Part 4

It is imperative to note the accurate clinical observations recorded from the numerous epidemics of the past by men with far less data to go upon than is available at the present day. The high morbidity among the personnel of many of our hospitals and institutions where the infection occurred and the relatively low mortality deserve attention. This may be partly explained by the methods of treatment of those infected, but not entirely. The great likelihood of carriers of influenza, who either are not ill or who are suffering from very mild infection, is an observation also noted by former writers which cannot be ignored. The value of the masks has not been established, although they have been extensively used in many parts of the country. Frequent throat lavage was generally accepted as a rational preventive measure. Relightings of the disease have been noted in most of our cities after the subsidence of the epidemic. Vaccination against influenza is fully discussed in Dr. Haythorn’s paper in this series.

The presence of influenza in San Quentin prison, California, in April, 1918 (Public Health Reports, May 9, 1919); an epidemic of respiratory disease in Chicago in the spring of 1918; the report of Soper of influenza in our army camps in March and April, 1918; the occurrence of influenza in Porto Rico in June; influenza on a United States Army transport from San Francisco, as reported by Coutant, seem to point to the possibility that influenza had a footing in America long before the disease became pandemic. The view held by some that the beginning of influenza was in America, subsequently being transferred to Europe and then reimported here, is worthy of consideration. Coutant believed the disease originated in Manila, others that it traveled from “a permanent endemic focus in Turkestan,” and there are many other theories which attempt to discover the original source of the disease. The question is today an unsettled one. The pandemic of influenza in its severest form swept so suddenly over the world that before the profession realized it or had become stabilized it had changed its character and the great plague was gone. The consequence has been that we have really learned little that is new and have done scarcely more than establish on a firm basis many of the opinions formed after the great outbreak of some 30 years ago. Because transportation is today more rapid than it was at that time, so the spread of the disease has been correspondingly swift. Our modern life, the congregating crowds in theatres, moving-picture houses and in lecture halls, as well as of the men in our training camps, the development of street cars and the more frequent traveling by train—these and many more changes in our mode of living have served to aggravate the conditions favoring the widespread distribution of the infecting agent. A higher proportion of the population was, therefore, attacked than in any previous pandemic, and the period during which the disease was widely prevalent has for the same reason been relatively much shorter.

The characters differed somewhat in different regions, but the evidence shows clearly that we are not dealing with any new disease. It will be years before we are able to fully analyze the data that have been collected from such wide sources and by so large a body of trained men, so that important epidemiological facts may still be forthcoming from the material already at hand. We are too close to the events to get the most helpful perspective, and the object of this report has been to add, in however small a degree, to the general knowledge of this great pandemic as it has appeared to us in Pittsburgh and its surroundings.

A CLINICAL DESCRIPTION OF INFLUENZA AS IT APPEARED IN THE EPIDEMIC OF 1918–1919

By J. A. LICHTY, M. D.

The epidemics of influenza which have been recorded from time to time during the past few centuries have always contributed an interesting chapter to the history of medicine. The protean character of the disease with its many complications is always an excuse for another attempt at the description of the clinical manifestations of a recent epidemic. This is not, however, the only incentive at the present time for describing the clinical aspect of the disease as it appeared in the epidemic through which we have just passed. The study of the disease from other aspects, such as the pathological, the bacteriological and the physiological, by well-organized groups of workers has made it necessary to co-ordinate, if possible, the clinical findings in every detail with these apparently basic principles. It would be interesting to review here the peculiarly fortunate circumstances which have led to the investigations. On account of the great war many temporary laboratory organizations which otherwise would not have existed were in operation, and these organizations, moreover, were keen to undertake any laboratory problem which might arise. The present epidemic presented the opportunity, and that the work was taken up with great enthusiasm is evidenced by the reports coming from the various army hospitals, base hospitals and civilian hospitals throughout the world. The permanent laboratories connected with medical schools and with institutions for medical research took up the problems with equal endeavor. This brief reference is made only to call attention to the fact that from such organizations a great mass of information has come which must be critically reviewed and coordinated before it can add to the permanent fund of our knowledge of the disease under consideration.

The material upon which the following clinical observations have been made is peculiarly adapted to review because it consists of two distinct groups of patients which were admitted to the Mercy Hospital. One group of 153 men was composed of soldiers between the ages of 18 and 23, which had been recently inducted into the Student Army Training Corps, and were living in barracks in the immediate vicinity of the hospital. Another group consisted of civilians (394), ranging from youth to old age, which came from various parts of the city and surrounding towns and country. The first group came to the hospital early, or as soon as the disease was recognized; the second group came usually after several days of illness had elapsed, or when a complication had already arisen. Many of this group had been ambulatory cases for the first part of the disease. The entire number of patients admitted to the Mercy Hospital from the first admission, September 21 to December 1, the end of the quarantine, was 547. After December 1 very few simple influenza cases were admitted. These 547 cases form the basis of the observations which will be referred to in this paper.

From the last great epidemic or pandemic of influenza, that of 1889 and 1890, have come clinical descriptions which should be reviewed before speaking of the clinical manifestations which have characterized the present epidemic as shown in the two groups studied.

One of the best descriptions of that epidemic was given by Dr. O. Leichtenstern in Nothnagel’s Encyclopedia of Practical Medicine. This contribution, among many others, describing the epidemic of 1889 and 1890 is one of the first to refer to the Pfeiffer bacillus as being etiologically associated with the disease. It differs, therefore, greatly from descriptions of previous epidemics. Leichtenstern says: “The typical influenza consists of a sudden pyrexia of from one to several days duration, commencing with a rigor, and accompanied by severe headache, generally frontal, with the pains in the back and limbs, by prostration quite out of proportion to other symptoms and marked loss of appetite.” He continues by saying that to these characteristic symptoms may be added the catarrhal phenomena arising from the affection of the respiratory tract, particularly the upper (coryza) and “occasionally” the lower, the trachea and bronchi. This description is so in accord with the symptoms of uncomplicated influenza as found in the present epidemic that very little need be added. Any difference which may occur in the description of the disease is likely to be accounted for by the peculiarity of onset, whether in the upper or lower respiratory tract, and by the different ways of interpreting complications which may have arisen. It is evident from this description that the upper respiratory tract was affected more generally than the lower in the epidemic of 1889 and 1890. In the present epidemic it can safely be said that the reverse was the usual state of affairs. It was a rather unusual occurrence when the affection was limited only to the nose, pharynx, larynx, trachea and larger bronchi. A very large number, no doubt, had a peculiar œdema, a so-called “wet lung,” which we shall discuss later; others went on to a capillary bronchitis or a bronchiolitis, and a large number had broncho-pneumonia. This sequence we shall attempt to show in the statistics at hand. In some cases the lesion in the lower respiratory tract seemed to be primary, there having been no initial coryza. At least none was observed and no history was obtained.

Prodromal Stage and Communicability

The length of the prodromal stage—the stage from the time of contact to the earliest onset of symptoms—has always led to interesting observations and discussion. In this epidemic we have rather definite information bearing upon this subject.

A young married farmer living in a rural community where no influenza had occurred up to the time of the present experience went to a city about 40 miles distant. On the train he sat in the same seat with a man who was apparently ill, and who was sneezing and coughing. He was in the city only a few hours, and was not in any place of congregation except the railway train. Forty-eight hours after his return to his home he noticed the first symptoms and began a mild course of influenza. About 50 hours later his wife was taken with the same symptoms, and in two days more their only child was afflicted. Other members of the household were also afflicted, and one of them died of pneumonia.

It might be interesting to quote a similar observation made by Macdonald and Lyth, of York, England, published in a recent issue of the British Medical Journal (November 2, 1918, p. 488), which corroborates this experience. They say: “We traveled from London together on Thursday, October 3, by train, leaving King’s Cross at 5.30 P. M., arriving in York at 9.30, and as we were leaving the carriage a young flying officer, who had come the whole way with us and was coughing and sneezing at intervals, informed us that he was ill and had had influenza for several days. On Saturday, October 5, we both became ill and had developed typical attacks of influenza. With both of us the illness developed suddenly with laryngitis; in both the first signs were a severe attack of coughing; and in both the time was noted fairly accurately as being between 2 and 2.30 P. M. One case was quite mild, the temperature never over 101. The other was more severe; the temperature arose to 104½ and the catarrh extended to the bronchi. His wife and two children also developed influenza, and in their case the symptoms showed suddenly, about 2 P. M., on Monday, October 7. Now we are convinced that we became infected from our traveling companion during the train journey—more likely toward the end of the journey; and if we take the time of infection as 9.30, this fixes the incubation period for both of us at a minimum of 41 hours, with a maximum margin of error of 4 hours. The three cases developing in the family of one of us point to a similar incubation period, as their illness started almost exactly 48 hours after his, and as it is likely that the infection would not take place until a few hours after the first symptom, the incubation period in these three cases must have been nearly the same as our own two.

“It can be readily understood that we were in no position to conduct extensive bacteriological examinations, but a culture taken from the posterior nares of one of us on October 10 with a guarded swab showed colonies of Pfeiffer’s bacillus and of micrococcus catarrhalis.”

This observation is so convincing, I have quoted it at length and in full.

The communicability of influenza has been observed by all, and the ease with which it passes from one individual to another noted. One observation made by us was of considerable interest. In a house where a patient lay sick with a severe attack of influenza for nearly three weeks several members of the household passed the door of the sick room a number of times daily, and yet they did not contract the disease. This is in marked contrast with the immediate contact between the two physicians and the young flying officer, who sat in the same railway carriage compartment for four hours. The same observation was made in the hospital among nurses in direct contact with patients. A large number of these contracted the disease, while those not immediately associated with influenza patients almost invariably escaped. This speaks strongly against the idea that the epidemic was a so-called “plague,” or that it passed without intermediate means through the air and pervaded all places.

From information thus far at hand it seems, therefore, that the prodromal stage, or stage of incubation, is one which covers about 48 hours, and that it is usually without symptoms unless it be a peculiar prostration which had been described by some patients. It would also appear from the experiences just narrated that it was necessary to be in rather close contact with a patient, so that there could be an exchange of respired air before infection could take place.

Duration of the Disease

In all descriptions of the disease the duration is spoken of as “several days, more or less,” “a three-day fever,” or “a seven-day fever.” Because of the careful supervision under which the soldiers were kept while in the barracks an excellent opportunity was afforded to note the duration of uncomplicated cases. The shortest time observed was 1 day, and the longest 10 days. The average duration of temperature among 87 soldiers without inflammation of the lungs or other certain complications was 6⅓ days. Among the civilians the shortest time of pyrexia was a few hours only, while the longest in 73 male patients was 14 days, and in 84 female patients was 16 days. The average length of pyrexia in the males was 4⅝ days, and in the females was 5¼ days.

While the very definite clinical description of the former epidemics of a so-called uncomplicated influenza seems to have served satisfactorily to the present time, the laboratory studies and the possibly more thorough clinical observations which have been carried out recently in this epidemic make it necessary to present anew the whole disease picture of influenza, with the hope of suggesting a classification more in accord with our present knowledge of the disease.

Forms and Varieties of Influenza

A few words as to “forms” or varieties of influenza might be helpful before suggesting a classification of symptoms. In former epidemics of influenza considerable importance was attached to the early manifestations or first symptoms as characterizing the “form” of influenza which was in evidence in the individual patient. These were reported as a “respiratory form,” a “nervous form,” a “gastro-intestinal form,” and other forms—circulatory, renal, psychic, etc. In the epidemic of 1889 and 1890 particularly these types were noted, and they have been described in the subsequent small epidemics, practically characterizing them as being of one or the other, and frequently as being without any respiratory symptoms. In the study of our group of cases in the present epidemic every effort was made to recognize the non-respiratory cases, but we were unable to find a single case which did not have definite respiratory symptoms, either early or late, in addition to any other symptoms present. Only occasionally were nausea, vomiting and diarrhea or tachycardia, or certain neuroses or psychoses, the leading symptoms. The respiratory symptoms in some cases seemed to be at the onset primarily of the lower respiratory system—that is, without the preliminary coryza. These usually ran a rapidly fatal course, characterized by marked cyanosis and confusingly irregular chest signs. We would say, therefore, in so far as our experience goes in this epidemic, we are not justified in speaking of any particular forms except the respiratory form, and whenever pronounced manifestations occurred justifying a characterization of any other form they could more easily be interpreted as a complication, or the manifestation of a coincident disease, or of a severe toxæmia.

The classification of the symptoms, therefore, takes into consideration largely those symptoms arising from the respiratory system. We are of the impression that the pathology demonstrated by Dr. Klotz and described by others justifies the following classification. Clinically we would recognize two distinct groups of epidemic cases.

The first includes those without lung involvement having symptoms arising from the upper respiratory tract, including the trachea and the larger bronchi. These were practically without any chest signs except for the rather indefinite signs of an acute bronchitis, and the only symptoms referable to the respiratory tract were a coryza, soreness of the throat, hoarseness and a cough of varying degree and character. If to these symptoms are added those of Leichtenstern just mentioned, one will have a good description of a so-called simple, uncomplicated influenza.

The second includes those with lung involvement and associated with physical chest signs, in some indefinite and confusing, while in others definitely conforming with the existing pathology. These symptoms and chest signs were those associated at one time with what appeared to be an acute œdema of the lungs. At another time the physical signs were those of a bronchiolitis (capillary bronchitis), or most frequently of a broncho-pneumonia, of an isolated type or of a massive type. Finally there were some forms of lobar pneumonia which at times we were unable to differentiate from a true lobar (croupous) pneumococcic pneumonia.

Influenza Without Lung Involvement

Of the group without lung involvement nothing further would seem necessary to be said in addition to what one finds in standard text-books describing the disease picture of former epidemics. The incidence of influenza of this type among our group was as follows: Of 153 soldiers 93, or about 60 per cent., had a so-called simple, uncomplicated influenza, and of the 394 civilians 185, or about 52 per cent., had no lung involvement. There are a few points in which the symptoms of the present epidemic seem to be so peculiar that they merit special consideration.

The Temperature