ARE DIPHTHERITIC AND PSEUDO-MEMBRANOUS CROUP IDENTICAL OR DISTINCT AFFECTIONS?

BY

J. LEWIS SMITH, M.D.,

PHYSICIAN TO THE INFANT HOSPITAL, NEW YORK, ETC.

THE term Pseudo-membranous Croup, Membranous Croup, or, for brevity, Croup, is applied to a sporadic inflammation of the larynx, which is accompanied by the formation of a pseudo-membrane upon the laryngeal surface. It is attended by no symptoms. except such as are referable to the local disease, and it destroys life by the mechanical effect of the exudation. Croup is universal; Steiner says, "Croup extends over the whole world, but strikingly diminishes in frequency, according to A. Hirsch, as we pass from the higher latitudes to the tropics." Therefore nearly every physician in general practice meets cases from time to time. My present purpose is to consider the relation of this malady to an inflammation of the same parts, which is accompanied by a similar exudation and with similar local symptoms, but which we know to be a form of, or a manifestation of, a contagious and epidemic disease, namely, diphtheria.

There are two theories regarding the relation to each other of croup and diphtheritic laryngitis. The first is that they are entirely distinct, that the one is a simple, non-specific inflammation, not capable of reproducing itself, while the other is specific and contagious; that, therefore, they sustain to each other, as one of our writers has well said, a similar relation to that which exists between ordinary metritis and the metritis of puerperal fever, having sufficient clinical differences to justify our regarding them as distinct maladies. The second theory is thus enunciated by one of its foremost advocates (Steiner): "The attempt to distinguish croup and diphtheria as two entirely distinct diseases has been unsuccessful, both from an anatomical and a clinical standpoint; indeed there are many good reasons for supposing that these two affections are only varieties. and modifications of one and the same process, which, in consequence of special influences and collateral causes, as yet imperfectly understood, makes its appearance at one time as croup, at another as diphtheria, now in a sporadic form, now as a wide-spread epidemic, now as a primary, now again as a secondary affection."

The attempt to elucidate the nature of croup, and determine its relation to diphtheritic laryngitis, is attended by unusual difficulty for one who makes his observations in a locality where diphtheria prevails, as is the case with most of us who reside upon the Atlantic coast. The difficulty alluded to arises from the impossibility of making a clear and certain diagnosis of croup, where diphtheria is endemic. Has not every physician in such a locality, now and then, believed, that he was treating a case of croup, such as he had, perhaps, observed in former years, even adhering to the diagnosis till the death of the patient, when the subsequent history of contagiousness has taught him that, after all, the case was one of diphtheria? There is no symptom or anatomical fact observed at the

bedside which will enable the physician to say that the case is croup, and not laryngeal diphtheria. Absence of a pseudo-membrane upon the fauces does not, as some seem to think, establish the diagnosis of croup, for I have treated undoubted cases of diphtheritic laryngitis, ending fatally, in which there was not only no diphtheritic pellicle upon the surface of the pharynx, but only a mild degree of catarrhal pharyngitis. Nor is the absence of glandular swelling under the ears certain proof that the laryngitis is croupous, instead of diphtheritic, for, although it is true that considerable tumefaction is a sign of diphtheria, yet this swelling is sometimes absent in cases which are clearly diphtheritic.

For correct and reliable facts in regard to croup I have found it necessary to consult medical literature, and to depend upon my own recollection, and that of the older physicians of New York, as to cases which occurred prior to 1857, at which time diphtheria became established as an epidemic and endemic of the city, and upon the observations of intelligent physicians in localities where diphtheria does not prevail. I am under obligation to physicians who have thus aided me. The relation of croup to diphtheritic laryngitis may be conveniently considered under the following headings

I. Croup a local malady; diphtheritic laryngitis the expression or manifestation of a general disease.-The late Dr. Hillier, of London, a close observer of diseases, inclined to the belief that croup was a constitutional malady, but the following facts strongly indicate its local nature. Its causes, as we shall see, are the same or similar to those of the ordinary inflammations, which are admitted to be strictly local. There is no evidence, from the symptoms, of any systemic infection or blood disease, and recovery immediately follows relief of the local malady. The depression which attends cases of diphtheria is lacking. If croup were a general disease, there should be, it seems to me, in some cases at least, anæmia, poor appetite, weakness, etc., indicative of the blood change, for a longer or shorter time after the removal of the laryngeal obstruction and abatement of the inflammation.

As evidence, also, that croup is not a constitutional disease, is the fact that the inflammation is almost invariably-I have heard of no exceptional case-limited to a single tract of the mucous membrane. It is the uniform recollection of the older physicians of New York with whom I have conversed in reference to this matter, that they never observed a case of croup, before the advent of diphtheria, which was attended by membranous exudation upon other surfaces than that of the pharynx and air passages. Were there systemic infection, or blood poisoning, in croup, we should expect that, in some instances at least, the characteristic inflammation and exudation would occur in other localities also, as in diphtheria, especially since nearly every mucous membrane in the system is susceptible of croupous inflammation. Another fact indicative of the local nature of croup, is its tolerance of depressing remedies, as we shall see hereafter. Constitutional diseases having inflammatory lesions, badly tolerate such agents. From clinical and anatomical facts like the above, the profession has long regarded croup as a local malady, and I can see nothing in the most recent investigations regarding its nature to shake the belief in this opinion.

How is it with diphtheritic laryngitis, as this inflammation ordinarily occurs? Is it local, occurring independently of blood changes and produced by the lodgment of the diphtheritic virus upon the laryngeal sur

face; or is it the result of the presence of the diphtheritic virus in the blood, so that it sustains the same relation to the general disease, that the pharyngitis of scarlet fever and the bronchitis of measles do to those diseases? The latter theory, namely that the laryngitis and other inflammations of diphtheria are the result and outward manifestation of an infected or poisoned system, was generally accepted by the profession of this country and Europe during the last twenty-five years, until the publication of the bacterian theory. This theory (according to which it is claimed that a microscopic organism, which is the cause or specific principle of diphtheria, has been found making its way from the surface, on which it has lodged or been received from the air, through the tissues into the circulation) has shaken the belief of many in the constitutional nature of diphtheria, and they incline to the other view, which certain experiments seem to support, that diphtheria in ordinary cases begins locally, and that blood poisoning may or may not result, but that if it does, it is secondary.

It is a matter of great importance-an importance transcending that of almost any other subject relating to the pathology of this dreadful scourge that we should ascertain clearly and certainly which of the two prevailing theories is true, since the theory influences practice. Is the opinion correct, that the primary event is the entrance of the poison into the blood; or the other opinion, that the poison is received upon an exposed surface, where it excites inflammation, and that the blood either escapes contamination, or receives the poison by absorption or penetration from the inflamed surface?

Experiments on the lower animals have thus far failed to demonstrate the primary nature of diphtheria, as it occurs in the human race. Among the most recent experiments which have a bearing upon this subject, are those of Dr. Rajewsky, performed with the approval and at the instance of Prof. Von Recklinghausen. Rajewsky poisoned the blood of rabbits by injecting diphtheritic matter into it, and then produced catarrhal inflammation of the intestinal mucous membrane by injecting a weak solution of ammonia into the intestine, when the interesting result followed, that the catarrhal became a diphtheritic inflammation. Obviously in these experiments diphtheria was primarily constitutional. The diphtheritic inflammation was developed from within-from the poisoned state of the blood. But in another class of experiments, he first produced catarrhal inflammation of the intestines in the same manner as before, and then injected diphtheritic matter into the intestine. The result was the same as regards the production of diphtheritic inflammation upon the intestinal surface, for upon the inflamed portion, to which the poison was applied, the characteristic diphtheritic pellicle appeared. It may be inferred, that in this class of experiments the primary action was local, but may not absorption of the poison have preceded the local disease, as is now believed to be the case in syphilitic inoculations? (Bumstead.)

The fact that diphtheritic inflammations ordinarily occur upon those surfaces which are most exposed to currents of air, and upon which any deleterious substance floating in the air would be most likely to lodge, has been supposed to lend support to the theory that diphtheria is at first localized in these exposed parts. But if these inflammations were ordinarily produced by the direct contact of the poison received from the air,

I Lond. Med. Times and Gaz., Dec. 11, 1875.

coryza ought, it seems to me, to be the primary diphtheritic inflammation in a large proportion of cases; whereas it is not ordinarily primary, and in many cases does not occur at all. The fact is that the diphtheritic virus, in whatever way its reception occurs-whether in the ordinary manner, or through a wound of the skin-appears to be especially attracted to the fauces and contiguous parts, or to find in them the seat of its greatest activity, so that even if the disease is received through a distant part of the system, pharyngitis is apt to occur. Thus Hillier relates the case of an eminent surgeon who, performing tracheotomy on a child supposed to have croup, punctured his thumb. The puncture was painful, and on the following day a pustule occupied its site. This was opened and poulticed. "A day or two later, on removing the epidermis, the subjacent cutis was found in the condition of a peculiar dark slough; there was an entire absence of suppuration, and excessive pain. This was followed in six days by a diphtheritic deposit on the tonsils. The wound on the thumb was long in healing." A month later, diphtheritic paralysis occurred.' In cases like the above, if they are correctly interpreted, and the poison is received through the skin, it is evident that the inflammations on the exposed mucous surfaces are not produced by the direct deposit of the virus, but that they result from the blood poisoning. And the important and interesting fact appears, that, in cases thus contracted by inoculation, diphtheria is constitutional, before the pharyngeal or laryngeal inflammation occurs.

But if we could obtain no farther light in reference to the primary nature of diphtheria than what is afforded by experiments on animals and accidental inoculations in man, we would probably never know, when called at the commencement of a case contracted in the usual manner, whether we had to treat a merely local affection, or a constitutional disease with local manifestations. We must fall back to the wider field of clinical experience for help to an understanding of this matter. The following facts, taken collectively, afford, in my opinion, strong corroboration of the theory that there is primary systemic infection in diphtheria, as it is commonly contracted:

(1) The long incubative stage in certain cases.-Although the incubation of diphtheria is ordinarily from two to five days, it is sometimes an entire week, as in the following examples: In April, 1876, a little girl died of malignant diphtheria in West 41st Street, New York. Her sister, aged one year, remained with her from April 14 to 17, when she was removed to a distant part of the city, and placed in a family where there was no sickness, and had been no diphtheria. On the night of April 24, seven days after her removal, this infant was observed to be feverish, and on the following day, when I was called to examine her, the characteristic diphtheritic patch had begun to form over the left tonsil. In April, 1875, two sisters, aged seven and five years, resided with their parents, in a boarding-house, in West 22d Street, New York. A playmate in the same house had symptoms which were supposed to be due to a cold, but which were diphtheritic, when one night severe laryngitis occurred, and ended fatally the next day. The physician who had been summoned diagnosticated diphtheria, and the two sisters were immediately removed to a hotel. But seven days subsequently, diphtheria commenced in the older child. The younger was at once removed to a distant part of the same hotel, but on the sixth or

Hillier on Diseases of Children.

seventh day subsequent she also became affected with a fatal form of the disease.

Now according to the doctrine that diphtheria is at first local, and that the inflammations result from the irritating effect of the virus. which lodges upon the mucous membrane, this virus must remain inactive a week upon the surface where it is received. Such inactivity in a poison of unusual energy and malignity would be very improbable. But we have sufficient explanation of the long incubation, if, in whatever way the poison is received, it first enters the blood, and the inflammations occur consecutively to the blood-changes. It is a law in pathology that those specific diseases which have an incubation of several days, are constitutional.

(2) Another fact, which indicates primary blood poisoning in diphtheria, is observed in certain cases, namely, the occurrence of severe constitutional symptoms for a longer or shorter time, perhaps for half a day, before the appearance of the usual inflammation. Thus a girl of five years, having malignant diphtheria, whom I saw in consultation, was carefully examined on the first day of her sickness by the attending physician, and although he closely inspected the fauces, there was no appearance which indicated the nature of the malady till the subsequent day. In such cases, a sufficient number of which I have observed, there is apt to be complaint of soreness of the throat, or difficulty in swallowing, almost from the beginning of the general symptoms; but the pain and tenderness seem to be in the deeper tissues of the neck, and the fact that redness of the mucous surface does not appear till some hours subsequently, is evidence that the inflammation is developed from within, and not from the irritating effect of the poison upon the surface.

Again, treatment of the inflammations by the most reliable and efficient antiseptics and disinfectants which we possess, commenced at the earliest possible moment and repeated at short intervals, does not prevent the occurrence of indubitable symptoms of blood poisoning in cases of a severe type. Thus I have treated every portion of the inflamed surface, as far as it was accessible, every second or third hour, with carbolic acid and other disinfectants, almost from the very commencement of diphtheria, and so thoroughly that any vegetable or animal poison, with which the remedies had come in contact, would probably have been destroyed, or rendered inert, and yet, except in mild cases, symptoms of diphtheritic blood poisoning have occurred, and as early and uniformly as if less energetic local measures had been employed. While, therefore, I do not fail to recommend local treatment as calculated to prevent septic poisoning, and relieve the inflammations, I have lost confidence in it as a means of preventing the entrance of the diphtheritic poison into the blood. Its powerlessness to prevent contamination of the blood by the diphtheritic virus is an additional evidence that this contamination occurs independently of the local disease, and probably precedes it.

(3) The quick succumbing of the system in certain malignant cases is evidently due to diphtheritic toxæmia. We sometimes observe a fatal result on the second, third, or fourth day, without any dyspnoea, or sufficient laryngitis to compromise life. Cases of this kind, terminating fatally even in the first day, have been reported. The system is suddenly overpowered by the poison, struck down, as it were, by the profound blood change, while the inflammations are still in their incipiency.

(4) Important evidence of the constitutional nature of diphtheria is afforded also by the state of the kidneys. No internal organs are so often