echinococci are found in as large a proportion in the liver as in all the other organs combined. This statement is repeated with approval by Cobbold[213] and by Heller.[214] The embryo, set free in the intestine from the food or drink containing the ova, starts on its migration. There are several reasons why the liver is selected for its habitat: it is the largest accessible organ; the common duct and the portal vein offer the most convenient roadway for reaching and penetrating its substance. The exact route or routes of which the parasite avails itself in migrating have not been definitely settled, although Friedreich has shown that the portal vein is the medium of transmission of the Echinococcus multilocularis. The comparative frequency with which the liver is entered indicates that the portal vein is the favorite route of migration.

[Footnote 212: _Traité des Entozoaires et des Maladies vermineuses, etc._, par C. Davaine, Paris, 1877, p. 383.]

[Footnote 213: _Entozoa_, by T. Spencer Cobbold, M.D., F.R.S., London, 1874, p. 275.]

[Footnote 214: In vol. iii of _Ziemssen's Cyclopædia_, p. 561.]

PATHOLOGY AND SYMPTOMS.--The number of echinococci reaching the liver varies from one to ten or twelve or more. They increase in size from the time of their deposit in the organ, and ultimately attain to large proportions. The rapidity of growth depends somewhat on the character of the tissue in which imbedded, and the amount of disturbance of function is determined by the position of the parasite in the organ. Echinococci may be deposited in any part of the liver--in the substance of the organ, in the ducts, or in the vessels--but the most usual site is near the capsule, and, developing outwardly in the direction of least resistance, impart to the outline of the organ an irregular contour. As the echinococci develop, the adjacent parts of the liver pressed upon undergo atrophy, but the connective tissue of the organ contributes to the formation of the dense capsule which envelops them. But as the increase in size is not rapid, although continuous, if the cysts are situated at the periphery and adjacent to the capsule, they may be present for many months without causing any distinct symptoms. In a case occurring under my own observation last year the only symptom which attracted attention was an enlargement of the hepatic region, and on examination a characteristic elastic, irregular, and painless tumor could be readily detected by sight and touch occupying the right hypochondrium and extending into the epigastric and umbilical regions. When the echinococci cysts impinge on the portal vein or on the hepatic duct, there will be caused the usual results of such pressure--ascites or jaundice, or both conditions may occur simultaneously, with obstruction of both vein and duct. When the cysts develop downwardly, the stomach and intestines will be displaced, and nausea and vomiting, diarrhoea or constipation, and, it may be, considerable pain of a colic-like character, will be caused. An upward development of the cysts gives rise to more pronounced disturbances. The diaphragm is pushed upward, the heart displaced, and the lungs, especially the right, compressed. Occasionally the diaphragm is softened and perforated by the pressure of the enlarging cysts, and the lungs are ultimately tunnelled, the parasites being discharged by the bronchi.

{1103} The growth of an echinococcus tumor may spontaneously cease, and then retrograde changes take place, leading to its final disappearance. This arrest of development may occur without any obvious cause, but now and then such a change from the ordinary course of tumors may be effected by an external injury, as a blow on the abdomen, but more frequently the death of the parasite is caused by ulceration into a bile-duct, and the entrance of bile, which is a poison to these hydatids. It sometimes happens that, opening into a duct of large size, the daughter and granddaughter vesicles are slowly discharged through it into the intestine, and thus a cure is effected. Inflammatory action occurring in the cysts, adhesions may form and rupture into a neighboring cavity take place. Direct communication may be established with the intestine, or the cavity of the pleura or peritoneum be entered, with results entirely disastrous.

A necessarily fatal termination must also ensue when the hydatids penetrate the ascending vena cava, but this accident is, fortunately, very rare.

The passage outward through the abdominal wall is an exceedingly uncommon but fortunate issue of echinococcus of the liver, for in this mode the hydatids may be discharged without much difficulty.

The echinococcus vesicle is enveloped in a dense, resisting, and elastic capsule, constructed out of the connective tissue of the part in which it is deposited. The innermost layer of the vesicle is the germinative (endocyst), and from its granular surface are developed the brood-capsules and their scolices--_i.e._ the head with its suckers and crown of hooklets.[215] Each vesicle may contain not only daughter, but also granddaughter, progeny, numbering from a dozen up to many thousands, and they will vary in size from the head of a pin to a pullet's egg. It follows that the mother vesicles must also greatly vary in size: they range from a large pin's head to a child's head. The vesicles or sacs contain a clear, faintly yellowish, or opalescent fluid, neutral or slightly alkaline in reaction, and holding in solution a large per cent. of sodium chloride, but free from albumen. The specific gravity of the fluid ranges from 1007 to 1015, according to the quantity of sodium chloride present. Succinic acid and also hæmatoidin are usual constituents, besides the ingredients already mentioned.

[Footnote 215: _Entozoa_, Cobbold, p. 273 _et seq._, chapter viii.]

Although the form of hydatid or echinococcus cyst above described is the usual one, there is occasionally produced an anomalous development of the parasite, which from its resemblance to colloid cancer was supposed to have this character until Virchow[216] unravelled the mystery by demonstrating its true structure. This form of the parasite is designated Echinococcus multilocularis. Its resemblance to colloid cancer is the more striking because of the tendency of the interior of the mass to undergo degeneration, to disintegrate, and to break up into pus-sacs with greenish, cheesy, and bilious contents. An Echinococcus multilocularis tumor is of almost stony hardness; it has a very dense fibrous structure, intersected by cavities with thick gelatinous contents. These minor cavities[217] are sacs of echinococci, but they depart widely from the typical form, well-defined scolices being seldom encountered.

[Footnote 216: _Archiv für Anat._, Virchow, vol. xi. p. 80.]

[Footnote 217: Carrière, quoted by Davaine, _op. cit._, p. 961.]

{1104} Echinococci of the liver develop very slowly, and it is characteristic of them to attain to very large proportions in most cases without causing any very pronounced symptoms. There are certain signs common to hydatids in any situation; there are others which are due to particular circumstances.

A hydatid tumor of the liver is smooth but somewhat irregular in outline, and elastic, when it develops downward, extending below the margin of the ribs. If, however, it grows upward, the area of hepatic dulness extends in that direction beyond the usual limits; the diaphragm is pushed up, the lungs forced upward to the left and compressed, and the heart also displaced upward toward the left. The extension of the tumor downward, in the direction of least resistance, is more usual. If the walls of the abdomen are sufficiently thin, the tumor large enough, and if made up of many daughter vesicles, there may be evoked by palpation the very characteristic sign known as hydatid purring. To produce this effect an oscillation must be caused by a sudden impulse communicated to the tumor on one side, the hand resting against the other side. This sensation is likened to the impression on the eye of the vibration of a bowl of jelly. Even when there is a well-defined tumor this symptom is comparatively infrequent, but if present it is pathognomonic, since no other kind of tumor possesses the property of oscillation and elastic collision of its several constituents.

When the tumor is so situated as to occlude the hepatic or common duct, jaundice will be a symptom, and when the stomach is pressed upon there will be epigastric oppression and nausea. If the vena cava is impinged on or the portal vein, the usual results--ascites and oedema of the lower extremities and of the scrotum--will be manifest. There is, of course, nothing distinctive in these results.

The Echinococcus multilocularis, situated in the substance of the liver, causes the usual disturbances of a new formation in such a position. Much of the hepatic tissue is destroyed by its growth, and many of the minor ducts closed. Jaundice is an early symptom--the first, indeed, in many cases--and is also one of the most persistent. It is present, according to Griesinger, in 10 out of 13 cases. The usual gastro-intestinal disorders belonging to jaundice occur under these circumstances; also the nervous disturbances of cholæmia.[218]

[Footnote 218: Davaine, _op. cit._, p. 962.]

Enlargement of the spleen is a very frequent symptom, being present, according to Davaine, in 11 out of 13 cases, and, according to Heller, in 25 out of 29 cases, in which this fact was made the subject of direct inquiry.

Pressure on the vena cava causes oedema of the inferior extremities in a small number of cases; and on the vena porta, ascites. There may occur thrombosis of the portal, in which event the ascites will form very quickly, and return as quickly after tapping.

The usually placid course pursued by echinococcus of the liver may be much modified by inflammation and suppuration. Some external injury may develop the inflammation. Having occurred, the clinical history corresponds to other cases of hepatic abscess, and the reader is therefore referred to the section on that topic for fuller information.

DIAGNOSIS.--At the outset of echinococcus of the liver the {1105} differentiation of the tumor from other tumors, and of the disturbances produced by it as contrasted with the effects of other morbid growths, becomes exceedingly difficult, if not impossible. The size, painlessness, elasticity, the purring tremor of the echinococcus tumor, afford a sure basis for constructing a diagnosis, and as ultimately developed they become the means of accurate differentiation from other morbid growths of that locality. All doubt as to the nature of a given hydatid tumor of the liver may be set at rest by the use of the aspirator. The discovery of the characteristic hooklets of the scolex in the fluid withdrawn from the tumor will be conclusive as to the presence of echinococci. The hooklets may be absent, as in the case of acephalocysts, but the fluid is characteristic in other respects: it contains a large quantity of chloride of sodium and is free from albumen.

Very great difficulty is experienced in diagnosticating an echinococcus tumor developing from the upper surface of the liver, pushing the diaphragm and lungs upward and displacing the heart to the left. Whilst the physical signs may be, and are, usually alike when the condition calling for diagnosis has existed for some time, there are means of differentiating in the history of the cases and in the initial symptoms.

The origin and growth of the echinococcus tumor are obscure and free from constitutional disturbance; the onset of a pleuritic exudation is marked by pain, fever, and hurried respiration and by physical signs of a characteristic kind. It is true there are cases of so-called latent pleurisy in which a hydrothorax forms without any well-marked indications, but it will usually be found that some local pain, hurried breathing, or other symptoms existed from the beginning. Those cases of hydrothorax accompanying renal and cardiac diseases are readily enough associated with their original cause.

Echinococcus of the liver may be confounded with abscess of the liver, but a differentiation can be readily made by attention to a few considerations, except in the rare condition of the Echinococcus multilocularis which has proceeded to suppuration. In this latter condition there are no means of differentiation, since an abscess-formation has already occurred, nor is there any need to attempt a distinction without the occasion of a difference. Echinococcus differs from abscess in history, in the character of the swelling, and in progress. Abscess of the liver is preceded by paroxysms of hepatic colic, by inflammatory ulceration of some part of the intestinal tract, or by local injury--traumatism. The onset of a hydatid tumor is silent and painless. The swelling of the liver when an abscess forms is not considerable at any time, and appears to be a uniform enlargement of the organ, except when the pus tends to make its way through the walls of the abdomen externally. An enlarging echinococcus tumor is an obvious projection from the surface of the liver at some point, and it does not have the characteristic tenderness, the fluctuation of an abscess matured and ready to discharge, and the constitutional disturbance; but it does have a peculiar elasticity, and now and then may present that eminently characteristic sign, the purring tremor. The use of the exploring-trocar will usually suffice to clear up all doubts by the withdrawal of the characteristic fluid of the hydatid cyst or of pus.

DURATION AND TERMINATION.--The progress of an echinococcus {1106} tumor is exceedingly slow, and the development of symptoms produced by its extension is early or late according to its position and to the nature of the parts impinged on. A spontaneous cure may take place under the rather rare circumstances of an opening into the hepatic duct or one of its principal divisions, and the gradual discharge of the cysts by this outlet into the intestine. Next to this mode of termination, the most fortunate direction taken by the enlarging cysts is through the walls of the abdomen externally. When the growth is upward through the lungs, the symptoms belonging to empyema or hydrothorax, with pulmonary abscess, ensue, and the termination is fatal after a protracted course. Rupture into the peritoneal cavity is a fatal event. Ulceration into the intestine, and the discharge of the cysts through the route thus made, may effect a cure, but more frequently the fistulous communication becomes a means of forming a fecal abscess.

The result in any case of hydatids of the liver is much influenced by the mode of treatment adopted and the period at which it is undertaken. As these parasites can be readily reached and destroyed by safe means, obviously the more early the diagnosis is made and the treatment carried out, the less the injury done to the hepatic structures and neighboring parts.

TREATMENT.--Prophylactic.--As the intestine of the dog is the natural habitat of the Tænia echinococcus, and as the hydatid is the first stage in the development of the ovum and the second in the life-history of the parasite, the means of prophylaxis consist in preventing contamination of human food and water with the dog's excrement, which contains the ova of the parasite. In Iceland, where hydatid disease is very prevalent, dogs and human beings living in the same huts and obtaining their water-supply by melting the snow just about them, contamination of food and drink must readily occur. In this country such conditions cannot exist; nevertheless, cases of hydatids are not infrequent. The chief, if not the only, source of contamination is through the consumption of such uncooked vegetables as lettuce, celery, cabbage, etc., in the folds of which the ova may be retained, and from which an ordinary washing does not suffice to detach them. It follows that such articles of food should be minutely inspected and cleansed before being placed on the table.

Boiling and filtration are the means of removing impurities of this kind from potable waters.

Therapeutical.--The remedial management of cases of Tænia echinococcus is necessarily restricted to that stage in their development when by increasing size the functions of organs begin to be affected. Internal medicines given with the view to arrest the growth of the parasite are useless. Formerly, such attempts were made and successes were claimed, but it is now known that no medicine can act on organisms enclosed as these are in a dense capsule. It is needless to occupy space with therapeutical details of this kind, but mention may be made of the agents that were supposed to be effective. Laennec held that baths of a solution of common salt had a distinct curative effect. The internal use of iodide of potassium and the local application of iodine paint were believed to cure a case in St. George's Hospital, London, in the practice of Mr. Cæsar Hawkins. Kameela was, in Iceland, supposed to have a curative effect, but notwithstanding this the physicians of that island resort to very heroical surgical methods in the treatment of this affection.

{1107} The one means of relief consists in the removal of the vesicles, either by suitable incisions or by compassing the death of the parasite, after which the power of nature may be adequate to the cure. In Iceland large incisions are made into the tumor at its most prominent part, and, although accidents are not uncommon, the results in many cases are eminently satisfactory. The accidents are shock, hemorrhage, and especially peritonitis. Under favorable circumstances now no procedure is more satisfactory in its results than free incision and drainage. The tumor should be prominent, adherent all round to the peritoneum, and the walls of the abdomen thin to ensure complete success without accident. At the present time, so great have been the advances in abdominal surgery, this operative procedure may be preferable in some few cases presenting the favoring conditions above mentioned.

Very simple expedients, however, suffice in most cases. The most simple is puncture. This is now much practised in Iceland, and, as the statistics show, with considerable success. Thus, Hjaltelin[219] reports 100 cases cured in this way, and in his own hands this expedient proved successful in 41 out of 50 cases operated on. In Australia, where hydatid disease is also quite common, simple puncture has effected a large proportion of cures,[220] and is the method of treatment usually pursued. In England puncture has the approval of some of the best authorities.[221]

[Footnote 219: Davaine, _op. cit._, p. 605.]

[Footnote 220: _The Medical Times and Gazette_, August, 1873, p. 164.]

[Footnote 221: _Transactions of the Clinical Society_ for 1872: discussion participated in by Gull, Bryant, Greenhow, etc.]

The mode of performing this operation consists in the introduction of an exploring-trocar into the most prominent part of the tumor. It may be withdrawn at once or be permitted to remain for a few minutes to several hours. The dangers are suppuration in the sac and peritonitis; but the former, although sometimes accompanied by severe constitutional symptoms, is not likely to endanger life, and even formidable disturbances due to the latter are usually recovered from. The facts show that puncture very rarely indeed causes dangerous, especially fatal, symptoms. An eruption of urticaria has been observed to follow puncture with the trocar, and also aspiration, in a considerable proportion of the cases, but it has no special significance.

Since the introduction of the aspirateur, puncture and withdrawal of the fluid by means of this instrument has been practised more frequently, and this appears to be a more effective procedure, than simple puncture with an exploring-trocar, although in most cases the escape of the contained fluids suffices to destroy the parasite. The aspirateur is less likely to permit the escape of fluid into the peritoneal cavity or the entrance of air into a vein punctured by accident. If puncture with the trocar or aspiration be practised, shall all the fluid be withdrawn at once? The answer to this question may be decided by the character of the sac. Does it contain daughter and granddaughter vesicles? If so, one puncture may not permit the escape of much fluid; but in any event it is the practice of the most judicious and experienced authorities[222] to withdraw as much as possible of the contents of the cysts at the first operation. Formerly, a method practised by some French surgeons consisted in successive tappings, a small quantity of fluid being drawn off each time.[223] {1108} There is no good reason for this method of treatment now, and it seems to have been discontinued.

[Footnote 222: _Transactions of the Clinical Society_, _loc. cit._]

[Footnote 223: Davaine, _supra_.]

Yet another method of treatment, but less effective than puncture or aspiration, consists in injecting into the sac, after the removal of its contained fluid, certain agents toxic to hydatids. A solution of the extract of fern, alcohol, solution or tincture of iodine, and bile, are the chief remedies thus employed. It has long been known that bile is destructive of these parasites, and cases have occurred of spontaneous cure in which the opening of the growing cysts into a bile-duct has secured the entrance of bile and consequent arrest of growth and atrophy of the hydatids. Several successful cases have been reported in which the injection of aspidium (male fern) was the effective agent, but the threatening symptoms produced by it, and the comparative freedom of other methods of treatment from such disturbances, do not recommend the injections of fern. In the case reported by Pavy[224] the extract of fern was mixed with a solution of potassa.

[Footnote 224: _Lancet_ (London), July, 1865.]

Injections of iodine in solution or in the form of tincture have been more frequently practised than of any other material. Davaine,[225] who finds it less successful than simple puncture and aspiration, recommends, as affording the best results, a dilute aqueous solution of iodine. Alcohol, a solution of permanganate of potassium, and various antiseptic agents have been used to some extent, but none of them possess any advantages over more simple measures.

[Footnote 225: _Op. cit._, p. 650.]

The latest proposal for the treatment of hydatid cysts, and probably the most effective consistent with entire safety, is electrolysis. Originally suggested by Althaus[226] to those who first employed the measure on any considerable scale, it had been mentioned thirty years before by Budd, and appears to have been first practised in Iceland on a single case. The first elaborate attempt to establish electrolysis on a sound basis as a regular procedure was made by C. Hilton Fagge and Mr. Arthur E. Durham.[227] They operated on eight cases, and all were successful. The method consists in the introduction of two needles connected with the negative pole, and the application of the positive--a moistened sponge--on the exterior in the neighborhood of the hepatic region. The strength of current employed by Fagge and Durham was that furnished by a battery of ten cells, and which by previous trial was found to decompose a saline solution. The two electrolytic needles, connected with wires attached to the negative pole, were introduced into the most prominent part of the tumor about two inches apart. The current was allowed to pass about ten minutes usually, sometimes a little longer, the sponge on the exterior--the positive pole--being shifted occasionally. The immediate effects are not considerable. The tumor may be rendered somewhat more tense and appear to be enlarged, but more frequently it becomes softer and is lessened in size, the increase of size being due to the disengagement of hydrogen gas, and the diminution caused by the escape of more or less fluid. The immediate effects of the operation varied. In one case no symptom followed, and in this the result was regarded as doubtful, although a cure was considered probable. In the others more or less {1109} constitutional disturbance followed, the symptoms being pain and fever, the temperature ranging between 100° and 103° F. The duration of the fever was from two to nineteen days, the latter in one case only. As has been observed in some of the cases treated by puncture or by aspiration, a rash appeared on the skin--in some instances scarlatinous, in others of urticaria. It is a curious circumstance that an eruption of urticaria is reported to have appeared in one subject in whom a rupture of the sac into the peritoneal cavity is supposed to have occurred.

[Footnote 226: _On the Electrolytic Treatment of Tumors, etc._, London, 1867.]

[Footnote 227: _Medico-Chirurgical Transactions_, 1871, p. 1 _et seq._]

Although so little change in the tumor occurs immediately after the operation, yet it undergoes slow absorption, and ultimately disappears. The time occupied in the disappearance of the tumor varies from a few weeks to many months, the difference being due probably to the situation of the growth, those occupying the substance of the liver requiring a longer time to fill up.

Fagge and Durham report a case in which simple acupuncture was followed by a result apparently as good as obtained by electrolysis, and other similar experiences have been published. If the simple introduction of a needle suffices to arrest the growth of a hydatid cyst and induce its atrophy, of course the more complex procedures will be abandoned.

The tendency of the treatment of hydatid cysts has constantly been toward simplicity, and the success occurs in a direct ratio thereto. In forming an estimate of the relative value of the methods of treatment, the average of mortality of each plan becomes the most important factor. Simple tapping and paracentesis, the most frequently adopted mode of treatment, is not without immediate and remote danger. Of 46 cases carefully tabulated by Murchison,[228] there were 3 deaths properly attributable to the operation; but the after results--suppuration of the cyst and its consequences, peritonitis, etc.--cannot be measured so accurately. About two-thirds of the cases thus treated result in cure, and in a majority of these a single operation suffices. The injection of the various substances which have been employed for that purpose does not seem to increase the proportion of cures, and their use distinctly enhances the dangers of the treatment. At present, the decision as to the method of treatment to be employed in any case should be made between simple tapping, electrolysis, and acupuncture. Of these, the last mentioned, it can hardly be doubted, is the method which is most desirable, for although it has not been employed so largely as the others, thus far the results have been better: the percentage of recoveries without accident has been higher relatively than by other methods of treatment. As acupuncture presents no special difficulties or dangers, and is but little painful, it may be tried first, reserving more formidable measures for the failures by this simple expedient.

[Footnote 228: _Clinical Lectures on Diseases of the Liver_, _loc. cit._]

Distoma hepaticum and Distoma lanceolatum (Liver-Flukes).

The Distoma hepaticum, entitled by Linnæus Fasciola hepatica, occurs very frequently in herbivorous animals and occasionally in the biliary {1110} passages of man.[229] It is, however, less important than the Distoma lanceolatum, which, although much smaller than the former, occurs in much larger numbers.

[Footnote 229: Davaine, _Traité des Entozoaires_, Paris, 1877, p. 240 _et seq._; also, Cobbold, _Entozoa_, p. 148.]

Distoma hepaticum is a leech-like parasite from 25 to 30 mm. in length, of a brownish color, smooth to the naked eye, but thickly covered with minute spikes or spines to be seen with a low power, and provided with a cephalic (entrance to oral cavity) and an abdominal sucking disk, which are also organs of locomotion. The Distoma lanceolatum owes its name to its lancet shape; it is smaller than D. hepaticum, measuring about 8 mm. in length and half this or less in width; it is unprovided with spines, but contains two suckers at the side. Both parasites are hermaphrodite; the ova, according to Cobbold (p. 166), have "an average longitudinal diameter of 1/180, whilst their greatest transversal measurement is about 1/270." These ova are capable of some movement, provided as they are with a ciliated envelope.

The disease known as the rot in sheep, and a peculiar cachexia entitled by Davaine la cachexie aqueuse, are caused by the presence of distoma. The ova gain access to man through the use of unwashed cress, lettuce, and similar vegetables eaten in the raw state, and in drinking-water. Fortunately, this accident is rare. The number of reported examples collected from all sources by the indefatigable Davaine is twelve.[230]

[Footnote 230: _Ibid._, p. 253 _et seq._]

The larger distoma passes into the common and hepatic duct and gall-bladder, whilst the smaller (lanceolatum) enters the finer ramifications, and, there multiplying, several consequences may ensue. The irritation caused by their presence and development will excite a more or less severe cholangitis, or, accumulating in sufficient numbers, an actual obstruction will be induced, and jaundice and structural alterations of the liver will in turn be brought on.

The DIAGNOSIS of such a malady is, in the very nature of the case, uncertain at best, and in most cases impossible. Nevertheless, it may be made in rare instances. The existence of the rot may cast suspicion on the mutton and kitchen vegetables so situated as to suggest the possibility of contamination with the ova of distoma. Definite and conclusive information will be afforded by the presence of the ova, still more of the more or less fully-developed parasite, in the feces of a patient effected by the symptoms of catarrhal jaundice or occlusion of the biliary passages. By tapping the gall-bladder parasites may be withdrawn.

The SYMPTOMS are those common to cases of catarrh of the bile-ducts (cholangitis), catarrhal jaundice, or occlusion of the passages, as may be. As these have been detailed under their respective heads, it is not necessary to repeat the observations already made.

As regards the TREATMENT, in addition to the methods of management recommended in such cases it may be stated that the use of certain parasiticides offers a reasonable prospect of good results. Creasote, bichloride of mercury, thymol, eucalyptol, oil of wintergreen (gaultheria), and similar agents are rational remedies and should be fairly tried.

{1111} Parasites in the Portal Vein.

The entozoön which by its presence in the blood causes the disease chyluria also inhabits the portal vein. In some parts of the world--Brazil more especially--this disease is exceedingly common. It has occurred also in two or three instances in England, and the writer has had a case within the past year (1884) in Philadelphia. The parasites in this case were found in immense numbers in the urine.

The blood of the portal vein sometimes is actually filled, and the liver substance itself is penetrated, by them, but nothing is known of the alterations they induce in these organs. When cases of hæmaturia or chylous urine due to the Filaria sanguinis hominis occur, the changes are not confined to the urinary organs, but often, doubtless, involve the liver. There are no signs in the present state of our knowledge by which the existence of these parasites in the portal vein and liver can be determined.

{1112}

DISEASES OF THE PANCREAS.

BY LOUIS STARR, M.D.

Until the middle of the seventeenth century the prevalent views upon the functions and diseases of the pancreas were vague in the extreme. By some the organ was regarded simply as a cushion provided for the protection of the neighboring blood-vessels and nerves; by others it was looked upon as the seat of lesion in many very diverse diseases, as ague, hypochondriasis, melancholia, and so on.

In 1642, Wirsung's discovery of an excretory duct demonstrated the fact that the pancreas was a special organ, and initiated the successful investigation of the physiology and pathology of the gland. For many years after this, however, little progress was made, and it is only comparatively recent investigations that have furnished definite and reliable information upon the subject. Even now our knowledge of the clinical and pathological features of diseases of the pancreas is far behind that of many of the other viscera of the body, the chief reasons for this being the uncertainty in regard to the physiology of the gland and the rarity with which its lesions are primary and uncomplicated.

ANATOMY AND PHYSIOLOGY.--The pancreas is a long, somewhat flattened, narrow, acinous gland, pinkish-white in color, and of looser texture than the salivary glands, which it otherwise closely resembles in structure. It is hammer-shaped, measures from six to eight inches in length, one and a half inches in breadth, and about three-fourths of an inch in thickness, and varies in weight from three to five ounces. The gland is situated in the upper part of the abdominal cavity; the expanded portion, or head, lies in the concavity of the duodenum; thence it extends transversely across the epigastric and both hypochondriac regions on a level with the first lumbar vertebra and in contact with the posterior abdominal wall. As it passes toward the left it gradually decreases in size, and the narrowest part, or tail, rests against the spleen. Behind the organ are the crura of the diaphragm, the aorta, the inferior cava, the superior mesenteric vessels, and the solar plexus; in front of it, the stomach and the left lobe of the liver. Its anterior surface alone is invested with peritoneum, being covered by the posterior layer of the lesser omentum. The ascending portion of the head is intimately connected with the duodenum by dense connective tissue, and at times the descending portion, by extending backward and outward, forms an almost complete ring around the gut; the body is loosely attached by connective tissue to the posterior abdominal wall, and the {1113} left extremity and tail are joined to the left kidney and suprarenal capsule and to the spleen by loose areolar tissue. The gland is supplied with arterial blood by branches springing from the pancreatico-duodenal and splenic vessels; its veins join the splenic and superior mesenteric veins; its lymphatics communicate with the lumbar glands; and its nerves are branches from the solar plexus. The principal excretory duct, the canal of Wirsung, has at its widest part the calibre of a goose-quill. It begins by the union of five small branches at the tail, and extends transversely through the substance of the gland from left to right, nearer the lower than the upper border, and the anterior than the posterior surface; it is joined throughout its course by numerous small branches from the acini, which enter it at acute angles. In the head the duct curves slightly downward, and as a rule opens with the ductus choledochus into the ampulla of Vater in the second portion of the duodenum; sometimes, however, it has a separate opening into the intestine. A second, smaller, duct runs from the ascending portion of the head, and usually joins the main duct, but may also open independently.

The acini of the gland are from .045 mm. to .090 mm. in diameter, and are composed of a very thin membrane lined with pavement cells. The thin walls of the excretory ducts are formed of connective tissue and elastic fibres, and are lined by a single layer of small cylindrical epithelial cells. The terminal extremities of the ducts form a complete network around the glandular cells, resembling the intralobular biliary canaliculi. The acini are imbedded in a mass of adipose tissue which contains the vessels and nerves.

The topographical relation of the head of the pancreas to the ductus choledochus is of clinical importance. As a rule (fifteen times in twenty-two, Wyss), the bile-duct descends near the head, toward the duodenum; frequently it runs through this part of the organ, being either partially or entirely surrounded by the gland substance. Now, when the bile-duct merely passes over the pancreas, any enlargement, unless excessive, would simply push it aside, but when it passes through the head, a comparatively slight amount of disease is sufficient to close it entirely and cause jaundice.

It is only since the observations of Bernard in 1848 that the prominence of the pancreatic juice as a digestive fluid has been recognized. It fulfils several important purposes: in the first place, it emulsifies the fatty articles of food; secondly, it converts starch and cane-sugar into glucose; and, finally, it supplements the action of the gastric juice upon nitrogenous materials and completes their digestion. Each of these changes is probably brought about through the agency of a special ferment (Danilewsky). The pancreatic juice is not secreted continuously. According to the observations of Bernstein, there are two separate secretory flows following each ingestion of food--one occurring shortly after the food enters the stomach; the other a few hours later, corresponding in time to the passage of the food from the stomach into the intestine, the latter being followed by a period of rest until the next meal. Both the condition of nausea and the act of vomiting arrest the secretion. When the vagus is divided and the central extremity of the cut nerve is irritated, the secretion is also arrested, and remains checked {1114} for a long time. The arrest in each instance is attributed to reflex action of the spinal cord and sympathetic nerve. At the same time, irritation of the mucous membrane of the stomach caused by the presence of food increases the flow of pancreatic juice, and so too does simple section of the nerves which accompany the arteries. It would seem, therefore, that the gland is under the influence of two sets of nerves from the vagus--one inhibiting, the other exciting, its secretion.

GENERAL ETIOLOGY.--Pancreatic disease occurs more frequently in men than in women. No period of life is exempt from it, but it is most commonly met with in the aged. The predisposing causes are constitutional syphilis, pregnancy, and hereditary tendency. Among the apparent exciting causes may be mentioned the habitual over-use of alcoholic drinks, gluttony, the excessive use of tobacco, suppression of the menstrual flux, the abuse of purgatives, excessive and prolonged mercurial medication, and mechanical injuries, either prolonged pressure or blows upon the epigastrium. As a secondary affection, disease of the pancreas is associated with chronic diseases of the heart, lungs, liver, alimentary canal, and abdominal glands, and the organ may be the seat of metastatic abscesses and tumors.

GENERAL SYMPTOMATOLOGY.--The objective symptoms are--rapid and extreme emaciation of the entire body; sialorrhoea; obstinate diarrhoea with viscid stools; fatty stools; lipuria; and the presence of masses of undigested striped muscular fibres in the stools.

The well-established fat-absorbing and peptonizing properties of the pancreatic juice furnish a ready explanation of the wasting of the body which occurs when this secretion is arrested, diminished in quantity, or altered in quality by disease. Emaciation is not a constant symptom of pancreatic disease. A number of cases are mentioned by Abercrombie, Claessen, and Schiff in which, notwithstanding disease of the gland and complete closure of the duct, revealed by post-mortem examination, the patients during life were not only well nourished, but even moderately corpulent. In such instances it is probable that the digestive functions of the absent pancreatic juice are more or less adequately performed by the bile and succus entericus. When present, emaciation is an early symptom; it is at the same time progressive, and is usually very intense in degree, being most marked in those cases where there is associated hepatic disease or obstruction to the passage of bile into the intestine, where the disease of the pancreas interferes mechanically with the processes of nutrition by pressing upon the pyloric extremity of the stomach or upon the duodenum, and when the organ is the seat of carcinomatous growths. In the last-named condition, in addition to the perversion or arrest of the secretion, the loss of flesh is attributable to the general causes of malnutrition attendant upon carcinoma wherever situated.

Sialorrhoea, or an excessive secretion from the salivary glands, is noticeable as a symptom of disease of the pancreas only when there is an associated lesion of the stomach, either of a catarrhal or cancerous nature. Under these circumstances a quantity--six or eight fluidounces--of a colorless, slightly opalescent, and adhesive and alkaline fluid may be expelled from the mouth at once as an early morning pyrosis; or by frequent and repeated acts of expectoration, following a sudden filling of the mouth with fluid, a large bulk of thin saliva may be expelled {1115} during the day. This hypersecretion must not be looked upon as any indication of an especial sympathy existing between the salivary glands and the pancreas, neither can it be regarded as a pancreatic flux with a regurgitation of the fluid from the duodenum into the stomach and thence through the oesophagus into the mouth, since during the nausea that must always attend the passage of the intestinal contents into the stomach the pancreatic secretion is arrested, and since the liquid contains salivary, and not pancreatic, elements.

The diarrhoea pancreatica is the least constant of all the objective symptoms; in fact, constipation is present in many pancreatic affections, notably carcinoma. The fecal evacuations in this condition are frequent, thin, viscid, and contain an abundance of leucin. Under the microscope the leucin appears either in the form of concentrically sheathed globules, or as small crystalline rods and scales collected together in the form of wheels or aggregated in clusters. This form of diarrhoea may be attributed to a hypersecretion from the pancreas.

That the presence of fat in the stools is an important diagnostic symptom of pancreatic disease is proved both by clinical and experimental observations. The characters of these stools vary considerably. The fat may appear mixed with the feces in small lumps, ranging in size from a pea to a hazelnut, yellowish-white in color, soluble in æther, and easily melted and burned. Again, after the evacuation has become cool fat may be seen covering the fecal masses, collected into a thick cake around the edges of the containing vessel, or, when the feces are liquid, floating as free oil on the surface. Finally, the fat may be in a crystalline form, the crystals being needle-shaped and aggregated into sheaves and tufts. The quantity of fat also varies. It may be present only in small quantities, or may even be entirely absent from the evacuations in those cases in which the secretion from the pancreas is simply diminished, and the amount is greatest in those instances where there is a simultaneous arrest of the pancreatic and hepatic secretions. It must be remembered, too, that even in health the stools may contain fat; this occurs when an excess of oleaginous food is consumed and after the administration of castor oil or cod-liver oil. These conditions must be eliminated, therefore, in estimating the value of fatty stools as a diagnostic symptom; if, then, at the same time, coincident disease of the liver can be excluded, the symptom becomes almost pathognomonic. The appearance of fat in the stools may be due not only to an arrest of the pancreatic secretion, but also to pressure upon the large lymphatic trunks, interfering with the circulation of the chyle and checking the absorption of fat from the intestine.

Usually, the amount of fat expelled is in direct proportion to the quantity consumed, but occasionally the former greatly exceeds the latter. In such cases there must be some other source for the evacuated fat than the food; and it is probable that fat from the adipose tissue passes into the blood, and thence through the mesenteric vessels into the intestine. This theory would likewise account in part for the rapid and extreme wasting, and for another less frequently observed symptom--namely, lipuria. A case is recorded by Clark of medullary cancer of the pancreas with nutmeg liver, and another by Bowditch of cancer of the pancreas and liver in which lipuria was noted. The fat was observed, after the urine had cooled, floating about on the surface in masses or globules; differing, {1116} therefore, from chyluria, for in this condition the fat is present in the form of an emulsion, and gives the urine either a uniform milk-like appearance, or, after it has been allowed to stand, rests upon the surface in a creamy layer.

When the pancreatic secretion is arrested, most of the animal food which has escaped gastric digestion will pass unchanged through the intestine and give rise to another characteristic condition of the evacuations--namely, the presence in the feces of undigested striped muscular fibres. The amount of these fibres, and indeed their appearance at all in any given case, will depend directly upon the nature of the food consumed.

SUBJECTIVE SYMPTOMS.--The subjective symptoms of disease of the pancreas are abnormal sensations in the epigastrium, and pain.

The abnormal sensations in the epigastrium are weight and pressure, attended at times by præcordial oppression and discomfort. The feeling of weight is usually deep-seated, may be intermittent or constant, and is generally increased or developed by pressure. It is often influenced by position, the assumption of the erect posture or turning from side to side giving rise to a stretching or dragging sensation, as if a heavy body were falling downward or moving about in the upper abdomen.

The pain may be due either to an inflammation of the peritoneum covering the gland or to pressure upon the solar plexus, and consequently varies in character. When it depends upon localized peritonitis, it is constant, circumscribed, and deeply seated in the epigastrium at a point midway between the tip of the ensiform cartilage and the umbilicus; it is rather acute, and is greatly augmented by pressure. The second variety occurs in paroxysms, and is neuralgic in character, the sharp, excessively severe lancinating pains extending from the epigastrium through to the back, upward into the thorax, and downward into the abdomen. These paroxysms--in reality attacks of coeliac neuralgia--are attended by great anxiety, restlessness, and oppression and a tendency to syncope. That calculi in the duct of Wirsung, tightly grasped at the position of arrest, may give rise to paroxysms of pain analogous to biliary colic, cannot be doubted, though there are no positive facts in support of this view.

PRESSURE SYMPTOMS.--When the pancreas becomes enlarged it encroaches upon the neighboring blood-vessels and viscera, interferes with their functions, and thus produces prominent symptoms.

The ductus choledochus from its close relation to the head of the gland is especially liable to become obstructed, with the consequent production of chronic jaundice and the general effects of the absence of bile from the intestinal canal. Pressure upon the portal vein gives rise to enlargement of the spleen; on the inferior cava, to oedema of the feet and legs; and on the aorta, occasionally, to aneurismal dilatation of the vessel above the point of obstruction and to subsequent alteration in the size of the heart. By encroaching on the stomach an enlarged pancreas may cause either displacement of the viscus or stenosis at its pyloric extremity, attended with occasional vomiting of large quantities of grumous, fermenting liquid, pain, constipation, general failure of health, and the distinctive physical signs of dilatation of the stomach. The duodenum may also be pressed upon and more or less occluded, and pain and vomiting occur several hours after food is taken. Occasionally hydronephrosis is {1117} produced, the accumulation being usually in the right kidney and due to obstruction of the corresponding ureter.

A sufficient number of cases have been collected to show that there is an intimate connection between disease of the pancreas and diabetes mellitus. One or other condition may take the precedence, melituria occurring during the progress of pancreatic disease, demonstrating the onset of diabetes, and the appearance of fatty stools in diabetes a secondary involvement of the pancreas. Various theories have been advanced to account for this association, but the true explanation seems to be based upon the experiments of Munk and Klebs. By experimenting upon dogs these observers found that extirpation of the solar plexus produced either permanent or temporary diabetes, whereas section of the hepatic and splanchnic nerves, removal of the pancreas, or ligature of the duct of Wirsung was without effect. From the intimate anatomical relation of the pancreas to the solar plexus it is easy to understand how disease of the gland may give rise to alterations in the nerve-structure, either by direct pressure or by the extension of inflammation along the nerve-fibres connecting the gland with the ganglia; and these alterations in time produce diabetes. In the instances in which diabetes is the primary affection the condition of the pancreas, as proved by post-mortem section, is usually one of simple or fatty atrophy; and it may be assumed that a lesion of the solar plexus is the cause of both diseases, the changes in the pancreas being produced in a similar way to the atrophy of the submaxillary gland after section of the vaso-motor nerves in Bernard's experiments.

The same nerve-lesion may give rise to bronzing of the skin, and two cases are recorded in which disease of the pancreas (cheesy infiltration, cancer) was attended by this symptom.

PHYSICAL SIGNS.--To make a successful exploration of the pancreas the stomach and colon should be as far as possible empty, and the patient placed in a position, with the head and shoulders slightly elevated and the thighs drawn up toward the belly, to relax the abdominal muscles; or if necessary this relaxation must be brought about by the administration of æther. The knee-elbow position is often preferable to the dorsal position in practising palpation.

The condition of the gland giving rise to physical signs is one of enlargement, affecting chiefly and primarily its head, and due generally to the presence of some morbid growth.

Inspection reveals either a diffuse bulging of the upper third of the abdomen to the right of the median line, or a well-defined tumor situated beneath the right costal border, about the line of junction of the right hypochondriac and epigastric regions. Often the pancreatic tumor does not come in direct contact with the abdominal wall, but presses against and thrusts forward the left lobe of the liver, producing simply a prominence in the epigastrium. In the first condition palpation elicits an ill-defined sense of resistance; in the second, the fingers readily outline a tumor, which is slightly movable, rounded in shape, firm or fluctuating, with a smooth or nodulated surface, usually tender to the touch, and often giving a false impulse transmitted from the aorta lying beneath; and in the third, the smooth surface and the sharp edge of the left lobe of the liver are easily distinguishable.

{1118} Percussion over a pancreatic tumor is commonly dully-tympanitic, absolute flatness occurring only when it is very large and comes directly in contact with the abdominal wall, pushing aside the stomach and intestines.

On auscultation a blowing murmur may, in some instances, be heard over the tumor. These murmurs are due to pressure upon the aorta, and must be distinguished from the sound produced in aneurism of this vessel.

The various complications of pancreatic disease, such as dilatation of the stomach, ascites, and secondary lesions of the liver, greatly modify the physical signs, and sometimes entirely prevent an exploration of the gland.

INFLAMMATORY AFFECTIONS OF THE PANCREAS.

Acute Idiopathic Pancreatitis.

This is a rare disease. It occurs most frequently in males during and after adult life, and the strumous diathesis appears to predispose to it. Intemperance, the suppression of normal or morbid discharges, and traumatism act as exciting causes.

ANATOMICAL APPEARANCES.--The pathological changes may be divided into two stages. In the first the gland is deep red in color, intensely injected with blood, greatly increased in consistence, enlarged to the extent of two or three times its normal size, and when an incision is made the divided lobules feel firm and crisp. The interlobular tissue is sometimes dotted with bloody points, and the same hemorrhagic changes may occur in the connective tissue surrounding the gland. In this stage resolution may occur or the inflammation may pass into suppuration. At the beginning of the second, or suppurative, stage numerous minute collections of pus are seen scattered throughout the gland in the interacinous tissue; these gradually collect into a single large abscess, and at times the whole gland is converted into a mere pus-sac, the capsule being much thickened. In other instances the formation of pus is entirely peripancreatic. The pus is usually inodorous and creamy, but is sometimes grayish-white or greenish in color; it then has a faint disagreeable odor, and occasionally is very fetid. When mixed with pancreatic juice it becomes clear and yellowish in color, and contains numerous minute curd-like masses.

In the first stage secondary peritonitis may arise from a simple extension of the inflammatory process, and bands of lymph are formed, gluing the pancreas to the neighboring organs. In the second, fatal acute peritonitis may result from the bursting of an abscess into the peritoneal cavity. These abscesses also occasionally open into the duodenum or stomach. Gangrene and peripancreatic sloughing occur very exceptionally, and are probably due to extensive hemorrhagic changes.