DIPHTHERIA (from ______, a skin or membrane), the term applied to an acute infectious disease, which is accompanied by a membranous exudation on a mucous surface, generally on the tonsils and back of the throat or pharynx. Although popularly believed to be a newly dis-covered disease, there is distinct evidence that diphtheria was known to the ancient physicians as a malady of great virulence. Under the name of the Malum. Egyptiacum, Aretaeus in the 2d century gives a minute description of a disease which in all its essential characteristics corresponds to diphtheria. In the 16th, 17th, and 18th centuries epidemics of diphtheria appear to have frequently prevailed in many parts of Europe, particularly in Holland, Spain, Italy, France, as well as in England, and were described by physicians belonging to those countries under various titles; but it is probable that other diseases of a similar nature were included in their descriptions, and no accurate account of this affection had been published till M. Breton-neau of Tours in 1821 laid his celebrated treatise on the subject before the French Academy of Medicine. By him the term Le DiphtMrite was first given to the disease. The subject has since been largely investigated both in Britain and on the Continent, where epidemics more or less extensive have been of common occurrence in recent times ; but while many important facts have been made out regarding the pathology of diphtheria, the real nature of the malady still appears to be undetermined. By some it is regarded as primarily a blood poison, the local mani-festations being secondary and not essential, while others hold, and this is the view now largely maintained by Con-tinental authorities, that diphtheria is at first a local disease, the constitution becoming secondarily affected or poisoned from the local affection. This latter view receives support both from experiments on inoculation of the disease in animals, and from the discovery in the diphtheritic mem-branes and surrounding tissues, as well as in the blood and other fluids of persons suffering from diphtheria, of the lower forms of vegetable organism (bacteria, micrococci, &c), which are supposed to be the infecting agents both in the local affection and in its general constitutional effects. Whether this be the correct explanation of the disease, or whether as is held by many, these organisms are to be looked upon merely as accompaniments or complications of the affection, not present in all cases, the following facts appear to be made out respecting diphtheria :
1. That it is a disease communicable both by infection and by contagion.
2. That grave constitutional disturbance is a constant and prominent symptom of diphtheria.
3. That certain important consequences or, as they are termed, sequehe are apt to follow diphtheria, particularly some forms of paralysis.
These points, moreover, serve to distinguish this disease from croup, which, although in some cases presenting cer-tain features of resemblance to diphtheria, differs from it in being a merely local inflammatory affection. See CROUP.
As already observed, diphtheria has frequently appeared as an epidemic. It is probably more common in a sporadic form (single cases). It is sometimes endemic in certain localities where the hygienic conditions are bad; and there is ample evidence to show that air or water contaminated with decomposing animal matter may readily cause an out-break of diphtheria. The influence of climate, weather, and condition of soil appear to be inappreciable. When the disease has broken out in a dwelling it is apt to spread not merely by direct contagion, but apparently also through the air of apartments, this being notably the case in over-crowded habitations. The contagiousness of diphtheria is very marked, and has unhappily been often exemplified in the case of physicians, who have fallen victims to the disease from inoculation with its morbid products when cauterizing the throats or performing tracheotomy in those suffering from it. Children appear to be on the whole rather more liable to diphtheria than adults; and although the most robust people may be attacked, those whose health is weakened by any cause are specially predisposed. One attack of diphtheria appears to afford no immunity from others.
It must be observed, however, that the mere existence of a sore throat accompanied with some amount of membran-ous exudation does not constitute diphtheria, as is often erroneously supposed by non-medical persons, who are apt to fancy they have had diphtheria several times from having suffered from what is a comparatively simple complaint. The diagnosis can only be reliably made by a medical man.
Cases of diphtheria differ as to their intensity from the mildest forms, which resemble an ordinary catarrhal sore throat, to those of the most severe character (such as the gangrenous form), where the disease is hopelessly intract able from the first.
In general the symptoms at the commencement of an attack of diphtheria are comparatively slight, being those commonly accompanying a cold, viz., chilliness and depres-sion. Sometimes more severe phenomena usher in the attack, such as vomiting and diarrhoea. A slight feeling of uneasiness in the throat is experienced along with some stiffness of the back of the neck. When looked at the throat appears reddened and somewhat swollen, particularly in the neighbourhood of the tonsils, the soft palate, and upper part of pharynx, while along with this there is tenderness and swelling of the glands at the angles of the jaws. The affection of the throat spreads rapidly, and soon the characteristic exudation appears on the inflamed surface in the form of greyish-white specks or patches, in-creasing in extent and thickness until a yellowish-looking false membrane is formed. This deposit is firmly adherent to the mucous membrane beneath or incorporated with it, and if removed leaves a raw, bleeding, ulcerated surface, upon which it is reproduced in a short period. The appear ance of the exudation has been compared to wet parchment or washed leather, and it is more or less dense in texture. It may cover the whole of the back of the throat, the cavity of the mouth, and the posterior nares, and spread downwards into the air passages on the one hand and into the alimen-tary canal on the other, while any wound on the surface of the body is liable to become covered with it. This mem-brane is apt to be detached spontaneously, and as it loosens it becomes decomposed, giving a most offensive and characteristic odour to the breath. There is pain and difficulty in swallowing, but unless the disease has affected the larynx no affection of the breathing. The voice acquires a snuffling character. When the disease invades the posterior nares an acrid, fetid discharge, and sometimes also copious bleeding, takes place from the nostrils. Along with these local phenomena there is evidence of constitutional disturbance of the most severe character. There may be no great amount of fever, but there is marked depression and loss of strength. The pulse becomes small and frequent, the countenance pale, the swelling of the glands of the neck increases, which, along with the presence of albumen in the urine, testifies to a condition of blood poisoning. Unless favourable symptoms emerge death takes place within three or four days or sooner, either from the rapid extension of the false membrane into the air passage, giving rise to asphyxia, or from a condition of general collapse, which is sometimes remarkably sudden. In cases of recovery the change for the better is marked by an arrest in the extension of the false mem-brane, the detachment and expectoration of that already formed, and the healing of the ulcerated mucous mem-brane beneath. Along with this there is a general im-provement in the symptoms, the power of swallowing returns, and the strength gradually increases, while the glandular enlargement of the neck diminishes, and the albumen disappears from the urine. Recovery, however, is generally slow, and it is many weiiks before full con-valescence is established. Even, however, where diphtheria ends thus favourably, the peculiar sequelae already mentioned are apt to follow, generally within a period of two or three weeks after all the local evidence of the disease has disappeared. These secondary affections may occur after mild as well as after severe attacks, and they are principally in the form of paralysis affecting the soft palate and pharynx, causing difficulty in swallowing with regurgitation of food through the nose, and giving a peculiar nasal character to the voice. There are, however, other forms of paralysis occurring after diphtheria, especi-ally that effecting the muscles of the eye, which produces a loss of the powei of accommodation and consequent impairment of vision. There may be, besides, paralysis of both legs, and occasionally also of one side of the body (hemiplegia). These symptoms, however, after continuing for a variable length of time, almost always ultimately disappear.
In the treatment of diphtheria regard must be had both to the local and general nature of the disease. Difference of opinion exists among physicians as to the utility of topical applications in the form of caustics applied to the affected parts, some attaching great importance to their use as tending to arrest the progress of the disease, while others hold that the irritation so produced favours the spread of the false membranes. Probably at the outset, when the local manifestations are but slight, the use of such a caustic as nitrate of silver, either in the solid form or in strong solution, may be of service ; but after any con-siderable surface has been invaded by the false membrane little good, it is to be feared, can be done in this way. The forcible removal of the false membrane is generally con-demned, as by this means a raw bleeding surface is left, upon which the deposit is reproduced with great rapidity. The exudation, however, tends to be cast off spontaneously by a process of suppuration, and, as favouring this, and at the same time acting as a soothing remedy, the inhalation of steam is recommended. The employment, in the form of spray or of washes or gargles, of solutions of carbolic acid, Condy's fluid, perchloride of iron, chlorine water, or chlorate of potash, is valuable in the way of disinfecting the parts, and subduing the fetid exhalations which are always, present. When the disease has spread into the larynx and the breathing is embarrassed, an emetic may be of use in aiding the expulsion of the false membrane. It is, however, in great measure to the constitutional treat-ment that the physician's attention must be directed in diphtheria. The effect of the disease upon the patient's strength is so marked that from the very beginning there is an urgent demand for strong nourishment, which should be freely administered in the form of milk, soup, &c, as long as there exists the power of swallowing, and when this fails nutrient enemata should be resorted to. Large doses of quinine and of the tincture of the perchloride of iron are recommended, and stimulants will in almost all cases be called for from an early period. The question of tracheo-tomy has to be considered when the false membrane has spread into the air passages and threatens death by asphyxia; and although the operation in such circum-stances affords but a feeble chance of success, the cases of recovery by this means have been sufficiently numerous to justify its employment as a last resort. The paralysis which follows diphtheria usually yields in the course of time to tonics and good nourishment.
It should be mentioned that in all cases of diphtheria means should be taken by isolation of the patient and the use of disinfectants to prevent as far as possible the spread of the disease in a household ; while the attendants ought to be scrupulously careful to avoid inoculation with the products of the disease, and should frequently use gargles of some of those'substances above mentioned. (J. O. A.)