Document Yjk5k4gpvM74gGRyQJ1xk0ao0

THE OCCURRENCE OF PULMONARY FIBROSIS AND OTHER PULMONARY AFFECTIONS IN ASBESTOS WORKERS* E. R. A. Merewether, M.D. H. M. Medical Inspector of Factories INTRODUCTION He was treated in the Charing Cross Ho RIOR to the commencement of Pthis inquiry, in February, 1928, definite knowledge existed of pital for two months, and then returned work. After a few months, however, i became ill again, and was re-admitted to t.1 Hospital in April, 1900, where he died. T; only two deaths of asbestos workpeorsst-mortem examination confirmed ti about whom there was expert opinion that the inhalation of asbestos dust clinical diagnosis of extensive pulmona. fibrosis. There was no evidence of pulm nary tuberculosis, and examination of tt had at least contributed to, if not sputum for B. tuberculosis was negative. caused, the fatal outcome. The first of these, in retrospect the The second case was reported by D most suggestive, only came to light W. E. Cooke in 1924, eighteen yeai some years after the occurrence, when later (2): full information was unobtainable. * f * -* * s All that is known of this''base, now referred to as "the Montague Murray Case," is. contained in the evidence given by Dr. Montague Murray before the Departmental Committee on Com Tbe deceased, a woman, aged 33, wh died in 1924, had worked in asbestos for 1 years, but intermittently for the last years, owing to periods of ill-health. Tk post-mortem examination revealed, nc only extensive fibrosis of the lungs, but aU pensation for Industrial Diseases in much change due to pulmonary tuberculosa 1906 (1). From this source, we learn that: The patient, a male aged 33, came under the care of Dr. Montague Murray at the Charing Cross Hospital in the beginning of 1899. He bad worked with asbestos for Although Cooke (3) and Stuar McDonald (4) were conclusively of thi opinion that in this case the lung, showed a progressive dust fibrosis, to gether with a chronic tuberculous in "some 14 years," 10 years as a cardroom band, and the remainder in some other room of the factory, "where there was much less dust." He volunteered that, of the 10 people working in the cardroom when he went into it, he was the only survivor, and fection, the etiologic relationship be tween the inhalation of asbestos dus and fibrosis of the lungs would havt been strengthened by the absence of: tuberculous infection. that all the others had died somewhere about 30 years of age. There is no note as to the nature of his work, previous to that in the asbestos factory. Cooke's case is, however, of out standing importance, not only becaust of the discovery of "curious bodies' in the lungs--discussed later--but also Received for publication Feb. 17, 1930. and of more importance generally, be- THIS* pOCtfMW WAS NOT A RECORD OF PPG INDUSTWES/INC. DID NOT COME FROM IT'S fUES AND CANNOT BE AUTHENTICATED BY PPG INDUSTRIES, INC. I BB 0007171 | J. i.Tl May, LMv -" -- ------------- ft PULMONARY FIBROSIS IN ASBESTOS WORKERS 199 ^se its publication again directed attention to the possibility that inor ganic dusts containing little or no free silica may be productive of extensive pulmonary fibrosis. Of these dusts, the silicates form a very large class, of which asbestos is but one example. Many other members of the class, such as the feldspars, kaolin, French chalk, and pumice, are extensively used in industry. The importance, therefore, of delimiting the potentiali ties of the class as producers of pul monary fibrosis is clear. Cooke's case was the first to be generally reported in the medical press; the facts of the Montague Murray case, although contained in the evidence presented before the Departmental Committee in 1906, and published in 1907, were liable to be overlooked in the mass of important material on industrial diseases elicited u- that Committee. ince Cooke's case, Dr. I. M. D. ^Eieve has mdde a careful study of a - 'group of asbestos workers in his prac tice, and has courteously allowed access to his records. In February, 192S, Dr. MacGregor, Medical Officer of Health for Glasgow, drew my attention to an asbestos worker who was receiving treatment in one of the hospitals in that city. This case, the details of which have been reported by H. E. Seiler (5), pre sented, both clinically and radiologically, signs of a diffuse pulmonary fibrosis, with no evidence of a tubercu lous infection. On further investiga tion into the patient's industrial and medical history, no presumptive cause, other than the inhalation of asbestos dust, was found to account for the existence of the fibrosis. This case, at that time the third of which the Factory Department had knowledge, was, however, the first in which the four essential conditions, necessary to establish a relationship between the inhalation of asbestos dust and the development of fibrosis, could be demonstrated. These conditions are: 1. Work involving exposure to asbestos dust. 2. The existence, demonstrable clinically and radiologically, of a definite pulmonary fibrosis. 3. The absence of previous or present in fections known to cause pulmonary fibrosis --e.g., tuberculosis, influenza, or pneu monia. 4. The absence of previous or present work involving exposure to other dusts, which might cause pulmonary fibrosis. These conditions being fulfilled, a relationship between the inhalation of asbestos dust and the development of the pulmonary fibrosis may be pre sumed. - . The importance of establishing whether the supervention of this dis ease in an asbestos worker was an exceptional occurrence, or evidence of a grave health risk in the industry, was now apparent, and steps were taken, forthwith, to obtain prima facie evi dence in proof, or disproof, of the exist ence of such a risk. A number of workers in. asbestos were selected and examined clinically and radiographically. The findings invited further investigation through out the industry, with the result that a comprehensive inquiry involving the investigation of the different processes in relation to the evolution of dust, and the examination, both clinical and ra diologic, of workers, was undertaken during the year 1928, commencing Vol. It No. 4 Q CO tt-v*: * . v-r * UJ --' ; !-- : OO : C IQ J I !J with the carding, spinning, and weav and any methods of ventilation whicl ing processes of the industry. had been found of especial value. In the meantime, in March, 1928, The result of this investigation di< the death of an asbestos worker (one of not conclusively prove that asbesto Dr. Grieve's cases) occurred in another possessed injurious properties, but i part of the country, and, on post pointed to the probability that sue: mortem examination, a condition of was the case. It is interesting to con widespread fibrosis of the lungs, with sider why it was that no conclusive out tuberculosis, was revealed. The proof one way or the other could b< microscopic examination also disclosed obtained, then, as to the injuriousnes. the presence of the curious bodies. of asbestos dust. Some, if not all, o In 1928, also, Dr. F. W, Simson (6) the factors which affected the positior reported a fatal case of fibrosis of then are, in varying degree, continu the lungs occurring in a native work ing factors, and have an importan- ing in an asbestos mill in southern bearing on the present inquiry. Thei: Rhodesia. operation, while providing a solutior In order that this brief survey of the to this query, also affords an explana events leading up to the present in tion to another pertinent question quiry may be complete, it is necessary Why is it that this industry, foundec to review the investigation made in in antiquity, has only recently excitec 1910 to 1911 by Dr. Collis and Miss attention, by reason of its raw materia Whitlock--the only previous inquiry becoming suspected as a cause of indus into the subject. trial disease? ' . _ In May, 1910, the Registrar-Gen-, * The answer appears to be that in the eral drew attention to a death which past it was not practicably possible tc had been certified as "acute pulmonary obtain proof of the injuriousness of phthisis in an asbestos worker," and asbestos dust, considering the limita to a statement (for which he was un tions imposed by the state of the indus able to vouch) that seven other deaths try, and the point reached by research from phthisis had occurred in the same work into the relationship between factory. dust inhalation and diseases of the Following this, extensive inquiries lungs. were made, a medical report on all the The industry itself, not a large employees in the factory concerned one today, was then (1910) consider was obtained, and Dr. Collis and Miss ably smaller. Certainly it had begun Whitlock investigated generally the to grow rapidly, but the number of various processes in the industry with workers who could have been employed respect to the evolution of dust, for a period of time long enough to methods of ventilation, lost time due to allow of the development of definite sickness, etc. Also inquiries were physical signs of pneumonokoniosis made of the Canadian government as must have been quite small, and dis to the conditions in the asbestos persed over the country. quarries and mills in that Dominion, Precise knowledge of the morbid evidence of increased sickness and affections of the lungs produced by the mortality rates among the workers, inhalation of dusts was more fragraen- CG IGib? J. r. n. May* W3d F ** PULMONARY FIBROSIS IN ASBESTOS WORKERS lj than it is today. The position was clearly stated two years later in evidence placed before the Royal Com mission on Metalliferous Mines and Quarries. This Commission, when re porting in 1914 (7), stated "we do not know whether other dusts besides those containing free crystalline silica induce a pathological condition in the lungs, though the experiments of Professor Beattie in animnlg suggest that this may occur/' It is only in the last year or two that research has produced some definite evidence as to the precise effects of some of these dusts on the lungs (8) (9) (10) (11) (12). In 1910, radiography of the lungs, in both its technical and its interpretative aspects, was still in its infancy and, eo far from having attained its present status of being an indispensable aid to the diagnosis of the dust diseases of the lungs, was an unused ally. Tn addition, the existence of a mcasjf exhaust ventilation in the most wKty-processes of the industry, incom plete as it was, bad important results in modifying the onset, course, and duration of any pathologic lung condi tions resulting from the inhalation of the dust. This influence has been much more pronounced in the period intervening between 1912 and the present inquiry, and will be referred to again. Another factor which has tended and - still tends to obscure the possible deleterious effects of the non-silica dusts, is the general use of the phthisis mortality rate as a comparative index of the degree of injuriousness of the dust encountered in the various dusty occupations. This rate, while of great value in separating dusty industries into two great groups--those which show an excess mortality from phthisis, and those which do not--as well as being a comparative index of the in dustries belonging to the former group, not only is of little value as a means of classification in the latter group, but also tends to distract attention from it,, and to result in the associated dusts be ing dismissed as more or less innocuous. Evolution of dust is only one factor, though an important one, which may cause variations in the phthisis mor tality rate in different industries. Wages, hours of work, aggregation of workers, amount of food, housing, and other social and environmental condi tions are, however, powerful influences in the same direction, and are not necessarily comparable as between the workers in any two industries. In thus reviewing some of the influ ences which have retarded recognition of the baneful effects of some dusts upon the lungs, the singular attributes of pulmonary fibrosis, the most impor tant of the diseases oaused by*the in halation of dust, must not be over looked. This disease, insidious in its onset, stealthily advances with but faint warnings of its progress; inexorably it cripples the essential tissues of the lungs, yet for a considerable period causes almost no inconvenience to the worker. As time goes on, however, the lungs find more and more difficulty in re-aerating the blood; and breathing is quickened on slight exertion. Still the worker is able to remain at work, but is aware of his undue shortness of breath on extra effort. Usually, how ever, he ascribes it to causes other than the dust he is inhaling. As the disease progresses, if no acute illness has caused a fatal termination, Vol.Il No. 5 9 NOTE: THIS DOCUMENT DID 202 THE J' a stage is reached when the lungs can do little more than maintain life; and the shortness of breath is extreme. Even in its terminal stages, the disease, deceitful to the last, may masquerade as chronic bronchitis, pulmonary tu berculosis, bronchopneumonia, or the like. While more or less acute cases of fibrosis closely simulating miliary tuberculosis have occurred, even in this country (13), they have all been asso ciated with the inhalation of dense concentrations of free silica dust, and are, fortunately, the exception rather than the rule. The difficulty of diagnosing pulmo nary fibrosis, especially in its early stages, or if complicated by tubercu losis, has been stressed by a number of authorities, and has, undoubtedly, con tributed to impede the attainment of precise knowledge of the extent to which the various industrial dusts affect the lungs. Difficulties and obscurities still im pede, though to a less degree than in the past, any investigation into the effects of an industrial dust upon the lungs of those exposed to it; but prior to the War, although there were certain slight indications that asbestos, in common with some other dusts, might produce permanent pathologic changes in the lungs, it was not possible to obtain evidence sufficient to prove or disprove this hypothesis. At the outset of the present inquiry into what, if any, pulmonary diseases workers exposed to the inhalation of asbestos dust are more prone to con tract than the general population, it was considered essential to view the problem afresh, and with complete detachment, because of the fact that asbestos dust has a totally differ physicochemical constitutionfrom tl of dusts containing much free silicas causing silicosis. It was felt tl although much valuable guida: could be obtained from the metht of investigation of silicious dusts, c had to be taken to keep an open mi so as not to be unconsciously bia in the direction of assuming that effects of the dust, if any, must be cc parable in some degree to those crystalline silica. Asbestos and the Asbestos Industrt Asbestos The term asbestos is a collect name, of no definite mineralogic . nificance, which has been applied t variety of silicate minerals, which di from one another in chemical com sition and physical properties, which resemble one another in tl finely fibrous feature and flexibi (14). Their value depends on facility with which they are capabl being split up into long and flex: fibers, which can be spun like cot and woven into cloth; on their res ance to heat and acids; and on tl insulating properties with respect heat and electricity. Varieties of asbestos possess tfc qualities in differing degree. G mercially, therefore, selection is m by the manufacturer of that var: and grade which is most suitable the purpose in view, regard being j to ordinary economic factors, sue': the cost of the raw material, and price which the finished article ma; expected to command. Consignments of asbestos of same general variety, but with di j. Mi) j**BB 0007175^ PULMONARY FIBROSIS IN ASBESTOS WORKERS 203 ent countries of origin, are frequently mixed in the preliminary processes of manufacture. Thus Canadian chrysotile may be mixed with Russian, or Rhodesian chrysotile, and so on. Less frequently, totally different varieties, such as amosite and chrysotile, may be mixed. Practically speaking, all that goes under the name of asbestos, in com merce, is either fibrous serpentine or a fibrous mineral of the amphibolc, or hornblende, group. The former is the most important commercially; but strictly, the mineralogists confine the bined water, and usually more cal cium, aluminium, and iron. Members of this group are resistant to acids, but arc more difficult to spin, some being quite unsuitable for this purpose. The most important members of this group are crocidolite, amosite, and tremolite. Crocidolite and amosite are mainly silicates of iron, the former having a beautiful lavender-blue color, thelatter being brownish-gray. Both are spun and the yam is woven into cloth for various purposes, such as acid filter ing, and for making into insulating TABLE 1.--COMPOSITION OF SERPENTINE AND AMPHIBOLE VARIETIES OF ASBESTOS MINERAL GBOO? YARIETT SiO, percentage or AljO* FeO FejOi Com MgO C&O Na,0 KiO bined Water -- ^'entine Chrysotile 39-42.5 0-3.7 0.7-4.4 39-43 0^3.35 13.3-16.5 ^Thiboie- Crocidolite 50.5-52.1 0-1 35.5-37.4 0-3- 0.75 6.2-9 * * 1.6-4.5 Amosite 48-53 1.2-9.4 34-44 0.7-6.4 * * 4 0-2.5 2-3:8 blende) Tremolite 57.2 0.9 3.2 22.8 13.4 0.6 0.3 2.4 term asbestos to fibrous forms of horn blende. These two types arc sharply distinguishable, chemically and roiner-alogically. j Serpentine asbestos, or chrysotile, is a hydrated magnesium silicate, con taining practically no calcium, a high percentage of combined water, and a low percentage of iron. This variety is very suitable for spinning, but is attacked by acids. Nearly 80.per cent, of the world's production of asbestos is derived from Canada, and is of this variety; the remainder comes mainly from South Africa and Russia. The amphibole, or hornblende, vari eties contain less magnesium and com- mattresses, as well Os for other pur poses. Both are produced extensively in South Africa, from which quarter all required commercially is obtained. Amosite, a comparatively recent dis covery, is found there in very large deposits; its use is steadily increasing, the initial difficulties associated with the manufacture of textiles from this variety having been overcome. Tremolite, found in various quarters of the world, has been mined in north ern Italy since the time of the Romans. Its chief use is in the manufacture of asbestos millboard and for filtering purposes. Table 1, compiled from various Vol.12 No. ( { BB Tsssumr HOTETHiSDMU^'^ -- MOT COMti^vi r ` r THE JOURNAL 0 USTRIAL HYGIENE ~ sources, shows the main differences in the composition of these four varieties. Only a very small proportion of the world's production of asbestos, which is between 300,000 and 400,000 short tons per annum, is suitable for spin ning, and the most desirable grades of spinning fiber, consequently, command a high price--now over 100 a ton. The shortage of this grade has led to improvements in manufacturing proc esses which have enabled less expen sive grades of fiber to be utilized for spinning, some of which give rise to an increased amount of dust. About four-fifths of the world's pro duction of asbestos is fiber unsuitable for spinning, and this is used in the manufacture of asbestos millboard, tiles, sheeting, paper, and many other articles. It is the discovery of indus trial uses for these very short fibers, and the dust-like waste, which has been responsible for the phenomenal expan sion of the industry as a whole. The spinning and textile section has also shared, because of the extensive use of the yarn and cloth in the manufacture of steam packings, insulating mat tresses, brake linings for motor cars, fireproof curtains, and the like. In 1S80, three years after the dis covery of the large Canadian deposits, the world production of asbestos was little over 500 short tons; by 1900 it had risen to about 35,000 short tons, by 1920 to over 230,000 short tons, and by 1925 to over 330,000 short tons (15). The imports of asbestos (all grades) into the United Kingdom rose from 18,591 tons in 1922 to 33,520 tons in 1927 (16). The figures for 1927 refer to Great Britain and northern Ireland only. Of these quantities 8,844 tons and 3,794 tons, respectively, were reexported. Thus the consumption of asbestos in this country trebled within five years. The Industry On considering the uses of asbestos one is astonished, not only at the wide range, of articles manufactured from this mineral, in greater or less propor tion, but also at the diversity of indus tries which nowadays find its use necessary, either in the form of the raw material, or as manufactured articles. Evidently, therefore, with the multi plicity of processes and dusts encoun tered in the ramifications of the indus try, discrimination would have to be exercised, and some limit set to the processes included in the inquiry. The processes selected may be divided, roughly, into 1. Processes involving the manipulation of asbestos, either pure, or admixed with a small- proportion of cotton, or other vege table fiber. - 2. Processes involving the manipulation of asbestos together with other dusty ma terials. 3. Processes involving the making up of asbestos cloth into other articles. Group 1 entails exposure to asbestos dust mainly, and to cotton, or other vegetable dust, very slightly; group 2 entails exposure to asbestos dust in very varying amounts, and also expos ure to divers other dusts, such as brick dust, magnesia, kieselguhr, fossil meal, and cement; in group 3 the exposure to asbestos dust--provided no other as bestos processes are being carried on in the vicinity--is, in the majority of cases, negligible. Processes belonging to all three groups may be carried on in the same factory, and workers may transfer from one department to another (30). 1 BB 0007177 | J. I. IT. Hay, 10.10 GG r_ / *55jw.-guwaeMw. uniwjwwaitgw ww PULMONARY FIBROSIS IN ASBESTOS WORKERS 205 * i V f *. *] issn : iWt-1 . -if . investigation into the intricate ques tion of the effects of mixed dusts, while possibly productive of some, general corollary, would lose much of its value in the absence of knowledge of the effects of the several component dusts, and moreover would introduce an in calculable variable into the final results. For these reasons, and also because the Montague Murray case, Cooke's, Grieve's, and Seiler's cases all occurred in processes included in group 1, it was considered advisable to exclude, as far as possible, from the inquiry all workers exposed to the in fluence of mixed dusts, and all those not employed in processes included in groups X and 3. The processes included, therefore, are the crushing, preparing, sieving, opening, mixing, carding, spinning, doubling, plaiting, braiding, and weav ing of asbestos, together with the ooerations incidental thereto. Also uded is mattress making, where the '^Bng is asbestos, and the manufacture of some insulating materials, whese the dust produced is asbestos. The carding and spinning processes have many points of resemblance to the corresponding processes in the cotton industry, but with essential modifications and restrictions caused by the different physical characters of the asbestos fiber. These processes are aided by an admixture of cotton, or other vegetable fiber, and usually from 2 to 10 per cent, by weight of cotton is added. More rarely, and for special purposes, long-fibered asbestos is carded and spun with no admixture, of vegetable fiber, but usually asbestos yams contain a core of either cotton or metal wire. -- Asbestos yams are not only used for the weaving of fabric^, which them selves are used for a multitude of pur poses, but, braided together, are made into ropes for use as 6team packings and other purposes. The interstices and center of the rope may be filled with other materials such as talc, oil, or graphite, depending on the precise use to which the rope is to be put. Asbestos mattresses, used for blan keting steam engines, and for other insulating purposes, are made of asbes tos cloth stuffed with asbestos fiber. The stuffing material may be, however, slag wool, magnesia (containing ap proximately 15 per cent, of asbestos fiber), or kieseiguhr with a small per centage of asbestos fiber. The man ufacture of mattresses filled with mixtures of asbestos fiber and other materials has not been included in this portion of the inquiry. The shortness, slipperiness, and lack of strength of the individual asbestos fiber, as compared with cotton, flax, wool, silk, and other textile fibers, have been the cause of much technical diffi culty in manufacture. The efforts of manufacturers to cope with these diffi culties, together with those due to wide variations in the physical properties of the raw material, are reflected in the methods employed by each. For these reasons, and because of the great num ber of patented and special products manufactured, one finds considerable differences in detail in the processes in use. The majority of the processes men tioned result in the evolution of dust, although by no means to the same extent. Differences in plant, quality of asbestos used, methods of manufac ture, type of finished article, and extent of application of exhaust ventilation, o CO ea y 5-- o to '?W ' ,4 &L m IS Js* s 5 >` m r- : a"n rU* S-.'waJ -0 *'; 5 ' |;? 2: m -5'. ' sm &SST ' XoST'tiB Til VoL No. i "bbT 0007112.1 : yj 5:187 NOTE: LI' f\ .'l * D '206 C'q ;*o all result in variations in the evolution of dust in similar processes in different factories. Variations in the evolution of dust in different processes being of outstanding importance, a series of samples of dust from the air of workrooms was col lected, by means of the Owens jet apparatus. Pcrpulaiion ai Risk.--A calculation of the total number of workers employed in the processes already enumerated as TABLE 2.--DISTRIBUTION, ACCORD ING TO LENGTH OF EMPLOYMENT, OF (A) 775 WORKERS ENGAGED IN ASBESTOS PROCESSES AND (B) SELECTED SAMPLE OF 363 WORKERS (A) (B) TBS. EMPLOTtJD t E** X z 8 a o 6 z u 04 6 z 104* 0-4.............................. 483 62.3 89 24.5 5-9............................... 200 25.8 141 38.8 10-14............................. 51 6.6 84 23.2 15-19............................. 21 3.1 28 7.7 20 and over......................... 17 2.2 21 5.8 Total.................................... 775 100.0 363 100.0 included in this inquiry, but excluding those engaged in processes included in group 3 in which the exposure to as bestos dust is negligible, gives a figure of approximately 1,000; if we could add to this the number of workers engaged in handling pure asbestos fiber only, in the preliminary stages of the processes included in group 2, we should obtain the total population at risk from the effects of asbestos dust it self. Unfortunately, this latter figure is unobtainable; but a rough estimate, and most probably an overestimat is 600. Thus, about 2,200 appears t be the total population at risk in th country, for the purposes of this ii quiry. This figure, however, does nc include the large number of worke engaged in the processes in group which involved exposure to the mfl: ence of mixed dusts, of which asbestc is but one, and commonly not mo: than 20 per cent, of the mixture. This estimate of the population : risk, although it may be excessive, useful, since it enables us to judge < the adequacy of the sample of worke examined, and to apply more correct the incidence rates of any pulmona: affections disclosed by the examinatic of the sample (30). The sample examined (after eleve cases are excluded of fibrosis and pr fibrotic conditions due to causes pth< than the inhalation of asbestos dus; numbered 363, representing 16.5 pt cent, of the population at risk, est mated as above. The manner t selection of the sample must be referre to, since just interpretation of tt results depends upon a due appreci: tion of the relationship of the sample t the whole population at risk. The principle of selecting primaril those longest employed was adopter but regard was also paid to the othf end of the scale, so as to obtain info: mation as to the length of exposure t dust necessary before effects are man. tested, and also as to the particuk process in which the worker wr engaged. It was felt that, in this wa; the maximum information would t obtained in the shortest time. Table 2 shows the distributior according to length of employmer (not necessarily in ono factory), i j. 1.1 Hay. w 1 BB 0607179 | Mti PULMONARY FIBROSIS IN ASBESTOS WORKERS 207 i workers engaged in the processes a center which is equipped with the under review, and of the sample of 363 necessary N-ray plant, and where the workers, distributed in the same way. services of a consultant versed in the The enormous preponderance numeri science of radiography of the lungs are cally of workers employed under five available. Furthermore, it must not years in these processes is striking, as be overlooked that such examinations is also the very low percentage of are voluntary, and not, as in South workers employed ten years or longer. Africa, compulsory. Moreover, re Comparison of the two parts of the peated and protracted examinations table shows that the effect of this only result in the exhaustion of all method of selection is that the number concerned, and much depends on the examined in each succeeding five-year willing co-operation of employers and employment group is a progressively employees, since the only incentive is greater proportion of the total number a desire to further the common welfare. which could have been examined in Radiography, therefore, has a differ each particular group. With a soli ent function in these inquiries, than tary exception, all those examined were when it is applied to individual cases at work on the day of examination. for compensation or other legal pur Not only the value, but the neces poses. .This function is not that of sity, of radiographic examinations of replacing careful clinical examinations, the chest in investigations into the as has been recently foreshadowed (IS, effects of dust upon the lungs, has been p. 40), but primarily that of being emphasized repeatedly by Watkins- an indispensable aid in diagnosis, Pitchford, and reaffirmed by the especially of doubtful cases, in the partmental Committee on Compen- determination of complicating lesions, tion. for Silicosis (17). A high in measuring the extent and progress standard of radiography is essential; of the disease, in locating the point at as Watkins-Pitcbford phrases it, the which the earliest radiographic signs radiograms must be "technically satis appear, and finally as a check upon factory." Indifferent films are useless, the human factor presented by the since it is the fine detail of the lung examiner himself. which is being studied. The examinations (except one) were In a general inquiry, such as this, carried out at each factory, in a room which involves the examination of set apart for the purpose, suitably workers in factories, large and small, warmed, and with the necessary scattered over the country, it is not appointments. On occasions the noise practicable, nor is it necessary, con of traffic or from the adjoining factory sidering the special purposes of the was a hindrance, but in one way or inquiry, for radiograms to be taken of another these difficulties were over all the workers examined. The dislo come or minimized. cation of work in a factory, caused by All the selected workers were exam the absence of a number of hands for ined by the writer. At three factories, this purpose, cannot be viewed with however, a number of workers were unconcern, especially when, as is not examined jointly with Dr. E. L. Middleinfrequent, the factory is remote from ton. His far-reaching experience of the c S'f# I*iff? ;c n *' fZ-L I-- --j.. r? Ts ' Zj c-Tx *i1*t>-;' tint *4* : X - .M-ii w -.w* > &.T$! ST*. WI gi-T VoI.lI No. S --__ ____ri_iij-__ .* gjfi lI BB 0007130~7 5 O' J r:! 69 208 THE JOURN^JQF iNDUSTElAL' HYGIENE "- * pathologic changes in the lungs, pro duced by the inhalation of various dusts, was of great value, and his assistance was much appreciated. Every effort was made to complete the clinical examination of the workers before the onset of winter introduced difficultly* due to ephemeral bronchitis, colds, and influenza, which would tend to obscure the main issues. Thus the clinical, and two-thirds of the radiographic examinations were completed by the middle of November, 1928, prior to the commencement of the influenza epidemic early in 1929. Clinical Examination Percussion The inhalation of asbestos dust originates changes in the lungs, which be looked upon as a measure of the efforts of the living tissues to repel, or incarcerate, the irritant particles of dust. These changes modify the per cussion note. It is true that the note elicited may be similar on both sides, but the note is not normal. It is thinner and higher pitched than nor mal, and there is a sense of resistance imparted to the plexor finger. In other words there is a diffuse, but slight, impairment of resonance. This alteration in the percussion note, however, is more difficult to recognize because it is bilateral, and extends over a wide area; consequently the aid of contrast percussion is denied. It is best elicited by rapidly, and very lightly, percussing the back of the chest from apex to base on each side. It will be found that the extreme apexes remain clear, but below the apexes the impairment is general. It increases over the root areas; below these, it diminishes in intensity, b> still persists. In other words, we fir tacked on to the paravertebral dulne an area, above and below, of impairt resonance, which is much more exte: give than that usually associated wit old inactive hilar tuberculosis. Impairment of the percussion not was found to be constantly mot marked in the right side; in fact, at fir. it was thought that in the earlie degrees of fibrosis it was confined i that side, but later, and more extende observations lead to the conclusic that the earliest detectable cases a: bijateral, although the signs on the le side are tenuous. This change is so constant that it h: been adopted as the most reliable sing clinical sign presented by this type c pulmonary fibrosis,, and no case h: been classified as fibrotic in its at sence. . Considering the frequency wit which signs indicating what may t termed "enlarged roots" were found i asbestos workers, it may be that parr vertebral dulness is one of the earliet signs produced by the inhalation c asbestos dust, indicating congestiv changes in the root areas and a chokin of the lymphatics with dust. Refle impairment of note, due to irritation o the lung tissue by dust, is, however, a; attractive explanation. It does no follow, of course, that workers present ing these signs will ever develop a defi nite asbestos fibrosis. Clearly, the physical signs presenter by any case of diffuse pulmonary fibre sis not only may be modified b changes produced by some intercurren lung disease, but, ab initio, will var according to the state of the lungs be fore the onset of the fibrosis. Time C-G I b 190 | BB 0007181 J j. 1.1 May, 10: ----- ^` < ~ ~ ' m Jpff PULMONARY FIBROSIS IN ASBESTOS WORKERS 209 the fibrosis may be implanted upon a to healed tuberculosis. That there is perfectly normal chest, in which case an extensive fibrosis is clear enough, the problem of diagnosis is straight and that most of it is not due to asbes forward. In other cases, however, tos is strongly suggested when examin preexisting root changes, so common in ation of the lower portions of the lungs an industrial community, may be pres shows that they arc comparatively ent, or the lungs may be already the slightly affected. Further help in seat of emphysema and chronic bron these cases, of course, may be obtained chitis, or of definite old tuberculous from the history and symptoms. lesions, or there may be a massive The third type, also rare, is that in pleural thickening, the result of an old which changes following an old massive pleural effusion. All these examples pleural effusion on one side so obscure . have been noted in the present investi the physical signs of any dust fibrosis gation, and others will readily come to as to render that side useless clinically mind. for diagnostic purposes. If the side Although in most of these cases the affected by the pleurisy happens to be dust fibrosis, if moderate in degree, can the right, the radiographic picture is be confidently diagnosed, especially also curtailed by the normal partial with the aid of radiography, it must be obscuration of the left lung base by the admitted that the problem becomes heart shadow. very difficult when the dust fibrosis is These three types were, with the comparatively slight, and the changes possible exception of the first, uncom produced by other conditions are pro- mon, and are mentioned merely to call uinced and diffuse. Three types of to mind some of the ways in which an fJL-; ^V*iese &&& have caused most difficulty asbestos fibrosis may be- masked, in 1 among those examined; fortunately, greater or less degree, by changes due numerically they were few. to other disease. . 1 The first of these is where the dust Only passing reference need be made fibrosis has been implanted upon lungs to the other physical signs found in the already emphysematous. It seems asbestos fibrosis, since they do not that, at any rate in the case of the differ materially from those presented asbestos fibrosis, until the fibrotic by silicosis. Chest expansion is dimin changes get the upper hand, clinical ished and may be reduced to one-half diagnosis of the fibrosis in these cases inch or even less in advanced cases. is impossible. Nevertheless, although Retraction of the apexes is common, the problem of the diagnosis of a and sometimes shows a peculiar feature fibrosis implanted upon an emphy differentiating it from that found in sematous chest has caused some diffi fibroid phthisis. Instead of the im- culty in this inquiry, it seems likely Japbile and sunken apexes seen in the that it can arise only under exceptional latter diseasepthc apexes are seen to circumstances. descend during inspiration, and to rise The second type of case which has again during expiration. This seems been a source of difficulty in clinical to indicate the anchoring of normal . diagnosis is that in which there are apexes by fibrous tissue in the lower extensive bilateral fibrotic changes due portions of the lungs. Some confir- Volll No. s . Jl L'. i *'J 210 THE JOURNAL cq lILtO raation of this was obtained radiologically. Auscultation In the majority of the coses of fibrosis, the respiratory murmur is weakened, much or little, generally, more on the right side, and often still more at the base; the expiratory sound is weaker , than the inspiratory, and often becomes less and less audible as one approaches the bases. Transitional phases between this and harshened breath sounds and pro longed expiration are not uncommon, even in the same chest. The latter may be noticeable in the upper por tions of the lungs, but progressively diminish toward the bases. Other combinations were also noted, how ever. The dry character of this type of fibrosis during most of its course is rather striking. Scattered fine rdles and clicks in the root areas, axillae, and bases were not infrequent; slight edema of the lower halves of the lungs was noted in one of the more advanced cases; but in a number, no adventitious sounds at all were heard. Pleural crepitations, and rarely a slight pleural rub, were noted--these attacks seem to cause little pain--and in one case a little fluid at the right base. No doubt this variability in the sounds heard on auscultation reflects underlying changes, temporary or permanent, in the lung, and is depend ent, inter alia, on the extent of the fibrosis with its associated pleural thickening--changes due to past dis ease, catarrh, or other intercurrent affection, and to the degree of compen satory emphysema present. Symptoms "' The symptoms exhibited by thes< cases of fibrosis, as might be expected closely resemble those of silicosis The distribution of the main symp toms, and of one sign, cyanosis, whicl is included with the symptoms for con venience, is given in Table 3. A fen cases have been excluded on the grounds that one or other of the symp toms complained of might be assignee to causes other than the fibrosis, suet TABLE 3.--DISTRIBUTION OF FOUR COMMON SYMPTOMS, AND OF CYANOSIS, AMONG CASES OF FIBROSIS 6TMTTOil Couch................. ...... Cyfinonifi. .................. HvAnnhA....................... ... Expectoration.............. Pain............................... a CASES IX u 2*a4 WHICH sriirroir < WAS PRESENT y. w o' X Per No. Cent. 91 54 59.3 03 52 55.9 91 47 51.6 01 31 34.1 94 10 10.6 1 Excluding those in which the presence of the symptom is referred to other causes. as a complaint of shortness of breath in a case with a past history of mild thyroid intoxication, or of dyspnea associated with obesity. Between 50 and 60 per cent, of the cases complained of cough, or of short ness of breath on slight exertion, or showed some degree of cyanosis, whereas only about one-third com plained of expectoration, and onetenth of pain, or discomfort, in the chest. Also, while 14.6 per cent, of the cases had no complaints and showed no cyanosis, and only 3.-1 per j. r. lr. y..iy, rj:i* I BB 0007183 I PULMONARY FIBROSIS IN ASBESTOS WORKERS 211 cent, presented all four complaints and find asbestos dust irritating, but to were cyanosed, 60.6 per cent, presented this day cannot work with a cotton two, three, or four of the five items. scutcher (as he occasionally does) with Clearly, none of the four complaints, out precipitating a coughing attack or the presence of cyanosis, can be an within an hour or two. Although he infallible indication of the existence suffers from winter cough and some of fibrosis; but the presence of two of shortness of breath, he stated that his them, shortness of breath on slight health has been much better since the exertion, and cyanosis in some degree, change. in an asbestos worker, is highly sugges Asbestos dust, therefore, has only tive, in the absence of other evident very mild powers as a reflex irritant of ' cause. the upper respiratory tract, and is, in Nevertheless an advanced degree of this respect, comparable to free silica. fibrosis may be present, and little com This is an unfortunate attribute, since plaint made. Symptoms, unless dis it leads to the assumption that the dust tressing, are so often a function of is more or less innocuous. the introspectiveness of the patient. The second type of cough is more Slight degrees of fibrosis, too, give rise intimately associated with the develop to no symptoms, in the absence of ment of fibrosis, and occurs, or perhaps an intercurrent bronchitis, since the is noticed, after a varying numbor of remaining sound lung tissue is' still years' work. Usually it is present only 'ply sufficient for all purposes. in the morning on getting up, when .Sough was the most frequent symp- after rather a sharp attackof. coughing, m, and was of two types. For* few a little viscid sputum "like an oyster" weeks after commencing work in a is brought up. A similar bout may dusty process, asbestos workers often occur at night after ceasing work; at find the dust irritating, and cough times it is sufficiently sharp to cause while in the dusty atmosphere; this retching. It is generally rather worse lasts for a few weeks, and then usually in winter, and may be noticed only disappears. The writer has noticed then. Although it closely resembles this effect on himself, but only while in smokers' cough, its features are pre a very heavy cloud of asbestos dust. cisely the same in nonsmokers. The dust seems to be only slightly Persons giving a history of cough irritant in this way. One or two men dating from an attack of pneumonia or who had previously worked in cotton other illness in childhood, almost in card rooms, or blow rooms, and were variably state that the cough has not affected by that dust, stated that they become worse since working with were unaffected by asbestos dust. asbestos. One worker succinctly de Certainly asbestos dust does not cause scribed the cough as "first in the asthmatic attacks like those seen in throat; later catches the chest." cotton card room workers. One man, Generally, this cough causes very who migrated from a cotton card room little inconvenience and may pass un "("hard waste") nine years ago to an noticed until the development of some asbestos card room, on account of the other symptom directs attention to the irritating effect of the dust, does not general state of health. Thus, out of ,n l-5 ' 212 THE JOURNALSIN^WtIHA!L!H^GIEftSU ^,LI: sixty-six cases of fibrosis, in thirtythree (50 per cent.) the cough was stated to have preceded the onset of shortness of breath, in twelve (18.2 per cent.) to have developed contempo raneously, and in twenty-one (31.8 per cent.) was either not noticed until after the onset of shortness of breath, or, although the latter was complained of, cough was not admitted. Complaints such as "colds go to the chest," and "frequent colds on the chest," were not uncommon. Com plaint of spitting of blood was excep tional; and in all cases in which this complaint was mentioned, the exciting cause was, primarily, some disease other than the fibrosis--e.g., in one, it was due to pulmonary tuberculosis; in another, it occurred only during a prolonged attack of pleurisy; and in a third, the hemorrhage was gastric in origin. Cyanosis, a valuable sign when present, rarely amounts to more than a duskiness, or slight blueness, of the lips; it contrasts, however, with the general pallor of the face with which it is often associated in these cases. Cyanosis in some degree was noted in 56 per cent, of the cases. It may be absent even when there is a consider able degree of fibrosis, or it may come and go. Pain in the chest is rarely com plained of, and then it is usually de scribed as "tightness of the chest," "soreness," or "aching." It was noted in 10.6 per cent, of the cases. Well-marked clubbing of the fingers was noted in a few cases. The general nutrition is hardly affected, except in the latest stages. Only ten (10.5 per cent.) were noted as being thin. In one, the nutrition was very poor; in twenty-one (22.1 per cent.), fair; and in the remainder of the cas good. Radiography Radiograms of the chest were < tained of 133 workers, or 35.5 per ce of' the number examined clinical Of these, over 100 were taken by I E. W, Twining of Manchester, a Dr. N. Tattersall of Leeds, and t remainder (except one) by Dr. F. Henderson of Glasgow. To all thr I am much indebted. Dr. Twin! and Dr. Tattersall have devoted ma hours to the joint study with the wit of the radiograms, and have dra freely on their wide experience of ra ography of the chest in furthering t purpose of the investigation. Dr. R. S. Paterson of Manchest too, added his, experience to a fir review of the films, and Dr. E. Barck now of Cambridge, lent his assistac in interpreting some difficult filrr to both, grateful acknowledgment made. The standard of radiography w very high; indeed, a high standard indispensable, if it is desired to tra the cause of such a fine and diffu fibrosis as that produced by asbe tos. The films are superficially, but on superficially, comparable to silicosi In the earliest negatives studied wii Dr. Tattersall, a characteristic slig; obscuration of the lung fields, a gener lack of translucency, was noted. Th appearance, for want of a better terr was denominated as "veiling." E Burton Wood has independently nott (19) and confirmed this, referring to as the "ground glass appearance Dr. Tattersall also drew attention ; the more or less rounded "whorls" < | BB 0007185 J CG 15I'M x i. Mar. li PULMONARY FIBROSIS IN ASBESTOS WORKERS 213 varying size seen in the striation in the mid-zones in some of the films. There was general agreement as to the fine and delicate nature of the characteristic mottling. Dr. Twining (in a personal communication dated Aug. 2, 1929)--while lamenting that there has been, as yet, neither time nor opportunity to study the changes from every aspect, and therefore his present views may be modified on considera tion of all the evidence--states: In general my opinion is that the earli est stages are not characteristic radio- logically, but that the stage of fine dusty stippling is almost certain to be eventually provable as an early asbestos lesion. We saw it constantly in a large series of films, and after a little experience it is quite easy to detect it. Some of the other cases showed a few grouped lesions, like rosettes or leopard markings, each component being about the e of a primary lobule. These are similar lesions sometimes seen in tuberculosis. [ the asbestos cases I regard them as being groups of primary lobules making up a lobule, the walls of which arc infiltrated. They certainly seem to correspond in size with the macroscopic lesions seen in the pathological specimen. , The advanced cases sbowheavy basal and mid-field mottlings, common in pneumono- coniosis, with a tendency to avoid the apices. On the whole the lesions are distinctly less dense than those of silicosis, and are less easy to group into well-defined stages, but 1 think we can recognise: 1. A very doubtful stage of increased linear striations. 2. Fairly definite fine dusty stippled appearance. -- 3. Coarser mottling with increased linear striations. 4. Gross lesions with pleural changes and displacements due to the pull of the fibros- ___ing lesions. The few tuberculous lesions we have come across have been easily distinguishable. The radiographic appearances in the earlier stages are most marked on the right side at the base or in the central zone. This corresponds with the clin ical findings. This preference for the right side has been noted also in silicosis, by the South African ob servers. The cases showing radiographic signs of a dust fibrosis have been classified in three broad groups. This grouping, although unscientific, is convenient practically, considering the main purpose of this investigation. Indeed more precise classification based on the particular radiographic changes noted might well be mislead ing at the present time. Much combined clinical, radiologic, and pathologic study is required into the whole subject of these fine types of dust fibrosis, .which have been noted in workers exposed not only to silicate dusts other than asbestos, but also to other inorganic dusts .containing no silica, before it will be possible *o classify the radiologic changes as has been done so successfully by the South African workers in respect to silicotic fibrosis. . The hypothesis that, because asbes tos dust produces a pulmonary fibrosis with consequent deviations from the normal in the lung skiagram, the de gree and potentialities of this fibrosis can be assessed by comparison of its radiologic picture with those of stand ard silicotic films, is untenable. At least two general types of pul monary fibrosis caused by inorganic dusts can be recognized. A third, representing the purely peribronchial variety of fibrosis, might be added; or it may be that all dust fibrosis will -be found to approximate more or less closely one or the other of these two o CO oy Njgi. ;-!Sp if wi i mas- iT; 25;=r:i =s$ Uls. *rP% -Z it IT . 5 x C -.i * llftf: -s -:*= t*-' Vol. 1J a.' Vo.5 - | B B 0007136 | U5.I95. NOTE: THIS DOCUMENT Dl! 214 THE JOURN, file: types. These types are (1) that pro On studying the development duced by combined silica dust, an asbestos fibrosis as displayed in a ser example of which is seen in asbestos of radiograms, and especially in the i fibrosis, and (2) that produced by free available taken a year or more befor silica dust, represented by silicotic fatal termination, one cannot h fibrosis. asking the question, "What is th, These two types, while resembling here-which could have this effect one another in clinical signs and symp The answer is that the damage to t toms, differ materially both in the lung is much greater than it appears nature of the lesion produced in the be when judged by the silicotic star lung, and in the character of the asso ard. Asbestos fibrosis is much me ciated radiographic picture. Thus, diffuse; it spins its fine web, as attempts to weigh, consciously or were, crisscross throughout the lui unconsciously, asbestos fibrosis, or any enveloping and eventually strangli dust fibrosis other than silicosis, by the ultimate lobular structure, rath means of the standard radiographic than depositing itself in numero changes found in silicosis, is unsound more or less isolated foci, os in silicos and is likely to lead to a misconception Thus, at any rate in the less advanc of the potentialities of the dust in ques stages, the radiologic picture of t. tion, lesions'does not impress the eye, unco Badham (8) gives an example of this scioualy viewing it from the staadpoi. source of error in reporting the unex of silicosis. . pectedly early death of a man affected The radiographic picture may she with a fine fibrosis caused by an ortho- soft and fairly coarse nodulation, but clase basalt containing no free silica. is neverso impressive as the nodulatic Referring to some of the radiologic in a silicotic film. differences between the fine fibrosis of Paradoxically, the distinctive fe. dusts other than silica and the nodular ture, both clinically and radiologicall fibrosis of quartz dust (t'.e., true sili of the asbestos fibrosis is its uniforroit; cosis), he states: The modesty of the symptoms; tt unobtrusive, but diffuse, impainnei Moreover, the coarse fibrosis of silica gave of the percussion note; the home clear interspaces of normal lung, while the fine fibrosis presented a uniform granular mottling leading to the conclusion which is probably erroneous that the actual develop ment of fibrous tissue was greater in a nodular fibrosis as silicosis than in a general ised fine fibrosis caused by silicates. To me it appears that the mechanical damage to the lung is greater in a fine fibrosis than in a coarse fibrosis when both are well developed. geneous stippling of the skiagram; a are fragments of an entity, unmistal able when assembled, but enigmat: when divorced. Only two references to the radic graphic appearances of the chest i asbestos workers have been traced one in a report by Pancoast an Pendergrass (10), and the other in a article by Burton Wood (19). The evidence obtained in the present Pancoast and Pendergrass togethe inquiry amply confirms this general with Miller and Landis examined "1 statement. asbestos workers, 2 of whom showe CC i.smk T~BB~0007'i37*T J. I.L My, ir. PULMONARY FIBROSIS IN ASBESTOS WORKERS 215 st stage changes and the other 15 definite second stage appearances, Of the men longest at work, one after seventeen years' occupation showed very definite diffuse, 'soft' spots throughout both lungs, and another showed about the same appearance after fourteen years' occupation. Very slight nodular shadows were found in one man after only two years' occupation. Most of these second stage cases showed also well-marked first stage appearances still present, indicating a persistence of free drainage hilumward. In all instances the nodular shadows were characteristically 'soft' and varied considerably in size." Their first stage appears to correspond with stage 1, and their second stage with stages 2 and 3 mentioned above, It appears from the context that these observers regard asbestos fibrosis as being really a silicosis due to admixture of free silica derived from the iginal rock--a view difficult to sub^^tanti&ie. Burton Wood (19) in a series of fif- teen skiagrams of asbestos workers notes: "The most noticeable feature of skiagrams of workers exposed longest to asbestos dust is the presence of shadows suggesting a diffuse fibrosis affecting chiefly the lower two-thirds of the lungs. The fine quality of the shadows is worthy of note. Some of the cases exhibit a 'ground glass' appearance, though on close inspection . fine mottling is evident. . . . when more definite mottling is present it lacks the coarse quality described in .. the skiagrams of chests showing pneumoconiosis, e.g. South African gold miners............... " _ _ Clearly, the maturation of asbestos .. fibrosis is spread over a period of years, and by the time the stage is reached when the features discussed above are, in varying degree, positive, and the radiologic picture is recognizable, the fibrosis is not in its inception, nor even in its earliest stages, but is developed and fairly widespread, We must, therefore, recognize an earlier state when the fibrosis is present in slight degree, and also when there is evidence of choking of the lymphatics, and of a measure of pulmonary catarrh, This stage may be referred to conveniently as the prefibrotic stage, The indications of this stage are indefinite, and some, at any rate, not specific. If, however, they can be determined and applied with only a moderate degree of accuracy, information of practical value will be available. Efforts have been made, therefore, to distinguish workers in this stage, The following tabulation shows that twenty-one workers out of 363 examined (5.8 per cent.) were so classified: Clinical Examination* . Per pfibrotic conditions......... 21 Radiologic Examinations (iss): Fibrosis................................. 52 Suggestive changes not brosia* * !.!!!__ " 22 5.8 39.1 16 5 Many of these cases present a slight diffuse impairment of percussion note --perhaps better described as a slightly increased sense of resistance felt on percussion, mostly of the right lung, at least as contrasted with the left, and associated with some weakening of the respiratory murmur. Probably this early stage could be detected radiographically, but only by means of Vol.U No. S it , Jr SftTij*;3* v V** *% m Uj Y if: ; *1: .5 `j. 5 v v* ?5 .R"***' " < !- i S* E5* h Si w.-Ji 4 -t -2 2 in ^ 8 T * j- 2 Y? g 5 a. a- = StL "tF;jjei iJr-iSa >x: m tag' GG I c: 117 NOTE: THIS DOCUMENT DIQ 216 the joTf*8&GMtmm pwm.Es comparison with a radiogram taken prior to commencing work with asbes tos. By such means the earliest stages of silicosis have been worked out by the South African observers. There, the radiograms taken at peri odic six-monthly medical examinations can always be compared with initial radiograms taken before the employees are permitted to work underground. group is dismissed from any furth consideration. A general summary of the findings the 374 workers wh were examin clinically, classified under the most ii portant lesion, is presented in Table Illustrative Casss The salient points of a few cases a set out below to illustrate clinical ar Due-to Asbestos Duo id Other Causes Duo to Asbestos | Duo to Other Causes W ith Evidence of a Dust Fibrosis | Other Active Lesions Other Lesions TABLE 4.--GENERAL SUMMARY OP FINDINGS CLASSIFIED UNDER THE MOST IMPORTANT LESION auN S0* tt mfht CASES PRE- or FIB ROTIC FIBROSIS CONDI TIONS FUUiONART TUBERCU LOSIS 1 ftj sas|m2 Pf 2zE Xuo 43 fftt ZM r a< . Xu o Z 3 Um o> i-a<a*3 o,- ao pog B 5 'ie.ts t*- oe 5fbt l<2Q0_fo-<tH-hS**g J1440 O *3 25 5 r 33 2* ft aj R z5 OTHER PULMONABT LESIONS xe 33 *< 52 2 oAt u * *fOct ^5 sO a. a w 0H9 2 3 4! fecXt 2; 5 0-4.................. 92 0 3 5 0 0 0 0 5-9.................. 142 36 1 12 0 1 1 4 10-14................. 89 27 5 3 0 3 0 3 15-19...,.......... 30 15 1 1 1 0 0 1 20 and over.... 21 17 0 0 0 1 0 0 13 3 5 0 0 7 1 0 1 62 3 5 2 2 72 0 3 2 0 33 2 110 7 1 010 1 Total............ 374 05 10 21 1 5 1 8 21 13 10 6 3 ISO Percentage... 100 25.4 2.7 5.6 0.3 1.3 0.3 2.1 5.6 3.5 2.7 1.6 0.8 48 1 One case of thickened pleura due to old gunshot wound. 1 One case of emphysema due to gassing. In other cases included in this group, diffuse weakening of the respiratory murmur was noted, with fine sticky riles in the root areas. At present no stress can be laid upon this group. The clinical changes are so slightly marked that until comparative radio grams are available it would be unsafe to draw any deductions. For the pur poses of this inquiry, therefore, this other features. Five radiograms art reproduced to illustrate the radiologit appearances of some of the cases There are insuperable difficulties however, in reproducing the fine: changes depicted in the original nega tives. Cahk 1.--Thin worker, a female, ngcd2t, lms been employed in asbestos 1or ten nmi onc-lialf yenrs- ns u cunl tenter oim year, J. I. H. / PULMONARY FIBROSIS IN ASBKSTOS WORK ICRS 217 nil as a doubler nine and one-half .years. Her family and personal medical history contain nothin); of note. She has no com plaints and feels quite well. Her nutrition is good. She is pale, hut shows no cyanosis. Cheat.--She has a chest expansion of 11 inches. No impairment of the percussion note is detected. The breath sounds m the right lung are weaker, generally, than those in the left. Expiration is prolonged at the right root; no added sounds are heard. A skiagram showed some very slight and doubtful changes in the direction of in creased striation. Case 2.--This man, aged 24, has been employed in asbestos for five years, carding and mixing. Previously he worked for four years in the cotton trade, yarn weighing. His family and personal medical history contain nothing of note. He has had a slight morning cough and expectoration for a year. His nutrition is good. His color is fresh, and there is no cyanosis. Cheat.--There is some impairment of the percussion note over the middle third of the right lung, behind, and slightly at the right The breath sounds arc harsh, and nation is prolonged in the upper half of right lung, behind; expiration is also 'prolonged over the left upper lobe, behind. The respiratory murmur is weakened at the right base, and the breath sounds arc of a "whiffing" character. There are no added sounds. A skiagram showed enlargement of the right root, and slight haziness and striation in the central zones in both lungs, suggesting early fibrosis. Case 3.--This man, aged 32, has been employed in asbestos for six years in the card room, and as a stripper and grinder. Previously he was employed in a cotton card room for nine years. He had army service for five years, but was not gassed. He gives a family history of asthma; otherwise there is nothing of note in his family or personal medical history. He has no complaints and feels quite well. His musculature is very good. His color is pale, but he shows no cyanosis. Chest.--There is slight impairment of the percussion note generally, particularly at "*the right base. "The"respiratory murmur is s little weakened generally. No added _ sounds are detected. A skiagram showed old tuberculosis of the lung roots and gen eral increased striation, especially in the lower half of the right lung, suggesting early fibrosis. Case 4.---This worker, a male, aged 23, has been employed in asbestos foe nine years, mostly mattress making. HU family and personal medical history contain noth ing of note. Ho complains of occasional pain in both sides of the chest, and perhaps a little undue shortness of breath on excr- ^- - rC?- Fig. 1.--Case 4: Moderate fibrosis. Un due degree of striation and fine mottling in central zones of both lungs; calcified glands in roots, with rather coarse striation in upper lobes; ? interlobar pleurisy on right side, between the lower and middle lobes; emphysema at bases. lion. Ills color is normal. His muscula ture and nutrition are good. Chest.--There is no retraction of the apexes, but there is a slight flattening below the right clavicle. The percussion note is slightly impaired generally, behind, partic ularly on the right side. The breath sounds are weak, generally, and expiration is pro longed. No added sounds are detected. The skiagram (Fig. 1) shows an undue degree of striation and fine mottling in the central zones of both lungs; calcified glands in the roots, with rather coarse striation in O o > iSf , ;l I* 'r"t"y SI W-tr "i : -*r: * : Star 9 * . v-- p ** , T *jpj -J*. = S *> tz-v z r> ,-r3*. n p- n -CiCTlS: 5 J * ! -3 --^ "I'm* ists ** ' ' A < ft u-ta, > >? "J != -- ; i II f' -Jv 1 3*' ;-.1 -.*wJT w \ t,` mss ' TfS-lS-j JH-.i&i <*&Si -- Vul, 12 | BB 0007190 J GG-15I99-- W3 im ! -7 \ MU&SH 'mM 'lg3Ef?i-vf?e ? J [ ';'r*Tv^.v r r1? ?-! < v: yj f. 1< }* fw * *sC f f . :' CT i - 'i J- 4* -1* Af. - '- r m<* **1 *7 *1 , J# r.-g-T^ ; - I: THIS COCl'y c;'T Olv 21S THE JOUENA [At -HYGIENE ^ the upper lobes; ? interlobar pleurisy on the right side, between the lower and middle lobes; and emphysema at the bases. The case was diagnosed as moderate fibrosis. Case 5.--This woman, aged 40, has been employed for eleven years in asbestos, for most of the period mattress making. Pre viously she was employed in a laundry. She has recently been ill for three months with pleurisy (no history of tapping); other wise her family and personal medical history moderate fibrosis, most marked toward t bases. Case 6.--This worker, a female, aged has been employed in asbestos for sev years, opening, and has been exposed much dust. Her previous employrae was non-dusty. Her family and persor history disclose nothing of note. She co plains of having had a cough for five yea and of shortness of breath on hurryii She is thin and undernourished, and pa til fils-- \i4*. - k '*,.< .. T-.-* S? r. aJ Spl'i-. >-;: 1: .3 S>'-s 1> y- Fig. 2.--Cose 6: Moderate, but fully developed, fibrosis. Enlarged glands in both roots; diffuse fine mottling in both lungs, especially the right. Fig. 3.--Case 7: General fibrosis, most linear, but with little mottling of right lun Old puerile tuberculous scars at apexes. are negative. She complains of having had a winter cough for three or four years, and of shortness of breath on exertion since her attack of pleurisy. Her nutrition is good; her weight is stationary. She has normal color, and no cyanosis. Cheat,--There is some general impairment of the percussion note over both lungs, be hind, more noticeable at the bases. The respiratory murmur is weakened generally. Persistent crepitations and medium rides arc noted low down in the right axilla. A skiagram showed diffuse fine striation and fine nodular mottling, with light opacity at the buses. The fuse uus diagnosed us Dust is present on her hair and in h nostrils. Chest.--She has a chest expansion of on fourth inch. There is slight general impai ment of the percussion note, definite at ft apexes and the bases. The breath soum are weak; expiration is slightly prolongeNo added sounds are heard. Her heart not enlarged, and no murmurs are detecte> The skiagram (Fig. 2) shows a number enlarged glands in both roots, and a diffu fine mottling in both lungs, especially tt right. This is a case of moderate, but ful' developed, fibrosis. Cask 7.- This woman, aged 4iS, bus bee | BB 0007191 i Cr i.^iV" * rj -1- --r \ A rv j--! nry-v iaftstaHs' TULMONARY FIBROSIS l.Y ASBESTOS WORKERS 219 \dIh,ployod in asbestos for thirty-two years-- employed for twenty years in asbestos in about three years on cards, and the re many capacities. There is nothing of note mainder as a spinner. Site lias done no in his family history, lie gives a history of other factory work. Jler family medical pneumonia a number of years ago. Ill's liistorj' discloses nothing of note. She has complaints are: a little shortness of breath a jiersonal history of nephritis seven or eight on exertion for the last two or three years; years ago, causing three months' illness. otherwise none. His nutrition is fair only. Her complaints arc: shortness of breath on His color is fresh, but there is slight cyano hills, and winter cough fur about six years. sis of the lips, at times. Her nutrition is fair. She is rather pale. C/iesb--The skin is poorly elastic; there Chest.--She has a chest expansion of ouc- is some retraction of the apexes. There is half inch. No retraction of the apexes is an impaired, rather "boxy," note on percus noted. There is general slight impairment sion, generally, especially over the upper of the percussion note, behind. Breath half of the left lung, and over the upper two- sounds are harsh and expiration is pro- thirds of the right lung, behind, and in - longed. No added sounds arc heard. No front. Respiratory murmur is generally gross enlargement of the heart is noted, but weak. Expiration is slightly prolonged, the second sound is found to be accentuated but diminishing toward the bases. Pleural over the aortic area. The skiagram (Fig. 3) crepitations are noted low down in the right shows a general fibrosis, mostly linear, but axilla. A skiagram showed a definite fine with a little mottling 'of the right lung. diffuse fibrosis. Neither lung lights up very There are also very old puerile tuberculous well, and throughout both there is a very scars at the apexes. The case was diag fine diffuse reticulation and mottling-- nosed as general fibrosis. moderate, but fully developed, fibrosis. This case should be compared with Case The fine diffuse character of the radiologic 6. In Case 6 there was a heavy exposure to appearances is particularly noticeable here. '-st extending over a few years; in the pres- Case 10.--This man, aged 40, has .been case there was exposure to a very much employed for twenty-five vdars in asbestos, s concentration of dus.t, except possibly the first three years, but extending over V^4ny years. Case S.--This worker, a male, aged G2, during nine years of which he was not ext posed to dust. Fof eleven years of the remainder he was employed in the card room, and mattress making. His family has been employed in asbestos for twenty and personal medical history disclose noth years as a weaver. He was previously a ing of note. Ilis complaints are: shortness cotton and silk weaver. Ilis family and of breath on exertion for three months; personal medical history show nothing of cough after a few hours' work in dust during note, except that he was regarded as a deli the last twi> or three years, with little or no cate child. Ills complaints arc: shortness expectoration; and pain in the left side of of breath on exertion, and on going upstairs, the chest for the last three months. His for three years; morning cough and a little nutrition is good. He is pale, with slight expectoration for the last three winters. duskiness of the lips. He is thin and pale, with some cyanosis. Chext.--There is some retraction of the Chest.--Chest expansion is l inch; there apexes. The [K-rcussion note generally is retraction of the apexes. The percussion is impaired, and of a "boxy" character. note is impaired over both upper lobes, in Breath sounds arc harsh and expiration is front, and over the upper two-thirds of the prolonged over the right upper lobe; else right lung, behind. Expiration is pro where the respiratory murmur is a little longed at the bases. Pleural rub and incon weakened and expiration is not materially stant riles are noted at the left base, and a prolonged. No added sounds are heard. few idles at the right base. A skiagram The heart is normal. The skiagram (Fig. showed a definite diffuse fibrosis with nodu- 4) shows diffuse striation and fine speckled iation. This is a case of fibrosis in the early mottling throughout both lungs--fibrosis,. ^advanced stage... .. fully developed. __ ... Case 9.--This man, aged 41, has been Case 11.--This worker, a male, aged 40, Vot. 11 .4 Sc^0','ppa THE JOURNAL SfWDl has been employed for twenty-two years in asbestos--during the first eleven years on cards and as a weaver, during which lie was exposed to a considerable concentration of dust. During the remainder of the time he was employed on a non-dusty process, but was exposed to a less concentration of dust derived from other processes. His family and personal medical history give nothing of note. His complaints are: shortness of breath on climbing stairs for the last five yearn; slight morning cough and expectora- Fig. 4.--Cose 10: Fully developed fibro sis. Diffuse striation and fine speckled mottling throughout both lungs. tion for about the same time; and slight aching of the chest in front, below the left clavicle. His nutrition is good. There is slight cyanosis of the face.___ Chest.--Chest expansion is 1 inch; there is retraction of the apexes. There is im pairment of the percussion note generally, most evident over the whole of the right lung, behind, and over the right upper lobe in front. The note is "boxy" over the remainder of the chest. The breath sounds are slightly weakened generally, except at the right apex, but there is no gross change. Expiration is prolonged generally. Vine crepitation* urn heard in both axillae, and over the right upper lobe, in front. T heart is normut. Sputum is mucoid, but negative for Bacillus tuberculosis. CIn bing of the fingers has been noted for abo two years. A skiagram showed an exte sivs diffuse fibrosis--fibrosis in a fair advanced stage. Cass 12.--This worker, a male, aged has been employed in asbestos for twent six years in the card room. Previously was a sawyer's laborer. There is nothh of note in his family and personal medic history. He complains of slight shortne of breath on exertion of recent years, ai of winter cough for the last three or fo years; expectoration is stated to be n His musculature and nutrition are fa. There is slight cyanosis of the face. Chest.--He has a chest expansion of thre fourths inch. The percussion note is ir paired generally, especially over the le upper lobe in front. The respiratory mu mur is weakened over the whole of the che except the left-upper lobe, where there a whistling breath sounds, and medium rale The heart is normal. A skiagram showe "very extensive changes throughout the che: of a coarse type without fine stippling. Tf roots showed a choked appearance. The: was heavy mottling at the base. One ol tuberculosis focus was noted at the left bas< and some calcified glnnds in the left hilun The diagnosis was fibrosis in the advance stage. Case 13.--This man, aged 66, has boei employed in asbestos for twenty-one year, os a weaver. For about sixteen years pre viously he was a cotton and silk weaver His father died of "chest trouble" at the agt of 45; his sister died aged 15 of pulmonar; tuberculosis. He has only been away sick ; week or two in twenty-one years, and ha never had any serious illness. His com plaints arerundue shortness of breath or exertion during the last two years; cougl for the last two or three winters. Expector ation is creamy, and occurs a fair amount o times. He has lost weight, and is thin. Hi is pale, but with some cyanosis of the face and with a malar flush. Chest.~*Chest expansion is li inches there is retraction of both apexes. Did nest is detected mi pcmi.-i.sinii over the upper two-thirds of the right lung and over thu left j. i. k .May, HOC | BB 0007193 \ kidirnTm^ PULMONARY FIBROSIS IN ASBESTOS WORKERS Ippcr lobe, behind, and over botii upper lobes in front. Breath sounds arc rather weak, with prolonged expiration. Scat tered variable rhonebi and Riles arc heard over the right lung, ltchind, over the left upper lobe in front, and over the left root. The skiagram showed a definite diiTu.se fibrosis plus tuberculosis. Sputum was negative (one examination). The diagnosis was dust fibrosis in the advanced stage, with tuberculosis, probably active. Case 14.--This worker, a mole, aged 30, commenced work in an asbestos plant in 1910, but was employed on other work until January, 1914. During the next five years, until early in 1919, about three years and nine months were spent in army serv ice, for nine months of which he was a pris oner of war, but he had two short periods of work in asbestos--eleven months in the weaving, and six months in the mattress, departments. From early in 1919 to No vember, 1927, he worked in asbestos proc esses, but for only six years and ten months in a dusty one (mattress making). He then ceased work, lie was referred to a tubercu losis dispensary on Oct. 19, 1927, when he "c a history of bronchitis in 1910 and 1917 ng the War, and of never being very well cc;`complaining of dyspnea, .pain in the right' side, and a slight cough of only about six months' duration, with a small amount of grayish sputum. Dr. N. Tattcrsall states that at that time: "Dyspnoea was very marked, even on talking, and there was definite cyanosis. He had marked hollowing and respiratory TetTaction at both apices, especially the right; loss of note over most of the right lung and the upper half of the left; bronchial breath sounds at both apices; fairly numer ous crepitations, most!)- on the right side, and a pleural rub at the right base. He had a systolic bruit at the apex and pleuro pericardial friction. "I examined him a number of times, the last occasion being April 20, 1928. In that time he had lost 9 pounds, felt very weak, and the dyspnoea was increasing. The signs remained much the same, though occa sionally, if he got a cold, the moist sounds were more numerous, especially at the ~"Tiafes?' Seven "sputum examinations were negative, and up to the time I last saw him the sputum had remained small in amount, and its ap|K*aruncc did not suggest tubercle, "My diagnosis from the beginning was one of pulmonary asbestosis with possibly added tubercle. "t took two X-rays of him, neither of which showed appearances suggestive of tubercle, everything pointing to a very extreme degree of fibrosis." He died on Oct. 13,1928. No postmortem examination was obtained. Fig. 5.--Case 14: Massive fibrosis, with pleural thickening, retracted apexes, anti pneumothorax on left side with incomplete collapse of lung. It will be noted that the length of expo sure to asbestos dust is unlikely to have been more than about ten years and two months, and of this time he was employed only about eight and one-half years in a dusty process. War service, of course, may have reduced his resistance. The skiagram (Fig. 5) shows a massive fibrosis with pleural thickening, retracted apexes, and pneumo thorax on the left side with incomplete col lapse of the lung. No doubt fibrosis of the type pro duced by asbestos dust can of itself lead to complete disablement, and VoL 12 Na.S ......................... _ . . 222 finally to a fatal termination, even in the absence of a superadded tubercu lous infection. The primary effect of the fibrosis would appear to be that of causing defective aeration of the blood, result ing in an added strain on the heart. For many years, and even with an advanced degree of fibrosis this may be of little inconvenience, provided physical exertion is limited, and acute illnesses are avoided. Ultima however, the margin of -..ifeTy, air diminished, is lost and circuL slowly fails, with the usual sign edema of the lungs. More o however, an attack of bronchop moniu, influenza, or other acute ir tion adds too much to the strain, pairs the cardiac musculature, results in a fatal termination. (To be conclu'lr-I) BOOK REVIEWS Bleivergiftuxg. By Prof. Dr. Paul Schmidt, Direktor ties Hycirniaehen In- ' - stituts der Universitiit Halle a. d. S,; Priv.-Doi. Dr. Adolf Seiner, Oberussi.itent am Hvgieniscnen Institut Halle a. d. S.; und Priv.-Doz. Dr. Slillfricd Litinrr, Assistant an der Medizinischen Klinik Halle a. d. S. Paper. Pp. 79 with index, illustrations, and blhlioeraphy. Berlin and Vienna: Urban & Schwarzenberg, 1930. This monograph is divided into a short introductory or general section and a special section. The first purt is devoted principally to a discussion of the outstanding diagnostic symp toms of lead poisoning and of the work done by Dr. Schmidt and his collabora tors in the microchemical determina tion of lead in blood, urine, and feces. The second part discusses in detail the usual sources of lead poisoning; the absorption, distribution, and excretion of lead; the pathology and clinical find ings associated with lead poisoning; and, finally, the diagnosis, prophylaxis, and therapeutic treatment of lead poi soning. Dr. Schmidt's monograph is particu larly apposite. It brings :be literal of the subject down to the present c and represents the mature? though an investigator who has long made field particularly his own. The dis sion of the diagnostic features of 1 poisoning is especially clear and to point. In this connection it is of tercst to note that emphasis is pla on the importance of the determi tion of lead in the blood. No attempt is made to discuss details of technic. The monogr. presents instead a critical review of more recent experimental work rei ing to lead poisoning and will, in c sequence, doubtless have a wide ; peal to all investigators in this fie The bibliography, which contains 2 references to the recent work a brings the literature of the subj> down to 1930, is particularly valuat "Bleivergiftung" may well be reco mended as a valuable addition to t library of students of public health L. T. Fairhall. 1 BB 0007195"] GG J* I. May, .