Document zbLK0z7Lb2YDyjVxREBNvnEd0

FILE NAME: Asbestos Mining (ASMI) DATE: 1950 Feb DOC#: ASMI018 DOCUMENT DESCRIPTION: Journal Article by Dr. Merewether - The Pneumokonioses Developments, Doubts, Difficulties / 0 ^2-- quire our school authorities, local provincial and Dominion governing bodies; to provide adequate clinics for the reception and treat ment of the deafened child, and monies to further the work so ably started by doctors in School authorities and local provincial and Dominion governing bodies will find it necessary to take greater interest and provide more facili ties for the examination and training of the hard-of-hearing child. the larger medical centres.4 It is the opinion of all otologists that the care of the deafened must be commenced early in life. It is also recognized that the doctors are anxious and willing to carry out the treat ment and re-establishment of those who have REFERENCES 1. F ish e r , a E . : E ye, E ar, Nose & Throat M onthly, 5; 9 9 0 1 Q4Q 2. M acfa rla n / d . : J. A. M. A ., 137: 774, 1948. 3. F e e , G. A .: N at. Soc. D eaf., 1948. 4. N e w h a r t , H . : Trans. Oph. < O t o M a rc h , 1943. 925 \V. Georgia St. serviceable hearing, but it is recognized that before any work can be done on a provincial 'or Dominion-wide scale, the Departments of Health and Education must provide buildings, THE PNEUMOKONIOSES: DEVELOPMENTS, DOUBTS, DIFFICULTIES* equipment and lay teachers, to re-habilitate those deafened children who require speech training, voice correction and re-habilitation in their lives. We know little has been done on E. R. A. Merewether H. M. Senior Medical Inspector of Factories, Great Britain, London, Eng. IT- any concerted large scale. It would therefore seem necessary that we, from the several provinces of this Dominion, should return . buoyant in the hope that work would commence as soon as possible on a program for the diag1 nosis, treatment and education of the hard of ' hearing child. This was stressed by the PresiU dent of the Canadian Otolaryngological Society in his address before that organization. PREVIOUSLY in the history of the pneumo- konioses there have been times when the path of progress has disappeared in a forest of data and the traveller was beset with doubts. It seems that we have reached just such a point now, when we must stop and take our bearings. Firstly, what really is the present position? In England we have some 800 deaths a year from pneumokoniosis and. there are over 16.^00 cases ; ,' Summary There are children born deaf and there are others who become deaf between birth and two ` : years of age. Ordinarily, these will not be able v to learn to speak. ' ' Heredity is responsible for only 25% of . deafness in children. Early diseases of child registered as " disabled persons' . These num bers may not appear striking compared with the 4,000 deaths a year of adults from road accidents and the 20,000 deaths from respiratory tuberculosis. But, when we stop to try to esti mate the relative risks of death from these causes in relation to the numbers of people exposed to them, then the risk from pneumo hood cause 75%. koniosis appears fantastically high. On this . " Early training of the hard of hearing child basis, the figure of 800 deaths a year from pneu . is necessary. mokoniosis would have to be multiplied by . Surgical removal of infected and hyper- an unknown but large factor to view this risk "y . trophied tonsils and adenoids, the patency of in correct perspective. It can be said with cer ' the Eustachian tube, is one of the first- 'urgical tainty, however, that a few months' exposure to : procedures in treatment. silica or asbestos dust in gross or, to use Leroy < ' . . Radium applicators in the fossa of Rosen Gardner's happy word, " insulting" concentra , > .mueller may be necessary. I .. "'Yir;!Children in elementary schools are group- y tested and if found with a hearing loss of more fu than, twenty decibels, are referred for further i attention. The audiometer is being used more - and more with greater satisfaction to the tions will inevitably cause death. However, when we go further and think, not of one small country, but of the world and consider the toll of life throughout the ages from these diseases from all the mining, quarrying, fabricating and construction work carried out, we may well : otologist. Bead before the Eightieth Annual Meeting of the ` Institutionalizing of children should be Canadian Medical Association, Section on Industrial i : avoided if possible. * Medicine, Saskatoon, June 15, 1949. , -x * "',v;-.. yi-w - ; -4. 1 tih. yV 170 Merewether: Pneumokonioses [ F-tbai9so1,"vof'> regard them as one of the major scourges of humanity. Again, when we think of the achievements of medicine in preventing and curing diseases like diphtheria, we cannot help but ask, -with some thing of shame, why the mortality from these dust diseases remains so high, seeing that in theory at any rate, they are wholly preventable. It must be confessed that understanding of the problem and of its urgency, by the professions, managements, workers, and the public generally, is inadequate and ill-diffused and we cannot hope for real advances until this is rectified. This comes about because the pneumokonioses have no spectacular impact on the community, like accidents or dramatic epidemic diseases which make news headlines : silently and insidi ously they creep, like old age, upon their victims distributed over many industries, who fade away with little but local disturbances. They are difficult to diagnose and often masquerade as other diseases. The medical teaching schools and textbooks pay little attention to them and nothing to the industrial processes which' cause them--without a knowledge of which, diagnosis is but guess work, and also, the terminology used is vague and confusing. What is needed is national and international team-work like that applied to the study of atomic energy and then a very large measure of control of these diseases would be assured. The first steps are to agree, internationally, on a standard terminology, standard criteria of diagnosis, standard x-ray technique, and standard type films, minimum standards of preventive measures, of compensa tion and rehabilitation procedures, strictly en forced by law : priorities of aspects for immedi ate research on the medical, engineering and other scientific aspects and, above, all, we need intensive national programs of education with the aid of the popular, professional, scientific, and trade papers. Instruction should be made compulsory in relevant degree and diploma courses, in technical institutes and trade schools, and for workers, managerial, and supervisory staffs engaged in work which involve risk of these diseases. , Let us look, very briefly, at some of these points. Consider first J;he confusing termi nology used with these diseases. So far, I have had to use the words " these diseases" with the equally vague alternative " pneumokoniosis" in this discussion, for this very reason. Pneu- mokoniosis means " dust and the lungs" a vague generality which indicates no particular entity and implies no pathology and no dis ability. To medical men it means, without further definition, merely " any respiratory condition which may be ascribed to dust" . Thus, it may include anything from an ab normal x-ray picture as seen in welders, or silver finishers, or iron-oxide workers, due to diffraction of the rays by minute particles of metal dust which causes no symptoms, no dis ease, and no disability, to gross fibrosis of the lungs with extreme shortness of breath, com pensatory emphysema; pneumothorax, bron- . chiectasis, and gross pleural, pericardial, and diaphragmatic adhesions, as in advanced asbestosis. It may include cancer of the lung due to radioactive dusts, beryllium granulo matosis, and all the curious affections asso ciated with workers handling grain, bagasse, mouldy cotton and hay. Clearly an expression which implies both trivialities and most serious diseases is of no practical use and is liable to mislead. Again, consider the expression " siderosis" . It was coined first I think, as a respectable name for " grinders' ro t"--which, at least, told us something--to describe an interstitial fibrosis of the lungs 4hen thought to be caused by fine metal particles: a quarter of a century later, some people used, it as a name for silicosis in haematite miners, and now, after another quarter of a century it is used to de scribe both the killing fibrosis of haematite miners and the harmless spotting of the lungs by fine metal particles, discernible only by radiography. , Then if, in desperation, we turn to the dictionaries, what do we find? Taking one at random, after stating the derivation, of pneumokoniosis to be from the Greek, meaning lung plus dust, it goes on: " A lung condition due to the inhalation of minute particles. It is attended by fibroid induration and pigmenta tion. See aluminosis, anthracosis, asbestosis, byssinosis, chalicosis, ptilosis, siderosis, silico sis, and tabacosis." As you will observe, some of these expressions are merely alterna tive appellations, some may not exist and a number are not necessarily attended by, and are certainly not associated with, fibroid _in duration of the lungs. But, let us not give u p : on turning to " ptilosis" we are told it is " a form of pneumokoniosis caused by inhaling the Me r ew eth er: P neumokonioses 171 Cmad- M.A - J I t?hLl350.vo1- 62 J t o t from ostrich feathers" . What this defini tion really means only the bird knows. I will ot weary you further except to remind you that compound names are used, as for instance, the diagnosis and cause much hardship and in justice. We need, therefore, medical, scientific, and industrial knowledge and so--team work of the best class. silico-anthracosis and I have seen several cases You will note that the points I have men with both silicosis and asbestosis to which, tioned--causative dusts and processes, clinical fortunately, as yet no special name has been findings and x-ray appearances--as the basis of applied. This is confusion worse confounded: diagnosis, are also the basis for progress. With n0 wonder we mislead and are misled and when out accurate diagnosis the harmfulness of a dust the experts collide in the fog, the courts of law and. the hazard of a particular process cannot flee to the dictionaries, and what a paradise for be assessed, and without these, appropriate pre our. friends the lawyers. We simple minded ventive measures cannot be devised. I cannot and, of necessity, practically disposed persons, stress too much the importance of accurate diag must really avoid being hypnotised by the nosis and this, it is vital to remember, involves H\ I- tphheeorsr,etaincidantisdyanudp tshhiascnkolemdenbcylattuhree. leIxticmoiggrhat nTohnis-mleedaidcsal toas thweellfuarsthmeredpicoailntcothnasitdewrahtiiloensa. l 'profitably be discussed and agreed inter- certain amount of mysticism is not alien to the 'nationally, as has already been done in defining art and science of medicine, the age of witch 1:^1, the meaning of the term " silicosis" . craft in the practice of industrial health is long since past. Apart from the fact that the patient I "--'wy. Jn some countries, the law has had to step in needs a reasoned prognosis which necessarily is * for its own urgent purposes and tell us what based on accurate diagnosis, managements can | re-mean; "for industrial health is dependent not cope with the responsibilities laid upon them r !;?fhot only or* doctors and nurses but also on by law without skilled medical aid, and con -engineers, chemists, physicists, and so on -and sequently may be quite knowledgeable in these is primarily a responsibility of governments of industrial managements, and so every- matters. ne concerned must understand exactly what is Now what do we know of the relative harm (gymeant' and required. Thus, in our own fulness of dusts ? Regrettably, not nearly enough. National Insurance (Industrial Injuries) Act, Nevertheless, we can make some useful generali find that " the expression `pneumokoniosis' zations. The first is, that all dusts whatever means fibrosis of the lungs due to' silica dust, their composition will cause functional damage, asbestos dust, or other dust, and includes the but only some kinds have been proved to be condition of the lungs known as dust reticula- capable of causing fibrosis of the lungs, that is, ^ tion".- This has its pitfalls especially in the use true pneumokoniosis. The latter are those dusts : ' 'of the word " dust reticulation" , and its containing silica in the free state as SI02 and limitations, in that it does not include such also out of the multitude of other mineral dusts, - 'i - v `conditions as " byssinosis" (which is dealt with only the small class of fibrous silicates known as | - \ separately); but in spite of this it includes the asbestos. These in their pure forms, ^for ex g great majority of- related killing and disabling ample as quartz or asbestos, unmixed with other j forms of pneumokoniosis, and thus is a practi- dust, and in the absence of infections particu larly tuberculosis, give rise to the classical forms 'eal step forward. of silicosis, a nodular fibrosis, and of an asbes .Now a word or two on diagnosis: diagnosis is tosis, a cobweb fibrosis, which are closely re difficult, which is one reason why both here and flected in the typical x-ray pictures. r!. oi:- m England special boards have been constituted Therefore, classical silicosis and classical to determine finally diagnosis and degree of dis asbestosis are relatively easy to diagnose, but ability. In every suspected case, for- accurate so often we find these classical types modified ... __ diagnosis we need to know all about the dust by the action or mere presence of other rela fe.^s^ ji.oejdusta concerned and the length of exposure tively inert dusts, to which the patient has b e e n them, the complete occupational history from exposed at some time or another. Infections and first starting any work, the clinical history and some of these other dusts accelerate the develop findings, and the radiological appearances, and ment of fibrosis and others are thought to in inadequate information on and faulty interpre- hibit it, but all tend to modify, often profoundly, y>- t&tion of any of these aspects can wholly -wreck 172 M er ew eth er : P n eu m o ko n io ses r Canad. M. A' .1 L Feb. 1950, vol,B2 the pathology and radiographieal appearance of the classical types. This is where we may run into great difficulties in diagnosis and prognosis and in the advice we give to managements. Ex cluding terminal broncho-pneumonias, tubercu losis is the most frequent infection. In a series of over 2,000 deaths from silicosis and a series of 232 deaths from asbestosis investigated by my department, 50 and 31% respectively were com plicated by tuberculosis. This susceptibility to tuberculosis is covered by our law, which com pensates the sufferer from silicosis or asbestosis whether or not the disease is accompanied by tuberculosis. Exposure to other dusts such as in nickel refining by the Mond process (which also causes cancer of the ethmoid), in the manu facture of chromates and bichromates, and arsenic, is associated with an increased inci dence of cancer of the lung, but none of these dusts also causes a true pneumokoniosis.. A point of considerable interest which comes to light from our records is the possible associa tion of asbestosis and cancer of the lungs. In the same series, 13.2% of cases of asbestosis were found on autopsy to have cancer of the lungs. This is in contrast to silicosis in which our figure is 1.32%. Little is really known of the mode of action of silica and asbestos dust and the wherefore of these variations, but they emphasize the need for most accurate data on the human cases which occur. There are ob vious reservations to the direct application of animal work to humans. Scientists have pro pounded both mechanical and chemical theories in explanation, but as E. J. King has shown by laboratory experiment the different rates of solubility of silica from different dusts do not parallel their fibrosis producing powers. Simi larly Leroy Gardner's mechanical theory as to the mode of action of asbestos dust does not wholly explain the production of asbestosis. Again, Andrew Meiklejohn and \Y. W. Jones, in a follow-up of pottery workers, exposed to alumina dust have been unable to find any slowing up of the disease in cases of silicosis, in spite of the promise of the laboratory experi ments on the inhibition of the solution of silica by alumina. It does not follow that these theories should be discarded, but rather that other factors, including them, play a part and, maybe, in respect of the added susceptibility to tuberculosis particularly, the production of an imbalance of the intracellular enzyme system is one. Most enigmatic of all is the dis ease described by Shaver and Riddell, and also the mode of production of the fibrosis associ ated with exposure to beryllium, both of which pose questions as to the role of fumes in the production of pneumokoniosis. However, as all this may be, we must, like St. Paul, throw out a few anchors in the storm and, from the practical point of view, free silica and asbestos are the inherently hazard ous dusts which must be dealt with, whether encountered singly or mixed with other dusts. Although so-called individual " susceptibility", that is, the particular state of the individual's lungs plays a definite part, naturally, the greater the amount of silica or asbestos in haled, the greater the damage to the lungs. But, an important point is that they may be present in quite low proportions in -a mixture of dusts and yet cause much damage. Thus I have seen death from silicosis from exposure to an inert dust containing only 10% of added free silica and some samples of French chalk containing less than 10% of free silica and some asbestos, can cause both silicosis and asbestosis at the same time, although the pure material is inert. The reason for this is not difficult to see. A certain amount of silica or asbestos must be retained in the lungs to cause disabling disease, and the effect of overloading the lungs at the same time with large amounts of inert dust is to disorganize the normal lymphatic drainage, and so ensure the reten tion of the dangerous dust. This may well be the mode of production of the coal miner's lung, the result of exposure to massive concentrations of coal dust containing very little free silica. With exposure to con centrations of dust of this order, local blockage of lymphatics caused by overloading with dust, or by infections, will prevent the clearing of adjacent choked lobules and give time for the silica, a tissue poison, to act. Thus, we get a condition of focal atelectasis with focal fibrosis and compensatory focal emphysema through out the lungs, as is beautifully shown by Gough of Cardiff University in his whole lung sec tions, and this is a clearly progressive condition with continued heavy exposure. ^ So far I have touched generally on the prob lems of the true pneumokonioses, dusts in their etiological aspects and the pathological features of these diseases, and have stressed the vital importance to progress of pooling the skill of medical men, scientists, engineers, and manage ments I have referred to the many variations Vancouver, B.C. from the classical types of these diseases and A N analysis of the last 45 cases of mononucle the consequential difficulties in diagnosis and osis seen on the medical service of the Van prognosis and in assessment of the hazard of couver General Hospital has convinced us that the causative work. I have indicated that the it is timely to take stock of present knowledge doctor's approach to problems in this field is of the condition. three-pointed by way of occupational history, * Infectious mononucleosis is a self-limited dis clinical findings, and racliographical appear ease occurring in young people and characterized ances. Now, a few words on the third point-- by fever, sore throat, a swelling of the cervical the radiographical appearances. This is just lymph nodes and frequently of other lymph na much a headache as the other two, but is nodes, an increase in the mononuclear leukocytes vitally important and may be conclusive.^ The and a granulopeenia, and a positive Paul Bunnell pathological basis of the disease, that is the test. Of these symptoms and findings three are fibrosis, is of course reflected in the x-ray of chief diagnostic importance: (1) Cervical picture, but the classical appearances are more lvmphadenopathy. (2) Increase in the mono often than not modified by coincident tuber nuclear leukocytes. (3) A positive Paul Bun culosis, or by other disease, or obscured by the .highly diffracting effect of retained inert dust. -'-.Moreover, different radiographical techniques ; and different types of films can mislead com - pletely. Pending internationally agreed tech niques and type films which are long overdue, . the only practical suggestion, is to collect your own library of type films from cases whose nell test. Unless a patient exhibits at least two of these three findings, it is difficult to see how the diagnosis can be more than pure speculation.^ All the eases in our series have at least two of three criteria, and most of them have all three. An analysis is as follows: complete occupational and clinical histories .with autopsy findings are available. This can Total cases, 45. ,, Cases with cervical lymphadenopathy, db. Cases with marked increase' in mononuclear leuco- best be achieved by local medical societies. - In discussing this tremendous national prob lem of the control of pneumokoniosis, I may have given a pessimistic outlook in saying too much"about the difficulties of the position, but history teaches us that always just prior to great ", advances in knowledge and its application, v>e . ' have wallowed in just such confusion. Can we hope for a dramatic discovery to guide us, such as that of the bacillus of tuberculosis which A lases with positive Paul Bunnell test, 36. Of the 9 cases in which cervical adenopathy was not recorded, 5 had a marked tonsillitis. The one case which did not have a marked increase in the mononuclear leukocytes had 33% mononuclear forms in a total of 4,650, with 35% of polymorphonuclears and 28% staff cells. This patient had enlarged cervical glands, and the Paul Bunnell test was positive in dilu tion 1:320. He, therefore, showed the main ended one long period of confusion as to the features of the disease. . ' nature of these diseases, or that of the roentgen rays which pointed so imperiously the route to / better diagnosis'? Is it too much to hope that lines of research at present being pursued will ->- lead to a discovery of equal magnitude on the -./ preventive side, such as a perfect inhibitor or - _ a n .instantaneous continuously recording dust counter, or, dream of dreams, a dust arrester /which could be worn on the c h e s t or like a J;-:. miner's head lamp or both, and prevent dust A : reaching the mouth and nose and yet leave the Before proceeding with an analysis of the cases it is appropriate to discuss the Paul Bunnell test or hetero phUe agglutination. The serum of normal subjects con tains ang agglutinin (Forssman) i or sheep s d bio cells .which does not exceed a litrei of 1.8. In most cases nf infectious mononucleosis, after 7 to iu aays, uw serum shows an increase in this sheep's red cell ag glutinin and the litre may rise to very high figares (ui this series to 1:10240). Several examinations at inter vals of a few days, may be necessary to doteTM " the result is positive. It is generally agreed that a rise to 1-32 or more is definitely abnormal. A rise m utre has been observed in individuals who have recen tly re ceived injections of horse serum, but it is rare in othe conditions apart from infectious mononucleosis. It is k'cW* .'face completely free from encumbrance? I * Resident, Department of Medicine, The Vancouver General Hospital, 1948-49. hope so. -! i'i v :-r\ - '- > ' i / 'A : ? . A' \ - -r - v; A