Part 147

In pyæmia simplex this condition is less marked, although generally present, "while we know septicæmia diminishes or destroys the {964} coagulability of the blood. Hereby the possibility is given, at least on the cadaver, to differentiate between pyæmia simplex and septicæmia, although cases occur of the more fatal septic infection in which the post-mortem condition is a complete or almost complete negative. Therefore, in these cases the differential diagnosis on the cadaver must be limited to this, that we are able to demonstrate the existence of a purulent or ichorous deposit." It will be readily observed that the difference in diagnosis mentioned above relates to pyæmia and septicæmia, and not to the different varieties of the former disease.

The following facts should be constantly kept in mind by the surgeon to enable him to differentiate between the two forms of pyæmia: In pure cases of purulent infection, without metastasis, the disease is called pyæmia simplex, and in cases with metastasis, pyæmia multiplex. The various conditions on which the metastasis may depend are shown by Hueter, who says: "The metastatic abscesses of pyæmia multiplex met with in the lungs, liver, spleen, and other internal organs are regarded, with the greatest probability, as a result of the embolic process. The metastatic inflammation of the serous membranes, of the cellular tissues, and of the parotid glands, and probably also a few metastatic inflammations of the internal organs, are at present supposed to arise from a general inflammatory diathesis." It has already been shown by numerous experiments on animals that metastatic abscesses in the lungs, liver, and other visceral organs only arise after the introduction of ichorous pus, while healthy pus has uniformly failed to produce these results.

It now remains to be shown how the introduction of ichorous pus acts in the production of pyæmia multiplex. The ichorous pus, having found its way into the venous circulation, gives rise to the formation of thrombi in the veins; these clots become more or less broken up, and are carried forward by the blood to the right auricle; from this auricle to the right ventricle; from this ventricle to the pulmonary artery, and through its ramifications to every part of the lungs. In the minute ramifications of this vessel are found wedge-shaped clots of various sizes in different conditions, some softened and others still firm. The possibility of these clots ever passing through the lungs, and afterward being arrested in other visceral organs, has been demonstrated on animals. It has been shown that fine particles of foreign matter injected into the veins have passed through the lungs and subsequently lodged in the liver. This theory enables us to account, upon a mechanical basis, for the existence of the metastatic abscesses in the liver which have apparently originated as the result of primary infection.

In other cases these abscesses are supposed to arise from secondary infection. Thus, ichorous pus, having found its way into the venous circulation, produces primarily venous thrombi, which, as in other instances, break up, the clots being carried in the same manner into the terminal branches of the pulmonary artery, where they are designated as emboli. The first action of the emboli is the mechanical closure of these vessels, thus depriving the surrounding parts of nutrition to a greater or less extent. It will be proper now to recall the fact that the composition of these emboli is such as to favor rapid suppuration; this commonly commences {965} in the clot and surrounding tissues, having been preceded by a brief stage of congestion and inflammation. There is also occasionally found around these points more or less extravasation. The metastatic abscess thus formed in the lungs is favorably situated for the production of secondary infection. From this abscess thrombi arise in the pulmonary veins, which become disintegrated, and are carried to the auricle, thence to the left ventricle, and finally through the aorta, and find lodgment in the terminal branches of the arteries of the various organs, where they produce the characteristic lesions.

The organs which most frequently become the seat of this secondary infection are the liver, spleen, kidneys, brain, and eyes.

Let us now briefly examine this mechanical theory. Do metastatic abscesses arise from a single cause or from a combination of causes? I am inclined to the opinion that the proximal cause of metastatic abscesses in the visceral organs is the existence of emboli in the terminal branches. The vitiated atmosphere surrounding the patient, the existence of a wound, and the formation of ichorous pus are conditions which should not be lost sight of. These are the elements acting on the blood, producing in it morbid changes, and may therefore be regarded as predisposing causes. The morbid conditions of the blood, the increased number of white blood-corpuscles (possibly pus), the disintegration and other changes in the red corpuscles, may be regarded as the exciting causes of metastatic abscesses. It is thus readily observed that emboli may form in the lungs and liver at the same time, or the origin of those in the lungs may precede the formation in other organs.

Is the formation of emboli in the terminal branches of arteries always dependent on the disintegration of thrombi? The answer to this question must, I think, be a negative, although in surgical practice it rarely happens that the emboli take their origin from any other cause. In the large majority of cases, unquestionably, the thrombi primarily exist in the vicinity of the wound in which ichorous pus is generated; but it not infrequently happens during the process of disintegration that broken-up clots are carried forward by the current of blood, receiving accretions on the way, until finally they fill a large venous trunk. In confirmation of these facts relating to the primary origin of thrombi, it is said to have been observed in epidemics of puerperal fever, which were complicated with metastatic abscesses of the visceral organs, that the thrombi occurred in the pelvic veins. In case of wounds of the lower extremity the clot is frequently found in the common iliac vein, although probably it should always be regarded as a secondary formation. In rare cases the only thrombi discovered at the autopsy are found situated far away from the injury.

Observation fully establishes the fact that, after death from pyæmia, pathological changes are much more frequently met with in the lungs than in any of the other organs. This certainly strengthens the embolic theory. Billroth mentions eighty-three cases of true pyæmia multiplex, in which the metastatic abscesses occurred as follows: seventy-five times in the lungs, seventeen times in the spleen, eight times in the liver, and four times in the kidneys. Sedillot remarks that in one hundred cases of pyæmia we find the lungs affected in ninety-nine, the liver and spleen in eight, the muscles in seven, and the heart and peripheric {966} cellular tissue in five cases. The brain and kidneys are comparatively seldom involved.

The theory previously mentioned as the embolic relates to the aggregation of fibrin into clots; but another theory has been recently advanced by E. Wagner, who found in many cases the capillaries in the lungs filled with fat, and was inclined, from the direction it extended in these vessels, to explain a certain number of the pyæmic cases by the fat emboli; but it has been shown that the existence of the fat emboli in pyæmia is purely accidental and possesses no significance. Pyæmia multiplex very frequently occurs without fat emboli, and vice versâ; either process may complicate the other, and so the fat emboli may acquire special importance by obstructing the respiration, and probably also in their way the embolic fat may serve as a carrier of putrid material.

MORBID ANATOMY.--The external appearance of the body varies greatly. The skin, in those cases in which the patient was jaundiced before death, will be found in every part of the body to be of a dark orange or dirty icteric tinge, but in other cases it may present a pale or anæmic appearance. There are also sometimes found circumscribed ecchymoses or purpuric patches, while the edges of ulcers or open wounds are generally of a blackish or dirty yellow color. The lips and finger-nails present a livid appearance; epithelial defects are observed in the cornea, but these had their origin there before the death of the patient.

The eyes in some cases are sunken deeply in their sockets, and where the disease has been protracted there is often very great emaciation. Rigor mortis is commonly well marked after a few hours. When death occurs from puerperal pyæmia there are generally found some indications of the recent parturition, although the principal lacerations or injuries may be confined to the womb. All fluids disappear from external wounds before the death of the patient, and they remain dry afterward.

In some cases the cellular tissue is the seat of diffuse suppuration. The pus formed is thin, fetid, and unhealthy. This suppuration is limited to certain parts of the body, as an injured extremity, or, as frequently happens, it may be found on the trunk and limbs at the same time. The pus in this form of suppuration is exceedingly apt to burrow, on account of the peculiarities of the tissue in which it occurs, and also the condition of the surrounding structures, especially the relaxed and flabby condition of the skin. These abscesses in some instances are superficial, in others deep-seated.

There are few changes which occur in the muscles, and these are not uniform or constant. They are occasionally the seat of abscesses, which have been observed in the heart, tongue, and other organs. The muscles may be of a light-brown or greenish color when they have been covered a considerable time with pus, and are sometimes softened and pultaceous. Suppuration may also take place beneath the fascia of the tendons.

The brain and its membranes are frequently found in a perfectly healthy state after death from pyæmia, although when the diseased process has extended during the life of the patient to the lungs and pleura, giving rise to great dyspnoea, there will generally be observed some congestion of the membranes, an increased quantity of fluid in the brain-substance and ventricles, and also an increased fulness of the meningeal veins and sinuses. Occasionally there have been observed suppurative {967} meningitis, blood extravasations on the surface of the brain, lymph-deposits on the membranes, softening of the cerebral tissues, and circumscribed abscesses in the substance of the brain, which in some cases have been traceable to embolism of its vessels. The changes in the spinal cord and its membranes are probably similar to those found in the brain, but these parts appear to have been rarely examined.

Virchow found emboli of the retinal and choroidal vessels. Heiberg found these vessels occluded with colonies of micrococci. There have also been observed opacity of the cornea, sloughing of the conjunctival epithelium, suppurative infiltration into the periphery of the vitreous body, and deposits of pus in Petit's canal and in the anterior and posterior chambers. Pyæmic ophthalmia has been observed somewhat frequently in puerperal cases, especially when preceded by endocarditis, with deposits on the semilunar or mitral valves. In surgical cases it is rarely seen.

Toynbee "relates several cases of purulent infection following suppuration of the ear. Cases of disease in the mastoid cells terminate fatally, he says, from two different causes: first, from purulent infection, arising from the introduction of pus into the circulation through the lateral sinus; second, from disease of the cerebellum or its membranes. Cases of purulent infection, he further remarks, have not been met with where the disease occurs in the tympanic cavity."

Numerous lesions of the osseous system have been noted in pyæmia, probably from the fact that this disease results very frequently in cases of bone-lesions, but these changes have very little diagnostic importance. The following have been observed: thickening or infiltration of the periosteum, which may be found to separate readily from the bone after the death of the patient, or there may be pus found between the periosteum and the bone. In the bone-structure there were found caries and necrosis, "while in other cases the whole thickness of the compact tissue is perforated in a honeycomb-like manner by minute cavities filled with thickish pus or caseous matter of a pinkish-white color." "To sum up, the chief morbid alterations met with in the bones are congestion, dilatation of the Haversian canals and cancellated tissue, tending to abscess formation, and the excavation of the cavities by the unhealthy pus."

The pathological lesions of the joints commence with marked congestion of the synovial membranes and increase in the synovial fluids, and afterward the fluid is mixed with pus; these conditions are followed by erosion of the cartilage and ligaments, the former thus becoming separated from the bone. Both the small and large joints are occasionally the seat of morbid changes.

The parotid gland is occasionally the seat of a secondary inflammation during the progress of pyæmia, and this may endanger life by interfering with respiration and deglutition. The lymphatic glands are only secondarily affected, and even this takes place very rarely. The changes in the glandular system, when observed, are similar to those which happen in other tissues of the body--viz. congestion, inflammation, and suppuration.

The arteries are usually found empty after death from this disease, and the coats are sometimes apparently thickened. The veins, on the contrary, are commonly found filled, or even distended, with firm fibrinous clots. They are sometimes also found inflamed or altered, although more {968} commonly healthy. The distended condition of the veins gives rise to the cord-like feeling often mentioned by different observers. In some cases of phlebitis there may be pus deposited between the coats of these veins. The most important pathological changes are found in the blood. These changes occur early in the disease, become more marked toward its fatal termination, and may be always studied after death. It is generally admitted that pus is frequently found in the blood of these patients; but it has been shown by numerous experiments that healthy pus never produces the pathological changes which characterize this disease. Pyæmia is only produced by the presence in the blood of ichorous pus or some other decomposing animal substance, or some material having its origin in the decomposition of the same, and no decomposition in these substances is ever effected except through the agency of living organisms. It therefore follows that the discovery of living organisms in the blood of those sick and dead of this disease has given a renewed interest to the study of its pathology. The recent investigations made by Pasteur, Koch, Birch-Hirschfeld, and the London Pathological Society show conclusively that in all cases of pyæmia and septicæmia organisms are present in the blood during the entire course of the disease, and that in the former there is found the globular, and in the latter the rod bacteria. It has further been observed in each morbid condition that the severity of the disease is always increased in proportion to the increase of the organisms in the blood, and that the bacteria found within the body are of the same species as those in the wound from which they have gained admission. The micrococci found in the blood of pyæmic patients are surrounded by the decomposed products of the red and white corpuscles, which appear in the blood-plasma in the form of pale granular bodies. There is likewise in this disease an increased coagulability of the blood, and it steadily increases as the disease progresses. In this condition there may be found in the blood-vessels both thrombi and emboli. The thrombi are occasionally observed as firm fibrinous clots, but they may be likewise found in the rapidly fatal cases to have undergone suppurative changes. These changes begin in the centre of the clots, which often contain true pus or a greenish or puriform fluid.

The pericardium may contain a small amount of serum tinged with blood, but it is seldom covered with recent lymph. Both the lung-tissue and pleuræ are commonly inflamed in this disease. The costal and visceral layers may be agglutinated by old adhesions, but are more commonly united together by recently formed lymph. The pleural cavities often contain some opaque, muddy, sero-purulent fluid, mixed with blood and having masses of lymph floating in it.

The lungs are more frequently the seat of metastatic abscesses and other morbid changes in pyæmia multiplex than any other organs of the body. There may be found emboli in the branches of the pulmonary veins, and in the lung-tissue metastatic abscesses surrounded with capillary congestion and other evidences of inflammation; "The smaller vessels, trying to overcome this afflux of blood, may produce ecchymosis or extravasation beneath the lining membrane of the air-vesicles, but the minute capillary congestions are generally observed as red points studded over the pulmonary surface, which by and by exhibit yellowish-white or bluish-white centres. While one part, generally the lower half of the {969} lung, is thus hepatized, solid, and of a dark greenish color, the remainder of the lung is emphysematous and more or less oedematous. A section of the former presents the same appearance as is observed in the lungs of pneumonic patients. Whether these incipient abscesses are developed from the minute points of congestion before mentioned, by the breaking down of the thrombic clots in their centres, or whether the pus is developed out of the serum exuded by the walls of the engorged capillaries, cannot be easily determined, and has as yet not been decided. These secondary abscesses vary in size from that of a hemp-seed to that of a hen's egg." These are generally situated on the periphery of the lungs and in the lower lobe, although in some cases they are found imbedded deeply in the pulmonary tissue. The contents of these abscesses are similar to those found in other parts of the body in this disease. The bronchial mucous membrane is commonly of a bright pink color, while its secretion is increased in quantity, and may be clear and frothy. These changes are the result of acute bronchial catarrh. Lobular pneumonia has been frequently observed as a complication of pyæmia, and is supposed by some authors to be caused by the vitiated condition of the blood; but probably it is more frequently occasioned by infarctions and embolic abscesses, which have been previously mentioned in this connection.

Billroth and Sedillot observed pathological lesions involving a solution of continuity in the spleen, liver, and kidneys, in the order in which they are mentioned; other authors, however, assert that the liver, next to the lungs, is the most frequent seat of purulent deposits. Enlargement of the spleen is frequently met with in cases of pyæmia multiplex. The metastatic abscesses found in the spleen and kidneys are much smaller than those found in the lungs and liver, but in other respects are of a similar character. The capillary congestion and the accompanying infarctions require no special attention here. The liver, like the spleen, is sometimes enlarged, and at other times is found to have undergone fatty degeneration to a greater or less degree; in which condition its tissues are generally soft and friable. Abscesses in the liver are so much like those in the lungs as to need no separate description. The same may be said of other pathological changes found in this organ in pyæmia multiplex. The abscesses found in the kidneys vary from the size of a hemp-seed to that of a bean, and are surrounded by the usual zone, marking more or less definitely the extent of the inflammation. The capsule is generally healthy. There are also, in very rare cases of this disease, abscesses found in the stomach and intestines, involving the thickness of the mucous membrane; and it is further supposed that these abscesses may be found occasionally on any portion of the mucous membrane lining the alimentary canal. Post-mortem examinations in pyæmia multiplex have established the fact that there is no organ in the body that may not become the seat of pathological lesions in this disease; but there is unquestionably a vast difference in the relative frequency of these changes in the various organs. In some instances of this disease peritonitis is developed, with its concomitant changes in this membrane and the abdominal fluid, which is generally increased in quantity and sometimes slightly tinged with blood, but more frequently remains clear. {970} This inflammation is commonly dependent on an extension of the inflammatory process from a metastatic abscess, which may be situated near the periphery of some organ covered with peritoneum, although it is claimed that pleuritis occasionally occurs in connection with pyæmia independent of metastatic abscesses in the lungs.

The careful study of the pathology of pyæmia multiplex renders it exceedingly probable that the immediate agency in the production of all these lesions is the presence in the blood of a particular species of living organism, and that all the morbid changes which occur in the visceral organs are secondary to those which take place in the blood, but that the former are only dependent on the latter in a minor degree. The pathological changes effected by these organisms seem to be as follows, and to occur in the following order: viz. disorganization of the blood, especially a destruction of the red and white blood-corpuscles; the formation of granular bodies around the organisms out of this débris; the production of an increased coagulability of the blood; the lodgment in the blood-vessels of these granular bodies, which are increased in size by a deposit of fibrin; these obstructions occur most frequently in minute ramifications of the pulmonary arteries; nutrition is effected locally by these infarctions, and generally by the vitiated condition of the blood, which enables the organisms under these favorable circumstances to penetrate the adjacent tissues and produce the metastatic abscesses and other accompanying lesions.

The pathological changes in pyæmia simplex are of the same kind as those which have just been described as characterizing pyæmia multiplex, with the exception of the metastatic abscesses, which are always absent. Furthermore, the disease in both instances is believed to have its origin from the same causes, and the dissimilarities in the pathological lesions are equally susceptible of a rational explanation, as are those of scarlatina simplex and scarlatina maligna.

There were reported by the committee of the London Pathological Society some interesting details pertaining to this form of pyæmia. Their report shows that among the one hundred and fifty-five cases classed as pyæmia there were twenty-four cases without visceral abscesses; and furthermore it shows that in twenty-three of these cases there was no suppuration, although local inflammations affected many of the different tissues, since these patients suffered with arthritis, cellulitis, pleuritis, meningitis, pericarditis, and carditis. It is also added that "the post-mortem appearances, in addition to the local secondary inflammation before noted, were in many cases those changes common to all forms of blood poisoning. Out of the twenty-four cases, the following are noted: Swollen spleen, nine times; congestion of the lungs, ten times; swollen liver, six times; cloudy swelling of the kidney, fourteen times."

In this form of pyæmia it has been supposed by some authors that the materies morbi occasionally produces death before the metastatic abscesses have had time to develop, but this is not always the case. The same committee report on the above-mentioned twenty-four cases, on this point, as follows: "The duration of the cases before the fatal termination was very various. It is tolerably accurately recorded in eighteen cases: of these five died in the first week, five in the second, {971} four in the third, and the remaining four survived to the thirtieth, forty-ninth, fifty-second, and sixty-second days."

The pathology of pyæmia multiplex having been already fully described, and since the only essential difference in these morbid conditions consists in the complete absence of the metastatic abscesses in cases of pyæmia simplex, it is therefore thought unnecessary to dwell here longer on this subject.