Inflammatory action is seldom so intense as to terminate in death of the part, unless the power of that part has been diminished by previous local or constitutional disease, or by injury; and the inflammation preceding gangrene is all along attended by symptoms of so well-marked debility, both local and general, that it is frequently designated the Inflammatio Debilis. Of inflammatory affections, the erysipelatous most frequently terminates in gangrene; in other words, the power of resisting incited action is not so great in the cellular tissue and skin as in other parts of the body.
The period at which the symptoms of gangrene appear after an accident varies, in general, according to the severity of the injury. As was already observed, the part may be immediately deprived of its vitality—if not, symptoms of gangrene sometimes appear within a few hours after reaction has taken place; while in other cases, tension, pain, and heat occur, and may continue for a longer or shorter time, according to the degree of power remaining in the part. Tension often exists to a great extent after severe injuries, from extravasation of blood or serum; the functions of the vessels are thereby interrupted, and gangrene is inevitable. As the action proceeds, the pain and heat often subside—the parts become flaccid—dark-coloured serum is effused beneath the cuticle, forming what are termed Phlyctenæ—the skin becomes dull and livid—dark streaks extend along the limb, perhaps from the colouring matter of the blood transuding, as in commencing putrefaction in the dead body—air is effused into the subcutaneous cellular tissue, causing a sense of crepitation when pressed by the finger—sloughs form, either black or of an ash colour—and the gangrene involves a greater or less extent of the limb. The mortification is here represented as attacking a limb that had suffered from compound fracture. The dark part around and above the protruded bone was in a state of sphacelus. The dorsum of the foot and the integument towards the knee were only gangrenous. The patient was advanced in life, and the state of the constitution such as to induce a belief that there was a predisposition to mortification. The removal of the limb was, under the circumstances, reckoned inexpedient. In some instances, the mortification is most towards the surface; in others, it is chiefly amongst the deeply seated parts. Sudden cessation of pain is generally regarded as an unequivocal sign of the occurrence of gangrene, especially in the internal viscera; but it not unfrequently happens that the painful sensations suddenly cease, whilst no gangrene supervenes, and that a part mortifies, whilst the pain continues but little abated.
In compound fractures, dislocations, or severe bruises of the soft parts, dark-coloured, prominent points occasionally appear, in consequence of the effusion of bloody serum beneath the cuticle; in these, however, the fluid is speedily absorbed, and the surface resumes its natural aspect, the cuticle exfoliating and being reproduced; and it is of consequence to know their real nature, for, if mistaken for the gangrenous phlyctenæ, the inexperienced practitioner may be alarmed, and, consequently, have recourse to very injudicious practice.
When the process of gangrene is checked, the skin immediately beyond the mortified part becomes of a brighter hue, and is affected by a more healthy species of inflammation, which ultimately terminates in ulceration, with purulent discharge, and thereby forms what is called the line of demarcation between the dead and the living parts; the process, commencing in the integuments, gradually extends to the deeply seated parts, so that the mortified portion is ultimately attached to the living merely through the medium of bone or ligament. Arteries appear more than any other texture to resist sloughing; and those leading to a mortified part are found contracted and filled with coagulated blood, so that the spontaneous separation of the sloughs, and even incisions for their removal, made in sound parts, are followed by little or no bleeding. This salutary change in the arteries may be accounted for by supposing, that the inflammatory action which leads to the separation of the dead substance from the living affects the arteries at that point as well as the other structures, causing adhesion of their internal surface, and obliteration of their cavities; and the natural result is, that the calibre of the artery above the obliterated point gradually diminishes in size, and the blood coagulates up to the nearest collateral branch: but in consequence of extension of the inflammatory action, the collateral branches may also be obliterated to a considerable extent upwards, and thus the contraction and coagulation in the larger trunk will also extend in proportion. Besides, before the line of separation has commenced, arteries cannot transmit their contents into the sphacelated part, any more than into an extraneous body; so that the circulation of the blood in them is as effectually obstructed as if a ligature were tightly applied; in this way, also, the contraction and coagulation may be accounted for.
Mortification is accompanied with great anxiety; coldness and clamminess of the face and extremities; weak, irregular, and hurried circulation; quick, short breathing; a cadaverous expression of countenance; hiccup (which, however, often occurs in very slight sloughing, or when no sloughing has taken place, in external or internal inflammations, extravasations, &c.); by diarrhœa, vomiting, and in hopeless cases, more especially of traumatic gangrene, by delirium and coma; in fact, almost all the symptoms of severe constitutional irritation are more or less fully developed. In some cases, the patients are restless and unmanageable; in others, low and dejected. The disease often proceeds with fearful rapidity to a fatal termination, the patient becoming comatose from effusion within the cranium; but in other instances, in which the vigour of the constitution is greater, and the extent of mischief less, the system bears up under the affection, and a separation is effected between the dead and living parts. The danger is in general to be estimated by a consideration of the size and importance of the part, and of the age and constitution. The destructive consequences of sphacelus arise both from a local and general cause; for the mere application of putrid animal substance to a part still alive—the infiltration, for instance, of dark serosity into the cellular tissue in the course of a limb—causes a sort of inflammation attended with symptoms of diminished power, and followed by constitutional disturbance; whilst the ultimate extinction of life may be imputed to the effect produced on the system by the part previously to its becoming sphacelated, and to the sympathy between the system and the parts which are left in a weak and moribund condition, and which seem endowed with a disposition to extend the disease.
In the treatment of mortification, no one would think of using any means, local or general, so long as the cause remained; and it therefore must in the first place be removed, otherwise the mischief may speedily become irreparable; thus, a stricture must be divided, irritating fluids evacuated, foreign bodies extracted, &c.
In chronic gangrene the cause is constitutional, and the means employed must be directed accordingly. In general, the power of the constitution requires support, though, in cases where much fever is present, it may often be necessary to keep the patient on low diet: exhibit salines and mild purgatives in the first instance. The effects of food should be attentively watched, and its quantity increased or diminished accordingly. On the subsidence of the fever, and when sphacelus has occurred, wine and animal food must be given abundantly. Stimulants, strictly so called, are not admissible until the line of separation be formed, and their exhibition must then be regulated by the circumstances of the case. Opium and other anodynes are found necessary during the progress of the disease, to allay irritation and produce sleep; opium has been recommended on very high authority, that of Mr. Pott, in mortification of the lower limbs. The bowels must be attended to. Peruvian bark was at one time supposed to be a specific in this disease, but experience has not born out the opinion; it seldom agrees in substance, and the decoction, with or without the compound tincture or sulphate of quina, will be found much more useful in supporting the power and tone of the digestive organs. After the line of separation has been formed, and not till then, the surgeon may interfere, and assist nature in her work, dividing the exposed bones or ligaments by which the dead parts still adhere to the living; or he may perform amputation immediately below the line of demarcation. Amputation in the sound parts cannot be recommended: for vitality is impaired throughout the system, and more particularly near and above the line of demarcation, where, though the structure seems entire, yet the incisions are made in parts really diseased, and which would almost certainly and speedily mortify. In fact, amputation above the line of separation, in whatever way performed, is seldom if ever productive of advantage in spontaneous gangrene.
In order to prevent the occurrence of gangrene after exposure to intense cold, the frigid part must be cautiously and slowly restored to its natural temperature; first by being either placed in very cold water, or rubbed with snow; afterwards, by the degree of warmth in the applications, and surrounding atmosphere, being gradually increased.
In acute gangrene, and in robust constitutions, when the affection arises from over-action, abstraction of blood is had recourse to with marked advantage. In some cases it may be employed, but with due caution, even after sphacelus to a slight extent has occurred. In gangrene, purging and bleeding must not be had recourse to but with the greatest circumspection; for it ought always to be remembered, that however strongly they may be indicated, the time is not far distant when they will be totally inadmissible, and when the weakening effects of depletion will prove highly prejudicial, particularly in cases where the mischief is proceeding rapidly.