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FILE NAME: Metropolitan Life (ML) DATE: 1940 Nov DOC#: ML046 DOCUMENT DESCRIPTION: Journal Article - Pneumoconiosis, by Dr. Lanza Southern Minnesota Medical Association, Norths i ijActtdetny of Medicine and tMinneapolis Surgical Soda |s;a- ^ i , : MiiiNESoi^ Sj a -ix M edical Association 1,1940 40 c e n ts a 1.00 a y ear sal t',., , ^ ` -^ ^ iftta h jin a se in flieP'Treatment oi Urticaria of M*.t i r Pr^ncy.-j|f *# '/. S. BlumetithM, M.D, Minneapolis, Minnesota 797 Ki- & ,, H istory of Mebicinf in Minnesota : l i t , "Uisiiases of t l^ Dakota Indians. (Continued frans'' October issue) . Thomas S. Williamson, M.B.\............................ 798 Jfr/CdiuiNary DisbasJ' t " ft# Paul,Minnesota...... 77S Dakota Medicine. Rev. Thomas S. Williamson.................................. 801 P resident's Letter .................................. ,.................... 806 fp& & , New York, N. Y........... 776 Cys? ob the T horax Simulat- Bip|p&#A, , ` _ ISiMSi and RobertWoodruffs H p*.M-i' '|f|fw^s..n.t.a..,.......... ............a4 781 JS Til OfcCt-RRF.NqH AND PREVBNT&N Ssqsrt Mbstesata... 783 Who Is ^ j Jtoqhestpr, Mittiewtft.Jife E ditorial : Historical Highlights on Appendicitis................... 8.07 A Safe Safety Pin .............................. ................... 808 M edical. E c o n o m ic s : The Blind Goddess.............................. 809 Minnesota First ............................................. 809 National Health Program--1940............................... 81(1 Medical Inducti6n Boards ........................................ 812 Privileged Communications .................................... 812 Thanks of the Council ............................................ 813 Minnesota Stifte Boarid of Medical Examiners... 813 *, . A.C,om' m. u\nica. t.ion; ...t.\.>..'............................................... 814' S i f; <, *' ..Of General Interest ......................................... 815 M fe StlbiQRMM *;,/f * if r ^ v SJAN'S A U X J p ,R Y - t 1 31940 821 IS; f 7' - a t'il* ........ .. & of postage provided for in '* <* s*f* 4 .k PNEUMOCONIOSIS---LANZA . ; interpretation may be of the utmost value, the it is of almost no value in the diagnosis of valvu* interpreter must have a summary of the clinical lar defects. history and physical findings. 3. The electrocardiograph may eliminate thfc Summary heart as a source of symptoms suggestive of myo*s 1. The electrocardiograph definitely aids in cardial disturbance. ' the diagnosis and management of coronary dis 4. The interpretation of the electrocardiogram ease and serial electrocardiograms are invaluable. must be made by a thoroughly trained individual 2. The electrocardiograph is only informative and the findings must be correlated with the clint-, on the anatomical condition of the heart and in cal history and physical findings. no vyay aids one in determining the functional 5. The electrocardiograph, of and by itsell capacity of the heart or its ability to do work and cannot make the diagnosis and prognosis for yoti PNEUMOCONIOSIS* A. I. LANZA, MJ5. Assistant Medical Director Metropolitan Lifo Lnsuranca Company New York, N. Y. I^EUMOCONIOSIS is a generic term whose use at times has been attended with some confusion. It embraces the reactions of pulmonary tissue to industrial dusts, which in some instances' present ,clear-cut diseased conditions ; in others, condhDns which are not entirely clear; and in still others, conditions which have little or no clin ical significance. Much water has gone over the darn since attention was first called to the impor tance of dust exposure in industry as a cause of pulmonary disease. A little over thirty years ago, when the campaign against tuberculosis was well under way, the statisticians began to call atten tion to the fact that workmen in dusty trades had a consistently high death rate from tuberculosis. It was surmised that many kinds of dust, by vir tue of their physical properties of hardness, sharpness, and insolubility, produced a mechani cal injury of the lungs which paved the way for a tubercle infection. With respect to certain or ganic dusts which did not have physical proper ties calculated to injure the pulmonary tissue, it was felt that these probably acted as conveyors of the tubercle bacillus. This seemed a reason able explanation for the excess mortality from tuberculosis observed among certain groups of textile workers, tobacco workers and leather workers. .. Disability and a high mortality were so con spicuous in what was commonly termed the hard rock mining industry that it was but natural that *Address at the annual meeting of the M innesota State M edi cal A ssociation, R ochester, M innesota, A pril 23, 1910. 776 anti-tuberculosis workers should stimulate inves tigation of that type of underground work andf first clinical study of pulmonary dust disease WI4, made about twenty-five years ago by the Unite*}-* States Public Health Service and the Bureau oP Mines, to be quickly followed by others in vji|| rious parts of the country. These early investiga tions were mostly confined to the mining induS*. try, except for the studies made in the textile* industry by a group of physicians in Philadelphia^ Investigations were made in industrial munities over long periods of time. This pf cedure offered the tremendous advantage of servation of industrial workers ranging f those new in the industry to those who had employed for many years, and thus made ble a correlation between the symptoms presented and the length of employment and working conditions in various occupations to*, same industry. There was gradually built comprehensive knowledge of the etiology of monary dust disease which led to a clearefderstanding and did away with many false conceptions. The most conspicuous fact was where workmen were exposed to dust cpni ' free silica in large amounts, they contract definite and specific type of pulmonary that this fibrosis produced characteristic ances on an x-ray film, and was accompa a consistent progressive clinical picture, dyspnea on exertion was the outstanding Sf. tom. It was learned in time that the symptoai4` M innesota PNEUMOCONIOSIS -LANCA valvu- sented by any group of workmen bore a definite no part in causing pulmonary fibrosis has held relationship to the severity of such silica ex good. posure. In other words, the symptoms and prog Attention was naturally directed to other in ress of the disease were directly proportionate dustries which involved exposure to dust con to the amount of silica which invaded the pul taining silica in many forms---that is to say. com monary tissue. It was conspicuously apparent bined silica- as well as exposure to other types that in communities where men were exposed to of noil-siliceous inorganic dust. Here investiga a severe silica hazard, the incidence of and mor tors found that the picture of'disability and dis tality from tuberculosis was extremely high, in ease seen among those exposed to free silica was ! iThn*-?v^ itself, some instances so high as to be hardly credible. conspicuously absent. Various terms such as r vou. This tuberculosis mortality, however, was in chalicosis and siderosis fell into the discard and He TT sharp contrast with that of surrounding commu other designations, such as potters' rot, grinders' T#i nities and even with that of the workers' families. rot, miners' phthisis, and miners' consumption There was built up a concept of an occupa were found to relate to identical conddions and tional disease resulting from the inhalation of were supplanted by the term silicosis. free silica dust, manifested primarily as a fibrosis Pield studies of various industries went hand evenly distributed throughout both lungs, which, in hand with animal experimentation in which dependent upon the circumstances of exposure to were employed dusts similar to those found in silica dust, would progress with the gradual de industrv. Animals were exposed to the inhala mves- velopment of disability. Secondarily, especially tion of these dusts in specially prepared dusting tindthe where the silica damage to the lungs was of a chambers and (iardner, at tlie Saranac Labora se was United eau of in vaestigaindust extile leiphia. ,1 cern considerable extent, tuberculous infection was apt to appear. Infection wuth the tubercle ba cillus was more than merely a terminal episode and these two conditions reacted upon each oth er, definitely increased disability, and frequently led to a fatal termination. When death occurred as a result of pulmonary involvement in the great majority of cases, infection with the tubercle bacillus was present. tory, was the first to demonstrate silicosis in ex perimental animals. The method of intraperitoneal injection, with the technique of Miller and Sayers, was also used. The underlying motive for all this was to determine which industrial dusts were harmful, that is, would cause a pneu moconiosis of such a type or degree as to pro duce disability. Among the dusts investigated both m industry iis pro There came to my attention within the past and in the experimental laboratory were lime of ob- month the report of the Miners' Phthisis Pre stone, calcium carbonate, gypsum, cement, feld g from ad been vention Committee of Johannesburg, South Afri spar, soapstone, talc, precipitator ash, artificial ca, for the three-year period 1935-1938. The abrasives, seriate and others. None of these, e possiis they authors summed up the experience of thirty whether they contained silica in combined torm rears' study of silicosis in the gold mining indus or no silica, produced disease in animals, nor and the s in the try and it was interesting to note how largely the was evidence of disease found among workmen observations concerning the etiology and clinical exposed to these dusts except in those instances It up a course of silicosis made in the early studies in where free silica was also present.* 1 hat the fail of pul this country had stood the test of time. Labora ure to find evidence of pulmonary disease among irei- un- tory researches which have been carried on in workmen was not due merely to lack of a suifi- dse pre- his and other countries have modified our earlier cientiv severe exposure was indicated by the uni was that ntaining "acted a fibrosis ; appearanied by in which ideas as to the manner in which silica affects the lung and have greatly increased our knowledge oi the pathology of dust disease. Modern roent genology lias made possible early and accurate diagnosis and also lias enabled tlie physician to watch the progress of affected individuals. I might state here that organic dust has not formly negative results in animals where llie conditions of exposure were Known and coni rolled and similar io those ol silica e.xposvres. X-ray films ol individual'- exposed iur a number ol ar to tiles''' inorganic dusts, winch contained n ree silica, mac show peribronchial thickening ae centiiatioii of die broiu inal tree. e siane ap V symp- been shown to produce a reaction of the pulinon- pearance can lie found hi individuals who have --i, tissue and the pronouncement of Landis never been employed in dusty' Industries ( Eea- oms pre- -| some twenty years ago that organic dusts played Talc in .Ac ex.fallen. SfC I'.S.I'.li.S. .dill \ I'M. MEDicm^|l : November, 19-10 777 ' - 4 P N E U M O C O N I O S I S --LANZA sionally x-ray films of some of these workers will show a diffused haziness or increased density that might be construed as due to the action of dust. However, these workmen are healthy and neither symptoms nor disability can be ascribed to this x-ray appearance. Hence, my opening comment that pneumoconiosis, as a generic term, has a limited importance from a clinical standpoint. Two specific and distinct types of pneumoco niosis are important, namely silicosis and ashestosis. Asbestosis is the exception to the general rule in that it is a silicate, a form of combined and not free silica, which does produce a charac teristic fibrous reaction in the pulmonary tissue and which mav produce disability and death. In animal experimentation, intraperitoneal injection of asbestos dust produces an inert reaction --that is, there is no cellular proliferation as is observed with the carious forms of silica. Inhalation ex periments produce a pulmonary fibrosis similar to that in human beings, with the curious anom aly that fibrosis did not result when the liner dusts were used. This has led Gardner to believe that the,; action of asbestos in the lungs is probably mechanical and due to the peculiar shape of the asbestos spicule and the constant movement of the lungs. Further support is given to (his theory" in that, unlike silica, asbestos will not produce its characteristic reaction in animals in other than the pulmonary tissue. Asbestosis first came into prominence in this country' about 1930, since when a number of in dustrial studies have been made. The symptoms are largely similar to those of silicosis hut the pa thology ami the appearance on an x-ray film are entirely different. The x-ray shows a diffuse haziness or ground [glass appearance, especially in tile lovcm half of the lungs; Modulation is altsent, and the factor of infection appears to be much less important than in silicosis, ai least that is our experience in this country. The total num ber of workmen exposed to asbestos dust inhala tion is very much smaller than for silica and strenuous efforts have been made by asbestos plants to control their dust hazard. Asbestos fab rication is a factory industry, largely textile in character, and the control of dust is less difficult than the control of silica dust in mines and foundries. Consequently, there has not been and probably never will be, the opportunities for the clinical study of asbestosis such as have been made possible by the wide variety and extent of j am silica occupations. j loc A small number of deaths from asbestosis have been reported and not all of these have been fl cut followed by postmortem. Mostly other organa' sili disease was also found or diagnosed, which tends vet to confuse the role of asbestos in these cases, but Tb in some cases death undoubtedly resulted from / uncomplicated asbestosis. J\ There has not been sufficient opportunity in field surveys of asbestos plants to acquire enough information to correlate the production of asbes tosis with varying degrees or intensities of dust exposure nor have the conditions of dustiness, as evidenced hy particle counts, run as high as in the more severe types of silica dust exposure. Vrt have had under observation for ten rears a small group of workmen with asbestosis. Sonic t'f these have shown a progression on their x-ray films. They are still working and in seeming good health. However, in the meantime the plant ha* been cleaned up and the dust controlled so we do not know what would have been their history had they continued to work under the former, pre sumably hazardous conditions. Our original concept of silicosis was based on studies of industries in which there was generally a more or less severe exposure to dust containing a high percentage of free silica. As industrial investigations came to include a wider variety ot industries, our concept broadened and underwent some modifications. The data gained in industrial surveys, -when correlated with laboratory find ings, cleared up a number of apparently conflict ing and puzzling observations. Not only did "e learn that the incidence and progress of silicosis in any location depended upon the amount of I, silica dust in the air and the length of exposure, ft but it was demonstrated that in many instances : other substances were present in the dust with the f I silica and that these substances modified the ac- jj. lion of silica. Furthermore, it was shown that H the action of silica was not due to its physical M properties but to its chemical properties. Also, J where certain substances had been accused of causing a pneumoconiosis, the olfending agent was in fact the silica which was also present. Metallic dust, for instance, which in the eariy writings had been considered as more, dageroui i than silica, was found to be relatively harmless. There came a better understanding of what caused the variations in the clinical appearai 778 M inneso ta M ebtciKS PNEV MOCON10 S!S--I.AN! i and course of silicosis as observed in different locations and in different industries. Men en: gaged in iron ore mining and in quarrying and cutting granite are exposed to dust containing silica-and other substances as well, which tend to retard the action of silica upon the lung tissue. The pathologic process is altered and the appear- ance on the roentgenogram is altered sufficiently ' for the experienced physician to distinguish one . type of exposure from another. With the mixed 1 dusts, the progress of silicosis is usually slower and when infection occurs, it tends to be more . chronic but the amount of tuberculosis found *: among granite workers and iron ore miners is ; nevertheless inordinately high. Cases have been ; reported of workmen exposed to dust containing f silica and caustic alkalies which produced a rapI idly developing and fatal type of silicosis with | early infection. ! On the other hand, certain industries have been | studied in which the silica hazard was found to | be of a degree which would not: produce disI aiding silicosis within the average working liie| lime. After forty or more years of such cx| posure, many workmen would show typical noclu| iation on the roentgenogram, but their symptoms 1 were few or absent and they were still working 1 every day, many of [hem being well over sixty I years old. All of this emphasizes how necessary it is to study' the etiological factors in ordc to arrive at a correct solution of the silicosis hazard jo a given location or in a particular industry. It also explains the apparently conflicting conclu sions that are sometimes drawn from isolated | cases of silicosis when the work condi!Am-, that is. the nature and type o f exposure, have not ibcen or cannot he determined. The pneumoconiosis of coal miners illustrates || yew well the modify ing action of one dust upon 'y anothcr. Miners' asthma had for years been recH o'mized by physicians in the anthracite industry If ;ls a definite clinical entity. It was difficult to be ll jievc. however, that coal, an organic substance, could produce a disabling pneumoconiosis. The Public Health Service made a thorough study of the anthracite industry in 1933 and the results ot this confirmed what many observers had susH n e tte d , namely, that disabling miners' asthma g| ,vas in fact, a silicosis; a form of silicosis mojii j e(] >y the combined action of silica and anthra cite dust, and to which the term anthraco-silicosis r.ighl justly be applied. The incidence and pvog- KovkmBtu;, 1940 ress of disability was, as in other silica dust haz ards, proportionate to the extent of dust ex posure, The silica was accounted for by the fact that the veins of coal lie between rock formations which frequently have a fairly high silica con tent, and, also, that there was some silica in direct association with the coal itself. Consequently, the workers had some silica exposure. Anthra cite mine dust varied in its silica content from about 11 per cent for miners working directly in coal to about 60 per cent for men working in rock, with various types of exposures falling be tween these two extremes. Pulmonary tubercu losis was associated with anthraco-silicosis to a very considerable extent. Below the age of thirty-five, hard coal miners showed an incidence of pulmonary tuberculosis slightly less than that found among male workers in general. In the age group of thirty-five to forty-four, the tuberculosis incidence was twice as great, and from forty-five to fifty-four, five times and above fifty-five about ten times the rate for all adult nude workers. Or, to express it in another way, clinical pulmonary tuberculosis was found in 13 per cent of those with early anthraco-silicosis and in 43 per cent of those in the more advanced stages. The x-ray appear auces. wink- sfinii; tr to iliC sili.'osis 0f hard rock. miners, ran usuai ly be 'li ien.aiti ate.'d troni the latter. \\ fill :`espeet U) hhu minons coal mining, the silica lac o r is a]Uitirem ly les- m r si eut or 1acking cm rei)'. A nimbi*r of s!Ufiies have 1oeen mafic Lv (lie Paoliie Health Sei*vkv ntil have not vet !n:Cit jinfilisi cd . Dea di cero heales Ol sot!- eoa! miiHTS V: ere anal) zed for a fiee-year period and showed, no appreciable difference, with respect to deaths, from tuberculosis, between the coal min ers and the farmers living in die same counties. Inhalation experiments with bituminous and anthracite cord (1.76 per cent SiO,, ) have pro duced a very slight read ion and anthracite dust proved inert on intraperitoneal injection. We may conclude that in the absence of silica, coal will not produce a specific fibrosis associated with disability. The relationship between pneumonia and sili cosis es not eniirelv clear. I'hc data obtained from various studies and from animal experimen tation are not always consistent. The high inci dence of pneumonia in some industries with a silica liazaid can not lie disassociated from ex- 779 PNEUMOCONIOSIS--LANZA posmv t'i extremes of heat or cold or both. Coal miner.; have a high incidence of pneumonia and it is a cnrnmoi] cause of death anion" the older men with nnthraco-silicosis. My own impression is that individuals with any considerable amount oi silicosis have a more unfavorable prognosis ni pneumonia than would otherwise be expected but tins experience is not very recent. It remains to be seen whether silicoltcs respond to specific serum treatment or chemotherapy as well as do those who do not have dust fibrosed lungs. Summary There is still much to learn about the action on the lungs of many kinds of dust. The effects of pure silica (S i0 2) have been demonstrated under many conditions in this and other coun tries with a high unanimity of agreement among investigators. Where the silica damage to the llirgs is extensive, the incidence of tubercle in fection is high. Where the silica exposure has been extreme, a tuberculous infection is almost in evitable, but every physician who has had wide experience with these cases has seen exceptions to th:is rule. T/xiay in American industry, severe exposures are uncommon. They occur mostly as isolated in stances as when a sandblaster has been working with faulty protection. Tubrculo-silicosis may run a very chronic course, but if the silica dam age is extensive, the progress may be fairly rapid, but many exceptions will he found to the general rule. We are acquiring a constantly broadened knowledge of the action of mixed dusts, that is, dusts containing other substances along with the silica, but the more intense the silica exposure, the more these cases run true to type. Naturally the clinical picture of silicosis is changing as in dustrial dust control becomes more and more perfected so that we may expect to see more and more of the type or degree of sinensis which is accompanied hv lithe disability. 1 am convinced, however, that where the reaction has proceeded to cause undulation, even though moderate m extent, a definite, increased susceptibility to h'" bcrculosis takes place. hinally, we must consider the criteria upon which the diagnosis of silicosis can he based. Undoubtedly, the early manifestation of silica dust: reaction is peribronchial ihickening v.utii an increase of the hilium shadows, as seen in a roentgenogram. The same mac be seen in work men exposed to dusts other than silica and in in dividuals who have never had anv sort ot dust exposure. Consequently, those of us who got together several years ago under the leadership ot l)r. Pancoast, felt that for practical purposes, a diagnosis of silicosis was not justified unless the specific reaction of nodulation, as found in ex perimental animals as well as in human subjects, was present. In addition to a characteristic film, there must be a history of exposure to silica dust adequate to produce disease. Where an industrial investi gation is being made, and the working conditions previously determined, it is usually not difficult to separate the silicotics from the non-si Hotics and usually the presence of infection can be rec ognized or ruled out, careful consideration being a given to the physical signs and the symptoms as well as the x-ray film. The isolated case that may turn up in hospital or clinic service may present considerable difficulty. Such patients are apt to be suffering from a combination of illnesses. They usually cannot give a sufficiently informa tive work history and even with a characteristic film, it may be difficult to say that a patient has silicosis (or even more difficult, asbeslosis) and to what extent his pulmonary condition may be responsible for his symptoms or his disability. 780 M innesota Medici - j