Part 8

The smaller lymph-spaces of the connective tissue in various parts of the body are the frequent seat of the inflammatory oedema, so called, whose presence is an important indication of the direction assumed by a {48} spreading inflammation, as well as a suggestion of the frequent virulence of its cause.

In general, the serous inflammations are to be regarded as less severe than other varieties, or as representing an early stage of what later may be otherwise characterized by a change in the nature of the products.

The purulent variety of inflammation is present when the exudation is abundantly cellular. As has already been stated, such cells are, for the most part, white blood-corpuscles. The purulent exudation, like the serous variety, may appear either on surfaces, when the term secretion is applied, or within the lymph-spaces of the connective tissue over a considerable space, when the pus is said to be infiltrated. When the infiltration is more circumscribed and the walls of the affected lymph-spaces are destroyed, so that adjoining cavities are thrown into larger holes, an abscess is present, from whose wall pus is constantly derived, while the inflammation is progressive.

The attention of the surgeon, in particular, has been directed to the isolation of the immediate cause of suppurative inflammation, and the modern, antiseptic, treatment of wounds is essentially based upon the view of the infectious origin of pus. The frequent presence of microbia in purulent exudation where no precautions are taken to exclude their admission, and their frequent absence or presence in minute quantities where such precautions are taken, have suggested that through their influence an inflammatory exudation is likely, if not actually compelled, to become purulent.

Whether the microbia or their products are the cause of most suppurative inflammations may be regarded as an open question. It is generally admitted, however, that, as a rule, an inflammation becomes purulent in consequence of the presence of an infective agent; in other words, that most pus is of an infectious origin and possesses infectious attributes. The labors of Lister in insisting upon the exclusion of all possible putrefactive agencies in the treatment of wounds have met with universal approval, and the basis of his treatment remains fixed, although different methods have been devised for its enforcement. His researches, and those stimulated by his work, have resulted in the establishment of principles which affect the whole field of theoretical as well as practical medicine.

Although most pus may be considered as due to the action of a virus introduced from without, and capable of indefinite progressive increase within the body, all pus is not to be regarded as of infectious origin. There are pyrogenetic agencies, like petroleum, turpentine, and croton oil, which, introduced into the body, produce suppurative inflammation without the association of microbia.

A bland pus is usually in a state of beginning putrescence, so that it is only relatively bland, and acquires extreme virulence when long exposed to putrefactive agencies. It is possible that those agencies producing an ichorous pus are the same or different from those present in bland pus. The ichorous exudation contains less corpuscles than bland pus, is more fluid, less opaque, strongly alkaline, of a greenish color, and of offensive odor.

In hemorrhagic inflammation the exudation contains large numbers of red blood-corpuscles. The occurrence of this form is sometimes associated {49} with peculiarities of the cause, as is obvious from the epidemics of hemorrhagic small-pox, measles, scarlatina, and cerebro-spinal meningitis. It is also associated with peculiarities of the individual, as in such epidemics all cases are not equally hemorrhagic, and in scurvy the hemorrhages are attributable to the abnormal conditions to which the sufferers are exposed. Hemorrhagic exudations are also met with in those inflammations of serous surfaces accompanying the outcropping of tubercular and cancerous or sarcomatous growths. In all cases a hemorrhagic exudation represents a grave complication, and when found in serous cavities has a certain diagnostic, as well as prognostic, importance.

Fibrinous inflammations are characterized by the presence in the exudation of considerable quantities of fibrin. As the prevailing theory of the formation of fibrin demands fibrino-plastic as well as fibrinogenous material, both are to be sought for in the exudation. The latter is present in the liquid portion of the exudation; the existence of the former, as well as that of the ferment, is dependent upon the presence of the white blood-corpuscles. The more numerous these, within certain limits, the more abundant the formation of fibrin. As their death appears essential for the fibrinous coagulation, the latter is most constantly met with in those parts of the body where the white blood-corpuscles are quickest separated from influences favoring their life. The farther removed they are from the blood-vessels, the more likely is their early death. Fibrinous exudations are therefore frequent and abundant in cellular and serous (sero-cellular) inflammation of the great serous cavities of the body. The clotted fibrin appears as false membrane lying upon the serous surface, either smooth or rough, tripe-like, or as villosities projecting above the surface, and again as bands, fibrinous adhesions, stretching across the cavity and uniting opposed surfaces.

The frequent occurrence of fibrinous exudations on the mucous membranes of the larynx and trachea, accompanied by the suffocative symptoms known as croup, has led to the use of the term croupous inflammation as synonymous with fibrinous inflammation, and its application to various parts of the body where croupous--i.e. suffocative--symptoms are not in question. Croupous inflammation, when used, is to be considered as an anatomical term, indicating merely the production of fibrin, and, for the avoidance of confusion, it is preferable to substitute fibrinous for croupous when such inflammations are described.

The disease, croup, it is well known, may exist without a croupous--that is, fibrinous--inflammation, as is familiarly recognized in the constant use of the terms spasmodic, membranous, and diphtheritic croup.

Fibrinous inflammation of the mucous membrane of the larger air-passages is much more frequently met with than that of mucous membranes elsewhere, as of the intestines, uterus, and bladder. The pseudo-membranous inflammations of the latter tracts are more commonly the result of the catarrhal and diphtheritic varieties than of the fibrinous form. Fibrinous exudations on mucous surfaces, according to Weigert, can only take place when the epithelium is destroyed. Hence those causes which give rise to the destruction or detachment of the epithelium are alone capable of producing a fibrinous inflammation of mucous membranes, and a fibrinous laryngitis, trachitis, and bronchitis may result from {50} the local application of such irritants as steam or ammonia, as well as occur in the diseases croup and diphtheria.

Fibrinous exudations may also be present within tissues, especially in those whose meshes are wide, provided the essential elements of coagulation are present. The coagulative necrosis of various organs, to be more fully mentioned hereafter, is closely allied to fibrinous clotting, the fibrino-plastic element being derived from the death of the parenchymatous cells of the part.

In the existence of a fibrinous pneumonia the conditions are somewhat analogous to those present in the fibrinous inflammation of serous surfaces and of the areolar connective tissue. There is present an abundantly cellular exudation, held in the place of its origin, the cells undergoing rapid death and surrounded by a wall whose superficial cells resemble in structure, if not in origin, the endothelial cells lining the smaller lymph-spaces of connective tissue, as well as the larger cavities within the same, known as serous cavities.

The diphtheritic inflammation is no more to be confounded with the disease diphtheria than is the fibrinous inflammation with the disease croup. Although diphtheria owes its name to the frequent presence of an apparent membrane, it may be said that the latter is not essential to the existence of the former. Diphtheria, like croup, is an affection in which various exudations may be present, and the anatomical product alone does not suffice in all instances for the recognition of the disease. In croup there may be a swollen mucous membrane, with a slight superficial mucous exudation, or a more abundant exudation of desquamated epithelium and mucus, as well as a fibrinous false membrane. In diphtheria the same varieties of exudation may occur, and in addition the diphtheritic exudation may also be present. The latter, however, is not limited to the disease diphtheria, for its presence is apparent in other mucous membranes than that of the air-passages, and in the pharyngeal mucous membrane in other diseases than diphtheria. A diphtheritic conjunctivitis, enteritis, cystitis, and endometritis are recognized. The cutaneous surfaces of the body may also furnish a diphtheritic exudation. The diphtheritic inflammations of wounds and of variolous eruptions are instances in point.

The characteristics of a diphtheritic inflammation are the presence within the tissues of a clotted exudation, which is associated with a defined swelling and death of the part. The exudation contains not only dead leucocytes and interlacing fibres, but is also provided with abundant granular material, much of which presents the well-known peculiarities of microscopic organisms. The apparent false membrane is thus dead, infiltrated tissue, which may be torn away from the continuous unaffected tissue, leaving a raw, rough surface, but not peeled from a comparatively smooth surface, as in other forms of pseudo-membranous inflammation.

The frequent association of a superficial false membrane, corresponding in area with that of the deeper-seated changes, in which cells and fibres may be present, is to be recognized. The diphtheritic process, however, is localized within, and not upon, the tissues affected. The diphtheritic exudation represents a local death, a necrosis, of the part concerned, and the result has frequently been compared with the death consequent upon the action of a caustic.

{51} The immediate cause of a diphtheritic inflammation is now generally attributed to the action of microbia which enter the tissue from without, and in their growth beneath the surface produce not only the local, but also the remote, constitutional disturbances which are associated with a diphtheritic inflammation. The investigations of Wood and Formad point to ordinary putrefactive organisms as a sufficient cause for the diphtheritic inflammation of diphtheria, while other observers demand a specific organism as the exciting cause. The occurrence of diphtheritic inflammations in various parts of the body, in regions, as the intestine, where putrefactive processes are constantly present, and in the bladder and uterus, where the phenomena of putrefaction are often associated with diphtheritic inflammation, suggest the efficacy of ordinary putrefactive agencies in producing the latter. As all microbia found in putrefaction are not alike, and as the properties of certain, differ from those of others, and as our knowledge of the effects of all is but fragmentary, the characteristics of specific germs for a diphtheritic inflammation of one part of the body, or of all parts of the same, must still be regarded as not proven.

Productive inflammations are those which result in the new formation of tissues. One of the frequent products of inflammation is fibrous tissue, which, at first abundantly cellular, later becomes more vascular, and is finally transformed into a tissue whose fibres predominate over its cells. This formation of a cicatricial tissue demands further recognition when the termination of inflammation is considered.

In a more limited sense certain inflammations are called productive when multiple circumscribed new formations, as cancer, sarcoma, tubercle, and the like, arise in connection with the ordinary products of inflammation. Such new formations are of frequent occurrence in serous membranes, and a tuberculous pericarditis or a cancerous peritonitis, indicates that a growth of tubercles or cancerous nodules has taken place, in addition to a more or less abundant exudation with various proportions of serum fibrin and cells. This association of ordinary and transitory inflammatory products with the formation of more permanent tissues may be found within organs as well as upon surfaces. A tubercular arachnitis or lepto-meningitis presents the various products of an inflammation of the pia mater with an abundant formation of tubercles. In like manner, a tubercular pneumonia, or a tubercular nephritis suggests an association of neoplastic growth and inflammation, in the lung and kidney. Such a relation offers a basis for the theory in favor of the inflammatory origin of tumors, and is, in part at least, a cause for the frequent consideration of tubercles as mere inflammatory products, wholly cellular or cellular and fibrous, subject to the same modifications as take place during the course of ordinary inflammations.

Even if tuberculous and scrofulous inflammations are regarded as inflammatory processes, modified by a specific cause and by peculiarities of the individual, the cancerous and sarcomatous inflammations are still to be considered as representing an association of inflammatory disturbances and specific new formations, the cause of the latter not being the cause of the former. As ordinary inflammations of the regions concerned may take place in the absence of the neoplasms, so may the {52} specific growth appear in the same regions without anatomical or clinical evidence of inflammation.

The classification of inflammation as to its products is supplemented by distinctions drawn with reference to the seat. The exudations may be superficial or deep-seated; they may lie within the cells, parenchyma, of an organ, or within the interstitial tissue of the same.

The product of superficial inflammations may lie on the surface, as in the case of inflamed mucous membranes, or immediately below the surface, as in numerous cutaneous inflammations, of which erysipelas may serve as the type. The term catarrhal, applied to superficial inflammations, carries with it the idea of displacement, flowing, of the exudation. The product of a catarrhal inflammation must be largely liquid, that such a displacement may readily take place, and the catarrhal exudation is chiefly composed of an excess of those elements which are present in the normal, physiological secretion from the membrane concerned. Mucus therefore represents a frequent constituent of the catarrhal exudation, and mucous as well as muco-purulent catarrhs of the gastro-intestinal, bronchial, genito-urinary, and other mucous membranes are recognized. The catarrhal inflammation of the respective membranes usually represents the mildest form, as it demands an intact epithelium, and a ready removal of the inflammatory product.

As the cause of a catarrhal inflammation may occasion a destruction of the epithelium or a necrosis of the mucous membrane, the frequent association of catarrhal with fibrinous or diphtheritic inflammations is obvious. In such cases the clinical importance of the latter varieties gives them the precedence in the designation of the inflammation. The retention of the catarrhal products is the frequent cause of permanent disturbances of a more or less serious nature. These result in part from the mechanical obstruction offered to the function of parts beyond the seat of obstruction, as pulmonary atelectasis; and in part from the changes taking place in the retained product. Purulent otitis media with its dangerous or fatal results, and gangrene of the lung terminating in septic pleurisy, are not infrequent instances of severe disturbances from putrefaction of the retained products of a primarily catarrhal inflammation. A cheesy degeneration of the catarrhal cells leads to a surrounding fibrous, or destructive, inflammation, with a corresponding diminution in the function of the organ affected.

Of the deep-seated varieties of inflammation, that requiring special mention is the phlegmonous form. This runs its course within the less dense fibrous tissue known as the areolar or cellular tissue. The term cellulitis is usually employed by English writers to indicate the seat and nature of the process, and although the use of the term cellular tissue is rapidly becoming obsolete, the convenience of cellulitis favors the retention of the latter name.

The exudation lies within the larger lymph-spaces, and is therefore sometimes designated as the result of a lymphangitis, the deep-seated, wider lymph-spaces being concerned rather than those more superficial. Certain forms of phlegmonous inflammation are of decidedly infectious origin, and, when seated subcutaneously, are known as phlegmonous erysipelas, being thus distinguished from the simple erysipelas, whose seat is defined by the small superficial lymph-spaces of the skin.

{53} Infective forms of cellulitis are also frequently met with in the loose, sub-peritoneal tissue of the pelvis. The infectious element usually proceeds from the uterus, and excites the malignant oedema of the broad ligament, the septic parametritis, or the pelvic cellulitis, according as the lymph-spaces inflamed lie nearer the fundus or cervix, and as the direction of the current is upward toward the spine, or outward toward the sub-peritoneal lymphatics of the pelvic wall.

Parenchymatous inflammation is present when the exudation is taken into the cells of an organ, or when the changes dependent upon inflammation of an organ take place within its functionally important cells. Virchow originally used the term parenchymatous inflammation in contradistinction to secretory inflammation, the changes in the former occurring within the elements of the tissues, while in the latter the exudation made its appearance on the surface of the organ.