HARVARD HEALTH TALKS THE CARE OF CHILDREN BY JOHN LOVETT MORSE PRESERVATIVES AND OTHER CHEMICALS IN FOODS: THEIR USE AND ABUSE BY OTTO FOLIN THE CARE OF THE SKIN BY CHARLES JAMES WHITE THE CARE OF THE SICK ROOM BY ELBRIDGE GERRY CUTLER THE CARE OF THE TEETH BY CHARLES ALBERT BRACKETT ADENOIDS AND TONSILS BY ALGERNON COOLIDGE AN ADEQUATE DIET BY PERCY GOLDTHWAIT STILES HOW TO AVOID INFECTION BY CHARLES VALUE CHAPIN PNEUMONIA BY FREDERICK TAYLOR LORD HARVARD HEALTH TALKS HARVARD HEALTH TALKS PNEUMONIA BY FREDERICK TAYLOR LORD, A.B., M.D. VISITING PHYSICIAN, MASSACHUSETTS GENERAL HOSPITAL CAMBRIDGE HARVARD UNIVERSITY PRESS 1922 COPYBIGHT, 1922 HARVARD UNIVERSITY PRESS HARVARD HEALTH TALKS PRESENTING the substance of some -* of the public lectures delivered at the Medical School of Harvard Univer- sity, this series aims to provide in easily accessible form modern and authorita- tive information on medical subjects of general importance. The following committee, composed of members of the Faculty of Medicine, has editorial supervision of the volumes published : EDWARD HICKLING BRADFORD, A.M., M.D., Dean of the Faculty of Medicine, and Professor of Orthopedic Surgery, Emeritus. HAROLD CLARENCE ERNST, A.M., M.D., Professor of Bacteriology. WALTER BRADFORD CANNON, A.M., M.D., George Higginson Professor of Physiology. PNEUMONIA PNEUMONIA REFERRING to pneumonia, Osier writes: "One of the most wide- spread and fatal of all acute diseases, pneumonia has become the 'Captain of the men of Death' to use the phrase applied by John Bunyan to consump- tion." FREQUENCY AND IMPORTANCE In this country about 10 per cent of all deaths are each year due to some form of pneumonia and this annual toll of lives has been maintained with little apparent variation for many years. Strictly com- parable statistics are lacking for other communities but, making due allowance for differences in classification, a similar high prevalence seems to obtain also in other civilized countries in which mor- tality statistics are available. HARVARD HEALTH TALKS While the disease is constantly a menace and thus termed endemic, nu- merous instances might be cited of more or less severe local outbreaks or epi- demics at certain times and in certain places as a succession of cases in the same house, on shipboard, in hospitals and in jails. Conditions of overcrowding are largely responsible for such epi- demics. In 1906 the death rate among negroes employed in the construction of the Panama Canal reached eighteen per thousand. A similar high mortality has been noted among negroes employed in the mines on the Rand and in 1912 the death rate from pneumonia was twenty- six per thousand. In Panama and on the Rand the highest mortality occurred among the recent arrivals and the mor- tality rapidly diminished after a short residence in the community. We have unfortunately just passed through a period of greatly increased prevalence of pneumonia during and 10 PNEUMONIA after the influenza pandemic. In the absence of any reliable figures it is futile to speculate as to the number of deaths from pneumonia in the country at large during the scourge of influenza, but the importance of pneumonia as a cause of death is strikingly illustrated in the re- port of Vaughan and Palmer for the United States Army during the World War. Of about 4,000,000 men, about 40,000 perished in combat and 47,000 died from disease. Pneumonia accounted for more than 50 per cent of the deaths from disease prior to the influenza pan- demic in 1918 and for 93.7 per cent dur- ing the period covered by the pandemic. Men from the rural districts and the southern communities suffered most severely. Excluding the influenza period from consideration, pneumonia was nine times more frequent among the men in the army than among civilians of the same age group. The high incidence of pneumonia in the army may be 11 HARVARD HEALTH TALKS ascribed to epidemics of measles and influenza followed by pneumonia, an increased opportunity for contagion in the close proximity of susceptible indi- viduals in barracks, tents, and the mess, and a lowering of resistance from ex- posure, overwork, and fatigue. TYPES OF PNEUMONIA I have thus far spoken of pneumonia without distinction as to type and be- fore proceeding further it will be neces- sary to define the two recognized forms of the disease; one is spoken of as lobar pneumonia from the more or less complete involvement of one or more lobes of the lung in an inflammatory process. In this type there is practically always one group of bacteria, called pneumococci, to be found in the lung and frequently also in the blood. Lobar pneumonia is a disease with a well-de- fined and uniform onset, usually with initial chill, rapid elevation of tempera- 12 PNEUMONIA ture, pain in the side, cough and bloody expectoration, running a febrile course of about seven days and terminating abruptly in favorable cases. The second type is known as bronchopneumonia and here the bronchi or smaller air pas- sages and even their smallest ramifica- tions in the lungs together with the ad- jacent or terminal air vesicles and the neighboring lung are the site of an in- flammation. In bronchopneumonia the infecting agents are usually micro-or- ganisms normally inhabiting the mouth, and hence the bacterial flora of the mouths of normal persons to a consider- able degree determines the bacteriology of the disease. The pneumococcus is the most common single cause but other or- ganisms are also concerned and mixed infections with more than one kind of bacteria are not uncommon. In con- trast to the usual, well-defined and uni- form onset and abrupt termination of the symptoms in lobar pneumonia, bron- 13 HARVARD HEALTH TALKS chopneumonia presents a variable pic- ture, occurring as a complication of con- ditions likely to mask or modify its manifestations and with a variable ex- tent of lung involvement. CAUSES In considering the causes of pneumonia, it is desirable to distinguish between the predisposing and immediate causes. Among the predisposing causes suscepti- bility is increased as age advances. It is greater among males than females, prob- ably on account of the greater oppor- tunity for infection in occupations among males. The subjects of chronic alcoholism are somewhat more prone to have pneumonia as suggested by an apparent higher percentage of heavy drinkers in patients admitted to hospi- tals with pneumonia than in the other patients and in the population at large. There is a marked seasonal variation in the incidence of pneumonia, a large 14 PNEUMONIA majority of the cases occurring during the months between November and June. The explanation is uncertain but the tendency to live under less satisfac- tory hygienic conditions in crowded and poorly ventilated rooms during cold and inclement weather may be responsible. A greater incidence of pneumonia in the city than in the country suggests that overcrowding is a factor of importance. Close contact within doors increases the opportunity for transmission of infected material from one person to another through the distribution of particles by loud talking, coughing, and sneezing in houses, theatres, halls, barracks, street cars, etc., and contamination by fingers soiled with saliva or sputum. ^ The increased susceptibility of recent arrivals in a community, as in the United States Army, in Panama, and on the Rand, may be ascribed to less previous exposure and consequently less acquired resistance to organisms which abound in 15 HARVARD HEALTH TALKS crowded communities. Such debilitating conditions as hunger, fatigue, exposure to wet and cold, the later stages of car- diac disease with passive congestion of the lung, malignant disease, chronic nephritis, cerebral hemorrhage and other diseases are also to be regarded as pre- disposing factors. A history of acute infection such as accompanies an ordinary "cold" can be obtained in from 25 to 50 per cent of all cases of lobar pneumonia and such in- fections may be regarded as important predisposing factors, the specific agent of the "cold" (as yet unknown) prob- ably acting to carry down the cause of pneumonia into the deeper parts of the respiratory tract and leading to its im- plantation in the lung. Measles, influ- enza, and whooping cough are also not infrequently followed by pneumonia, more often of the bronchopneumonic type. In these three diseases the specific cause, likewise unknown, probably acts 16 PNEUMONIA in similar fashion to implant the pneu- mococcus within the deeper parts of the tract. Bacterial cause of pneumonia. The pneumococcus is practically the only immediate cause of lobar pneumonia and the most common single cause of bron- chopneumonia. Our knowledge of the organism extends over a period of thirty years and goes back to its independent and almost simultaneous discovery by Sternberg in September and by Pasteur in December, 1880. Unfortunately for American medicine, Sternberg's article did not appear until April, while Pas- teur's publication is dated January, 1881, and the priority of the discovery there- fore belongs to Pasteur. The importance of the pneumococcus, however, was not appreciated until its frequent presence in pneumonia was established by Fraenkel in 1884 and later by Weichselbaum in 1886. It is a lance-shaped organism occurring in pairs or chains. 17 HARVARD HEALTH TALKS The pneumococcus has interesting biologic peculiarities which are doubtless concerned in its behavior as an infecting agent. It is very sensitive to change in the reaction of the media in which it grows and growth can be started in arti- ficial media only at a reaction very close to that of the circulating blood which is slightly alkaline. In artificial media con- taining carbohydrate such as glucose, however, growth, once started at a slightly alkaline reaction, proceeds until the media become slightly acid, further multiplication being inhibited by the acid produced. Its extreme sensitiveness to acid may be better appreciated when it is stated that the range between the slightly alkaline reaction of normal blood and that of the culture containing glucose in which death of the organism takes place is about that between ordi- nary tap water and distilled water stand- ing in the laboratory. The lower animals vary in their sus- 18 PNEUMONIA ceptibility to infection with the pneu- mococcus, chickens and pigeons being immune, and rabbits, rats, and mice highly susceptible. The readiness with which artificial infection of these lower animals can be produced in the labora- tory has led to an important addition to our knowledge of the organism and an advance in treatment of one type of the disease with consequent reduction of mortality. The pneumococcus is found in the saliva of more than one half of all normal persons. It is only within the past ten years, however, that we have known that all types of pneumococci are not of equal importance and it will be a reassur- ance for me to state at once that the kind most frequently the cause of the more severe types of pneumonia is not commonly present in the normal mouth. 19 HARVARD HEALTH TALKS TYPES OF PNEUMOCOCCI Previous to the work of Neufeld (Arb. a. d. Kais. Gesund. 1910, xxxiv, 293) in Germany and of Dochez and Gillespie (Journal Am. Med. Ass., Sept. 6, 1913, Ixi, 727), in this country, it was thought that there was no essential difference in the strains of pneumococci. By the re- peated inoculation of horses with differ- ent strains it has been found, however, that after a time the animal's resistance against the organisms injected is such that when its blood is taken and allowed to separate into serum and clot, the serum will protect white mice against an otherwise fatal dose of certain strains of pneumococci. The serum is not only pro- tective but will also cure an otherwise fatal infection. It is further found that these strains against which the horse serum is effective can be recognized by a clumping or agglutination of the pneu- mococci when mixed in suspension with 20 PNEUMONIA the horse serum. By such protective and clumping experiments three so-called "fixed" types of organisms have been separated out of the great group of pneu- mococci. In the first column (A) of the table (page 23) the groups are indicated by the Roman numerals. The types numbered I, II, and III are the fixed types. Type IV is made up of pneumo- cocci with apparent individual characters and resistance against one strain of this type confers no protection against other strains. It is thus spoken of as a hetero- geneous group. As shown in the second column (B) Types I and II are only rarely present in the normal mouth, while Types III and IV are common. Among persons intimately associated with pa- tients with lobar pneumonia, however, such as attendants, relatives or friends, the percentage of those who harbor Type I or II pneumococci may rise as high as 13.0 per cent. (A very, Chickering, Cole, and Dochez. Monographs of the Rocke- HARVARD HEALTH TALKS feller Institute for Medical Research, No. 7, October 16, 1917, p. 95.) Relation of types of pneumococci to types of pneumonia. I cannot give you statistics on the incidence of the different types in bronchopneumonia but their approximate frequency is indicated by the plus signs in the column (C). As in the saliva of normal persons Type IV is most common, Type III is probably next in frequency and Types II and I are rarely present. I would like to point out also that the similar grouping in the saliva of normal persons and in broncho- pneumonia is what we should expect as the infection here is usually due to bac- teria commonly inhabiting the mouth and carried down into the deeper parts of the respiratory tract. The approximate distribution of types in lobar pneumonia, determined by Cole and his associates, is shown in the fourth column (D). Out of every 100 cases about thirty are due to infection with 22 g^g I Illl 1 p* S.2^*o fe * * J " 1 o 1 W 1 1*1-8 1 I W illM 5 I s g s s s L ilSlI o o ** 00 |s " - a ^ 3 0.^.2 > o 1 sN a c 1 S .l.S*o 1 . I 1 -" s Q !8i s ^ 5 % it gj.2 + + + + + sj fi u ill O i^ m I - S ^.2 o. + * I Dochez, for Medi iicine. 3|Jj K 8*3- III 00 o * . m 50 0* CO CO