When we undertake the consideration of those features of iodine therapy which have to do with its adaptability to definite remedial ends, we enter upon a field of thought that may take several forms.
We are concerned, in this treatise, only with matter relating to regional, topical, or local applications of the agent under discussion, and we can well begin the consideration with the identification of the agent itself and the different forms under which it is most commonly used. For all practical purposes, we can confine the discussion of the agent itself to that of the four forms, or preparations, of iodine in almost universal use by practitioners of veterinary medicine and surgery. When, in veterinary medicine, allusion is made to iodine, it is almost, without exception, to one of the following preparations:
Only in rare cases, and then under specific reference, is iodine used in other forms, or in its elemental state, in veterinary medicine. Iodine is a very active agent, chemically as well as therapeutically, and is not readily compatible with other agents. It is for this reason, that combinations of iodine with other drugs and chemicals are not common, and therein lies a distinction for iodine that not many other therapeutic agents can claim; namely, that beneficial effects resulting from iodine medication are almost, without question, due to it alone; it is hardly ever applied in combination with synergists which might obscure the activity of individual ingredients.
This remarkable therapeutic activity of iodine is such that, when properly applied in some of its forms, its presence can be demonstrated in the underlying tissues. After prolonged courses of topical application, its action is occasionally appreciated, both subjectively and objectively, in the evidence of more or less clearly defined constitutional or systemic indications of its presence within the animal organism.
From this, it is apparent that, in iodine preparations of a particular class, we have an agent whose topical remedial effects are, in some slight measure, due to systemic action; in part at least, this action being the effect of great physiological activity exerted in the limited area of its topical application. In some degree this activity of certain preparations of iodine can be explained by reference to the chemical properties inherent in iodine as elemental matter, and in its well-known affinity for certain elemental constituents of the tissues of the animal organism.
The foregoing throws some light on the therapeutic accomplishments of iodine preparations, when topically applied, and, to a certain extent, explains its modus operandi in a physiological sense—an understanding somewhat essential from an ethical standpoint. The old theory, which would ascribe to an increase in function of the regional lymphatic glands all the agreeable therapeutic effects of local iodine applications, does not cover enough ground; it is only when we amplify this theory, with the assumption of the considerations aired in the foregoing paragraphs, that we find it possible to attain a clear understanding of the physiological action of iodine preparations applied regionally.
The Clinical Aims for topical therapy are to be classified as follows:
Under these three heads, we further sub-classify the actual clinical conditions, which are indicated, into the following:
Under 1. Surgical preparatory technique.
Under 2. Acute pathological conditions, in the corrections of which topical applications of iodine preparations are used as an adjunct to internal medication with other agents.
Under 3. Chronic pathological conditions, in which one or more of various iodine preparations, locally applied, constitutes the entire treatment.
This classification and sub-classification is important and essential when we endeavor to make our use of iodine conform to ethical standards; it is also very essential to the attainment of certain therapeutic ends in actual practice.
The exhaustive pre-operative washing and scrubbing of the integument, that veterinary practitioners applied to their surgical patients in years past, has given way almost entirely to iodine painting. Even those surgeons who still adhere to the scrubbing and washing of the parts about to be incised, complete the process with an application of iodine thereafter.
An application of iodine to the skin covering the region that is about to be invaded by the knife of the surgeon, has been found much more efficacious and much more reliable than has the washing and the scrubbing with antiseptic solutions, soaps and other agents. Not only this, but it has also greatly simplified and shortened an otherwise tedious, prolonged and sloppy technique. Whereas, the surgeon formerly spent from fifteen minutes to half an hour scrubbing and washing the field of operation, he now applies a few coats of iodine tincture—a few strokes of the swab or brush—and it is done.
This simplified technique has the added advantage of the total elimination of basins, brushes, and sponges for use in the preliminary stages of an operation, as well as the agreeable absence of the wet, sloppy field that inevitably resulted from the use of the older method in veterinary practice. Besides, it spares the patient in more ways than one, especially in the cold months of the year when, in a veterinary practice, operations frequently have to be performed in cold stables, or even in the open.
While the application of tincture of iodine gives ample protection from skin infection in surgical operations, there are a few things to be observed that have to do with making the application correctly. First, in veterinary patients, the hair must be clipped off and the area shaved clean. The area clipped and shaved should be slightly greater in extent than the field actually to be invaded by the knife. When the clipping and shaving have been done, the area should be lightly brushed with a stiff, dry brush, in order to remove dandruff and scurf.
The second—and the most important—point is that the surface that is to be painted with the tincture of iodine be perfectly dry. In the event that the area to be painted should contain a deposit of filth, oily or greasy in nature, this should first be removed by swabbing and wiping with gauze or cotton saturated with gasoline, benzine or ether; these remove oily, greasy or fatty filth and evaporate quickly, leaving the area perfectly dry and clean. Washing with watery solutions, previous to the iodine application, is not recommended under any conditions.
When the area has been clipped, shaved, freed from grease or other filth, and then allowed to become perfectly dry, the tincture of iodine is applied liberally with a soft brush, or with a cotton swab. This is allowed to dry for a minute or two; another application is then made directly on top of the first one, allowed to evaporate to dryness, and the field is ready for the incision.
As iodine readily attacks metals, and spoils the plating on instruments, no instrument should be allowed to come in contact with the painted area while it is still moist; neither should the iodine be used for disinfecting purposes on any utensils or apparatus made of metal. The fact that the iodine may injure instruments can not be considered in the light of a disadvantage, if the above precautions are taken.
Another practice that has come to be recognized quite generally among surgeons is that of painting the edges of the surgical wound with pure tincture of iodine just before the wound is to be closed with sutures. Whether this is good practice, on general principles, is a matter that is open to debate. If the painting is done carefully, so that a pool of iodine tincture is not formed by the surplus gathering by gravitation into the deeper recesses of the wound, this may be considered good practice. On the whole, however, it would appear that the iodine could act, in many instances, as an undesirable irritant when it comes in contact with delicate, freshly incised tissues.
As the object, in modern surgery, is to eliminate all things, even the slightest, that may hinder prompt repair and smooth healing of the invaded tissues, the presence of such an active agent as pure tincture of iodine in a surgical wound may be looked upon as interfering with the carrying out of that object.
On the other hand, in surgical wounds of an already infected character in which primary union would be out of the question, the application of pure tincture of iodine, in liberal amounts, can not be too highly endorsed.
The latter statement applies, with even greater force, to all wounds of an accidental character in the fleshy portions of the anatomy.
It is also the practice of many veterinary surgeons to apply pure tincture of iodine to the wound after the sutures have been put into place. This is a very satisfactory practice, if the painting is done gently and not too freely. An excess of the tincture of iodine—if the wound edges have not been coapted perfectly—may result in cause for stitch abscess when a considerable amount of the iodine becomes pocketed in some part of the wound under the line of suture.
In certain animals, whose skins are very tender, the local application of pure tincture of iodine, previous to surgical incision, is followed, in a few days, by slight peeling of the integument. This is so rare an occurrence, however, and of so little consequence, that it need not be considered, and can not be looked upon as a drawback to this otherwise salutary practice.
Aside from its use in the preparation of the surgical field, tincture of iodine is also used, in a prophylactic sense, to prepare the skin—in a similar manner—for the entrance of the hypodermic needle whenever a subcutaneous injection is to be made. It is not practical, nor necessary, in this instance, to shave away the hair; the site that has been selected for the needle puncture is merely painted liberally with the iodine. As in the case of a surgical incision area, so also here, the parts to which the application is made must be perfectly dry.
Iodine preparations of various forms are very commonly used topically as an adjunctive treatment to internal medication in the treatment of a number of acute pathological conditions in veterinary patients. The object in adding local iodine applications to the handling of such conditions is varied. In some cases, the object of the practitioner is to hasten the correction of certain well-marked local manifestations of the disease with which the patient is afflicted. In other instances, the aim of the practitioner is toward the prevention of these local manifestations. Occasionally, in a certain type of pathological conditions, the practitioner intends, by the use of topical iodine applications, to enhance the internal treatment being aimed at symptoms whose entire nature is local in character and confined to a very limited portion of the anatomy.
In every case coming under this sub-classification, the effect that the iodine applications have—the only effect that they are able to accomplish—is one of amelioration; they can have no direct curative effect here. While the various conditions that are included under this head will be fully discussed in following chapters, I will point to the use of topical iodine medication in the handling of a case of parotitis as an illustration. While regional applications of iodine are the rule, in the handling of cases of this affection in veterinary patients, no one at all versed in the condition as it occurs in practice would give the credit of ultimate cure to the iodine applications. But all will admit readily that, while the internal treatment indicated by the pathology of the condition is correcting the lesion per se, the regional applications of iodine do contribute materially to a smooth termination of the case in that they do, without question, lessen the possibility of abscess formation, relieve the pain, and hasten resolution.
The conditions included under this heading form, in great part, that class of cases to which reference was made in the beginning of this treatise, namely, those in which iodine treatment is largely used under circumstances and in conditions that lack almost every scientific indication for its application. Yet, it is in these very conditions, and under these very circumstances, that topical applications of iodine are frequently most salutary in effect. And this effect is enhanced to the degree, as will be pointed out later, to which the practitioner becomes adept in the selection of the proper form or preparation of iodine for the particular case in hand.
It is in the correction of chronic pathological conditions, that iodine therapy finds its greatest field in the practice of veterinary medicine and surgery. It is in chronic pathological conditions, that iodine, in various forms, and with various modes of application, so forcibly demonstrates its therapeutic work, for it is here that iodine is often the only agent used in the handling of the case, thus constituting the entire treatment. Under these circumstances, it is never a difficult matter to decide as to the value of the treatment or the activity of the agent used.
Were there no other means of demonstrating the fact that iodine, in some of its forms, arouses the animal organism to the end, and in the direction, of marked efforts at regional cure of various pathological states, we would have evidence of ample weight to convince us of this in the results that we daily get with its application in a general practice.
There is hardly any therapeutic result from which the practising veterinarian derives more professional satisfaction than he does from the sure, gradual effect of properly selected and correctly applied iodine preparations in chronic pathological conditions of the articulations, from the speedy and specific effect of others in certain skin diseases, and from the almost miraculous cure of certain localized infections when the proper iodine medication is applied in these.
So sure are the effects of iodine, in a curative way, in certain diseased conditions among domestic animals, that it has value in this regard from a diagnostic standpoint. Given a case apparently of this type for handling, the practitioner can be assured that he has erred in his diagnosis if iodine, in proper preparation and correct application, does not effect a cure. To illustrate this, I need only refer to that diseased condition of the skin commonly termed “ring worm.”
It is nothing unusual, in a veterinary practice, to see the curative effects of iodine applications demonstrated in certain chronic conditions, of the articulations for instance, after various other means of handling, even including surgical interference, had failed to effect the desired result. In not a few of such conditions, iodine applications, in some form, are prescribed as a sort of “last resort” treatment, even against the hopes of either client or practitioner, for the accomplishment of anything in the way of benefit.
Almost any practitioner of veterinary medicine, with whom you may care to discuss the matter, can point to case after case, in his own practice, in which a spavin, or a ring-bone, that had been cauterized or otherwise operated upon with failure, had yielded to a course of topical iodine applications. In some instances, a cure of this sort causes a practitioner to lose faith in operative measures for the correction of the conditions in question. Usually, however, it impresses upon him, with added force, the thought that he has not fully acquired the knack—either along practical or scientific lines—to select his cases properly. Could he be sure that a given case would yield to applications of iodine preparations, he would much prefer to treat it that way; but he is not often sure. He has learned that there are certain cases, although to all appearances, as far as he is able to tell, not differing from other cases of the same nature, will yield to actual cautery; he has learned, also, that certain cases will yield to local applications of certain iodine preparations. But he finds it difficult to select these cases for the respective forms of treatment in the general run of his practice. That he may be better able to serve his clients, and that he may even more highly appreciate the therapeutic worth of iodine in some of its forms of preparation, I have made some clinical observations, in my own practice, which I shall record in the following chapters, and which, I believe, will help to solve this problem for him. While it is not possible to pick out every case in which iodine applications will give the desired result, it is not an exceptionally difficult matter to select the great majority. It is the opinion of most veterinary practitioners, who have the ethics of their profession at heart, that the treatment of certain well-known pathological conditions of the articulations, by means of the actual cautery, is one of the most disagreeable features of a veterinary practice. It is one of the things that most veterinary practitioners are trying to get away from; it smacks more of quackery and dark-aged farriery than anything else that the veterinarian is obliged to do. When, on top of this, we view this form of treatment from the angle of the humanitarian, we fail to understand why otherwise able and enlightened practitioners will resort to it under any conditions. True, there are apparently a few forms—a very few—of equine lameness that will yield to no other form of treatment. Note, I have said apparently there are some. I believe, in fact, that any case of lameness located in an articulation is curable, if it is curable at all, by means other than burning the area with a red-hot iron. While most of us, in practice, do fire cases of articulation lameness, I believe that we do so for the reason that frequently it is for us the easiest way to terminate the conditions connected with the case. And I further believe that every time we resort to the actual cautery, for the correction of a lameness in an articulation, we admit, in the fact that we do so resort, that we do not fully understand the condition we are attempting to cure. This belief is the result of actual contact with ample clinical material and the observations made in actual practice covering a period of time extending over more than fifteen years.
Other chronic pathological conditions, in which iodine applications are frequently serviceable, are various new-growths in the integument, underlying tissues, and in the glandular tissue near the body surface. It is often possible to accomplish, with topical iodine applications, results in these conditions which could only be equalled by surgical interference of much more costly and dangerous character. Iodine applications are at times resorted to in such conditions as these, to obviate the scar formation that might result from a surgical operation. At other times, resort is had to iodine on account of such objections to surgical interference as cost, danger to the patient’s life, protracted period of convalescence, or other equally reasonable objections.
In the effects that are obtained from the local applications of iodine preparations, in chronic pathological conditions, these preparations act not only in a palliative or ameliorative sense, but literally in a curative manner. They accomplish, in these conditions, solely and wholly through their own activity, the removal of the condition and the correction of the respective abnormalities. While, in some of the conditions under discussion, the desired result is attained only after very prolonged treatment with iodine, the condition is usually of such a character that neither the owner of the animal nor the attending veterinarian is averse to lending the time consumed. In other of these conditions, the desired result comes very promptly, at times with a rapidity that causes astonishment. In all cases yielding to topical iodine therapy, sufficient evidence of the beneficial effect derived is discernible with sufficient promptness to encourage the continuance of the treatment.