Phlebitis (Inflammation Of The Coats Of The Veins) is the primary disease, although it may be owing to various causes, while every anomaly of the blood within the inflamed tube of the vessel, and still more, perhaps, beyond that spot, such, for instance, as the coagulation of the blood within the inflamed vessel, is a secondary phenomenon, depending upon the product of the inflammation.

This phlebitis is very frequent as a primary disease, and arises from the most various injuries, as cuts or thrusts, affecting either the vein alone, or, conjointly with it, other soft and firm parts; from contusions and displacements of different soft parts including the vein; or from many forms of surgical or medical maltreatment of wounds of the veins. This disease so far depends upon the epidemic constitution, that it is of extremely frequent occurrence at certain periods, with or without the concurrence of these favoring circumstances. This disease may also be of a secondary character, and in that case it is derived either from inflamed contiguous structures - as, for instance, the inflammation of the veins in the neighborhood of abscesses, phlebitis from inflamed carious bones, etc, - or is of a metastatic nature, as the phlebitis which occurs in the course of many different acute febrile affections, and as one of their sequelae.

2. At other times the coagulation of the diseased mass of the blood within the tube of some one vein is the primary, and indeed the special occurrence, which gives rise, from reaction as it were, to inflammation of the coats of the veins - phlebitis. This disease is then a dependent, secondary affection, of subordinate importance. Such a form of phlebitis always consists in the establishment of a disease of the blood, which is either of a spontaneous character, or depending upon the absorption of different deleterious substances, such as inflammatory products originating either within or external to the vascular system. It constitutes the most frequent of what are termed metastases, especially if we include the process of the coagulation of blood in the capillaries - the so-called capillary phlebitis.

This distinction of character, which has hitherto not been sufficiently regarded or properly understood, is of the greatest practical importance and interest, since it affords a clue to the right comprehension of the significance of phlebitis in individual cases, and thus contributes to throw light on many points in the history of phlebitis which had either remained entirely obscure, or had been explained in a wholly irrational manner. We shall always indicate this latter form of phlebitis as that which depends upon coagulation of the blood.

A. The following are the anatomical indications of (acute) phlebitis:

1. Injection And Redness Of The Cellular Coat Of The Vein

Injection And Redness Of The Cellular Coat Of The Vein, in different degrees and shades of color. The cellular coat is very commonly intersected by varicose vessels, and is at the same time of a bluish-red color, which, however, experiences various modifications by the infiltration of inflammatory products into its tissue. The latter membrane very frequently presents a darkish-red, mottled or streaked appearance, in consequence of slight extravasations.

2. Infiltration Of The Cellular Coat

Infiltration Of The Cellular Coat, with a serous, sero-fibrinous, partially solidifying, grayish, gray or yellowish-red moisture, and bulging of the coat; the infiltration is very commonly associated with a thin sero-purulent, or thick purulent moisture and with bulging, whilst more or less circumscribed abscesses occur in the interior of the vessel.

The neighboring cellular tissue participates, in various degrees, in the process, although, generally speaking, in proportion to its vicinity to the seat of the disease; the tissue becomes vascularized, infiltrated, and swollen, and the vein becomes then fixed or imbedded in it. We also very often observe circumscribed abscesses, together with diffused purulent infiltration at some distance from the vein.

3. Injection And Redness

Injection And Redness, as well as the other discolorations produced by the infiltration of various products, extend into the circular fibrous coat of the vein. The latter coat appears to be vascularized; but more frequently the injection and redness of the tissue are already obliterated. It then presents a grayish-yellow faded appearance, and is discolored at different points by imbibition from within, or from the contiguous extravasations in the cellular coat, or is mottled red by small extravasations within its own tissue; it is, moreover, unusually succulent, and is swollen. In phlebitis with purulent exudation, it is most distinctly infiltrated with the purulent or sero-purulent fluid.

4. The Inner Coat Of The Vessel

The Inner Coat Of The Vessel presents a dirty-white appearance, or is colored red, violet, brown, or even green, by the imbibition of haematin from its interior, or from hemorrhagic exudations into its tissue. It is swollen; the inner surface is devoid of lustre, is dull, felt-like, and wrinkled. When purulent exudation is present, it is more especially of a pale yellowish color, succulent and lustreless.

5. All The Coats Of The Vein Are Relaxed

In addition to these alterations, all the coats of the vein are relaxed in their texture, and admit very readily of being torn, and separated from one another. In some cases the strata composing the inner coat (together with the valves) are detached from the circular fibrous coat, and even cast off in the form of a tube; and this is of very general occurrence in the more intense forms of phlebitis with purulent exudation. - In these cases, the inner coat, which is thrown off in the form of a tube, may be the more readily mistaken on a superficial examination for a tubular exudation, when its tissue admits of being readily torn, and it has been colored yellow by the imbibition of pus.

6. The Vein

The Vein appears to be dilated and paralyzed; its tube is generally either filled by a plug of blood, which either resembles a recent coagulum, or has entered into different metamorphoses, or is filled with the product of the process (the exudation), more especially pus. The formation and significance of the above-named coagulum are intimately connected with the actual process of exudation, as will be seen by the following remarks:

7. Exudation

The exudations deposited in the texture of the venous coats, and in the contiguous tissues surrounding the vein (its cellular bed), have already been in part considered, both in reference to their bulk and nature. A far more important class of exudations are those which are deposited on the inner free surface of the vein (within the vein), and which, owing to their absorption into the blood, and the infection to tvhich they may give rise, impart to phlebitis the dangerous character that renders it so formidable a disease. The general disease arising from these conditions, together with its intensity and character, depends upon the nature of the exudation, and also upon certain accidental circumstances, which we now proceed to consider.

A. The Exudation

The Exudation may vary very considerably, both in reference to its physical properties and its internal composition. A direct anatomical demonstration of the exudation itself, either in reference to the originally inconsiderable quantity in which it appears, to its absorption into the blood, or still more in regard to the evidence of its original and special quality, is very difficult or even impossible. We would especially notice:

The so-called plastic exudation, capable of undergoing a metamorphosis of tissue, which, in rare cases, occurs in an appreciable quantity as a flocculent, soft, or consistent membranous coagulum on the inner surface of the vessel, or adhering to the fibrinous plug which fills the vein. The quantity of exuded serum originally contained within it never admits of being detected, as it is absorbed by the blood at the moment of its exudation, together with the greater portion of its coagulable matter.

The purulent and ichorous exudation, which is a very frequent product of phlebitis, is generally secreted in such abundance, that it may be easily recognized, even in those cases in which the blood has coagulated within the vessel. It very commonly expels the blood entirely from the vein, which is then completely filled with pure pus or ichor, the product of the process of exudation. We, moreover, here meet with exudations of a fibrinous, purulent product deposited under the lining membrane of the vessel, in the form of islands or large patches, exhibiting diffused, purulent, ichorous infiltration of the venous coats, together with discoloration, loosening, and a high degree of lacerability and detachment of the strata composing the lining membrane, in the form of a lax, lacerable, disintegrating fusing cylinder, which might easily be mistaken for a tubular exudation.

Are any of these exudations of a hoemiorrhagic or a tuberculous character? In many instances, indeed, we observe a red, brownish or violet-red, or chocolate-brown coloration of the exudation on the inner surface of the vessel, together with a hemorrhagic suffusion of the coats of the vein, and centres of hemorrhagic exudations in the neighborhood of the vessel.

We have never observed a tuberculizing exudation, or even one whose nature led us to suspect a tuberculous character, on the inner surface of the vein. (See our subsequent remarks on Tuberculosis).

B. The Coagulation Of The Blood In The Inflamed Vessel

The Coagulation Of The Blood In The Inflamed Vessel, or the formation of a fibrinous plug, which is most intimately connected with the deposition of an exudation upon the inner surface of the vein, and with its absorption into the blood, is a phenomenon of the greatest and most varied interest. It arises from the contact of the blood with the products of inflammation. The subject has been already generally considered under Diseases of the Blood, and will therefore be noticed here only in as far as is indispensably necessary towards the right comprehension of phlebitis.

Phlebitis, if we may judge from appearances after death, very rarely occurs without a simultaneous coagulation of the blood in the inflamed vein.

The inflamed vein is very commonly filled by a cylindrical fibrinous plug, which, according to circumstances, is either single or ramified, and terminates conically at both extremities.

In phlebitis having a purulent exudation, the coagulum is either present in the above-described form, or is disintegrated, and blended with the purulent product in the form of loose, friable detritus; or, finally, there may be no trace of its presence, in which case the vein is entirely filled by copiously exuded pure pus.