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yjf' 7 yuj ftft/ft t INTERNAL CORRESPONDENCE HtLCEiVtD UG 1 '< 1983 UNION CARBIDE CORPORATION old rogebury ROAD, DANJBURf^tBf^JCI^ffP^, to o^mar. VDcm&or' Afo Copy to Medical Directors Contract Physicians oat* o^o.-wt-TO Dot* Ana Subc-, August- 8/ 1983 Corporate Medical/HS&EA Danbury > P2594 Asbestos Related Diseases Because asbestos related diseases both with and without asbestosis are a cause of considerable concern and confusion, I have attached an execellent article written by D. Davies that appeared in the July 16, 1983 issue of the BRITISH MEDICAL, JOURNAL. Davies has distilled a great deal of information into a succinct description of when compensability may be indicated. His comments on lung cancer are especially interesting. The fact that only a small percentage of pleural plagues (15% reported by Hourihane) are detectable during a lifetime by usual chest radiographs gives one concern. If our chest x-ray examin ations are of poor quality and are poorly interpreted, we could be accused of exercising inadequate "reasonable" care in our detection efforts. Hilton has been working with you to try to up grade our chest x-ray examinations and interpretations. I appreciate that Dr. Hilton Lewinsohn called this article to my attention. Hilton is our resident expert on asbestosis and asbestos related diseases so if you have any questions or problems give him a call on extension 8-421-5214. Thomas A. Kncoln, M.D. Corporate Medical Director TAL:cms enclosure UCC 008226 ,,164 value and importance ? Once the questions art identified it may be easier to choose the forum in which to answer them. Deputy Editor, BMJ Tony Smith 1 Anocyxnou*. Does Britain need an academy of medidne ? Bt Med J 1979 pi: 1611. * Godbcr G. An mniruic of health ? The Tima Health Supplement 1982 Feb 19:9 (col 1H). * British Medical Association. The medical effects of nudtor vtetr. The report of the British Mtdical Aiioaaiion'i Board of Science and Education Chichester: John Wile) and Sons, 2983. -Zzr Asbestos related diseases without asbestosis Asbestosis and mesothelioma are prescribed diseases under the Industrial Injuries Scheme and entitle the patient or bis dependants to compensation. The term asbestosis should be used only to denote fibrosis within the lungs. The three other non-malignant conditions associated with exposure to asbestos are pleural plaque, pleural effusion, and diffuse pleural thickening. The Industrial Injuries Council now recommends that, when it reaches a certain extent, the last of these should also be prescribed.' Pleural plaques develop in the parietal pleura, seldom cause disability, and are not to be prescribed. Pleural effusions may be transient but some are chronic and may recur* No pre scription is proposed for these, bui, under the new proposals, if they cause sufficient bilateral thickening of the pleura an application to a pneumoconiosis medical panel would lead to certification. Diffuse pleural thickening associated with exposure to asbestos has become increasingly recognised.* * Both pleura] layers are affected and restrict the expansion of the lung. Histological examination shows only non-specific fibrosis, and, as with effusions, the diagnosis depends on excluding other causes such as tuberculosis and other infections, collagen diseases, trauma, chronic uraemia, and drug induced fibrosis.5 With such exclusions, the Industrial Injuries Council is satisfied that bilateral diffuse pleural thickening in asbestos workers is likely to be industrial and recommends that dis ablement benefit should be awarded when the thickening is bilateral, is over 5 mm thick, and extends over more than quarter of the chest wall. ' The prescription of this condition will be welcomed, though some may be dissatisfied that the disease has to be so extensive to allow certification. Nevertheless, the committee suggests that this requirement should be reviewed in the light of experience. Tbe report also considers cancer of the lung in asbestos workers. At present this condition is not prescribed, but when it occurs in association with asbestosis it is considered to be a sequel and benefit is payable. Claims which have been rejected during life may be successful after death because necropsy may disclose previously undiagnosable mild asbestosis. The council now recommends prescription of lung cancer in patients with asbestosis and in certain other circumstances. In doing so it had to consider how to take account of smoking habits and the amount of exposure which would justify ryn-ifipanVin The- problem of the contribution of smoking to(lung cancqlih asbestos workers has been disposed of neatly. Studies in the United States in insulation workers have shown that the relative risks of developing lung cancer are: nan-exposed non-smokers 1; asbestos exposed non-smokers 5; non-exposed smokers 11; asbestos exposed smokers 53.* Because exposures increases the risk by a factor of five in both smokers and \ non-smokers the council recommends that smoking should be I disregarded. Cancer of the lung in asbestos workers may be divided into two broad types. Firstly, peripheral adenocarcinoma, which is unrelated to smoking and accepted as being due to asbestos exposure. The second is squamous, undifferentiated, and small-cell cancer arising in proximal airways, certainly related to smoking but only doubtfully related to asbestos. Perhaps wisely, tbe council makes no attempt to distinguish between these and recommends prescription irrespective of type. Most authorities accept that the risk of lung cancer is increased only when there has been heavy exposure to dust. Reasonable estimates of exposure may be made for people working in circumscribed places such as asbestos factories, but this may be impossible for, say, shipyard workers or engineers with intermittent exposure in various jobs, particularly in the distant past. Faced by this difficulty the council has made an ingenious proposal that the presence of other indicators of asbestos exposure should justify certification. It recommends prescrip tion when primary cancer of the lung is accompanied by one or more of the following features: asbestosis, bilateral diffuse pleural thickening, and bilateral pleural plaques. Asbestosis provides clear evidence of heavy exposure, but, though bilateral diffuse pleural thickening and bilateral pleural plaques are linked with exposure to asbestos, the relation is less definite and more capricious.' Moreover, pleural disease and asbestosis! are also pooriy'cbrrelated, for the former may appear in lig itly exposed people such as the wives of asbestos workers a id residents in the vicinity of asbestos mines and factories. Given a minimum exposure to dust, the development of pkt the diagnosis of plaques, is probably gc, usually taking over 20 years from the first exposure * * liy some 15% of plaques are detectable during life,' but this proportion might be higher ifoblique x ray views were used in addition to thtf routine ones." Hence probably the people who are certified during life will not be all those who have plaques but only the minority in whom they are demonstrable. The case for necropsies in people who have had industrial exposure to asbestos and die of lung cancer is dear. The council's aim has been to identify people " exposure to dust to justify certification if they develop lung cancer. Workable regulations are difficult to devise, nut the proposals favour those with pleural x ray shadows which may \ be the result of light exposure in the distant past and dis- \ criminate against those with much heavier exposure who, for 1 unknown reasons, do not develop pleural lesions or have not \ had time to do so. The council has decided against specifying a i duration and degree of exposure as qualifying condition because it considers this to be arbitrary and lacking in scientific validity. Even so, the criteria of pleura! lesions that it proposes are probably a less than satisfactory index and, though the extension of prescription will be welcomed--even if it requires legislation--probably many will find that the details of the proposals which are now before the Secretary of State for Health are unsatisfactory. D Davies Consultant Chest Physician, City Hospital, Nottingham NG5 1PB UCC 008227 MEDICAL journal volume 287 16 JULY 1963 1 Industrial Injuries Advisory CoundL Atbtnct-related duttui anlhonl asbestosis. London: MM SO, J982 (Cmnd 8750.) 1 Gaeniler EA, Kiplu AI Asbestos pleural effusion. Arm Intern Med 1*71 ;74.178-91. * Sheers C. Asbestos-associated disease in cmployeei of Devonport dock yard. Arm NY Acad Set 1979;330:281-7. 4 HUlcrdal G- Non-malignant asbestos pleural disease. Thorax 1981*6.' 669-75. * Albclda SM, Epstein DM, Gefter WB, MiBer SCT. Pleural thickening: in significance and relationthip to asbestos duti exposure. Am Rev Reiptr Du 1982;128:621-4. * Hammond EC, Sdikoff IL. Sddman H. Albeitot exposure, cigarette smoking and death rates. Arm NY Acad Set 1979;230:473-90. T Gibbs GW Etiology of pleural calcification; a study of Quebec cbryaotile asbestos miners and millers. Arch Environ Health 1979;34:76-82. * Rossiter CE, Bristol LJ, Cartier PH, et al. Radiographic changes in chryso- tile asbestos mine and mill workers in Quebec. Arch Environ Health 1972 *4.588-400. * Jones JSP, Sheers G. Pleural plaques. In: Bogoraki P, Timbrel! V, Gilson JC, Wsgner JC, eds. Biological effects of asbestos. Lyon: 1ARC, 1973. (1ARC Soentific Publication No 8.) 11 Hourihsnc DO'B, Lesaof L, Richardson PC. Hyaline and caldfied pleural plaques as an index of exposure to asbestos A study of radiologies] and pathological features of 100 cases with a consideration of epidemiology. Br Med J 1966 p: 1069-74. 11 Fletcher DE, Edge JR. The early radiological changes in pulmonary and pleura] asbestoiit. Clin Radiol 1970*1 355-65. Difficulties with knees Only a few years ago internal derangement of the knee wps an accepted diagnosis which led to arthroromy on the gainful side of the joint with, almost inevitably, the excisigB of the cartilage: "better to remove a normal meniscus thajr miss die tom posterior horn." Those days have passed; theAeniscus is now preserved at all costs, and in some centres it/nay even be repaired. One of the main reasons for this Aasge is that successive reviews of the late results of memsceaomy have shown that the operation is far from being twbign--and that it is certainly not the cure for all problems oftire knees. Meniscec tomy may, indeed, increase the problem/is a knee which is unstable from damage to the ligamentsj For the knee still remains an enigmaJaespite a wealth of new tests and diagnostic aids such as arthirocopy and arthrography. Among the most taxing of the promems within the knee are those of rupture of the cruciate lig/nents. Rupture of the pos terior cruciate ligament is the easrfr to manage. On examination the tibia is found to hang backAhen the knee is flexed to 90 with the foot on the examinatiA cpuch. The anterior draw sign is positive--the tibia can Ue drawn forward when the leg is in the position describedf-but in reality it is moved to the "normal" position onlvAelative to the femoral condyles. Radiographs may show an avulsed fragment from the posterior aspea of the tibia, 'treatment is conservative or operative. The fragment may be screwed back into position, or the liga ment may be repairA directly or replaced by nearby tendons or muscles. This irifury is frequently associated with major disruptions of the knee in which serious neurovascular injuries may occur rcg/irmg urgent attention. Longstanding injuries require earth/ assessment before surgery, which should aim at controlling Ay straight or rotatory instability. The exact nature of the suxAry will depend on the instability and is likely to be complicated. Surgery may not be needed, howeverj where pos sible tlr management should consist of quadriceps and hamstrinjfexerdscs to control the knee, with advice to die patient to c/auce his demands on the joint. Dandy and Pusey1 found in a group of 20 patients treated by this conservative pproach the functional results bore no relation to the degree of 165 laxity of the ligament--and 18 of the patients eventually decided that their symptoms wnowt severe enough to justify surgical reconstruction. The greater problem is i rior cruciate. After years of discussion authorities still, not agree. This difference of opinion was highlighted; in theJourno} of Bone andJoin! Surgery in February year. Hughston and Barren reported that rupture i the anterior cruciate did not in itself contribute to instabiO of the knee.* They believe that the instability which i in knees with this lesion is related to damage to the cap othcT ligaments and muscles, and the medialI meniscus,. Jh their bands careful evaluation and repair of the damagedSi tructures produced knees stable enough to withstand vigorous sport, whether or not the anterior cruciate was rupturedJ y emphasised the prime importance of the medial m< as a stabilising structure. By con Noyes et ai described the disabilit/ in 103 patients chronic laxity of the anterior cruriasp ligament uncomjdfcated by other major deficiencies or pra/ous recon struct* procedures* They showed that damaro to this ligamenywas detected in only seven of the 103 n/ients initially, inching those examined by orthopaedic surapons. They found if untreated an isolated anterior crudatp lesion would lead Ktialiy to a lower sporting achievement Ad later to reinjury, ge to the meniscus, and eventuallAo osteoarthrosis. The average orthopaedic surgeon fi/ds such a wide diver gence of opinion difficult to underctarifl. He should have found comfort in the sensible editorial in ti/ same journal, though the author, Robert Larson, could nor reconcile the differences* He did, however, anerupt to ghysome guidelines on manage ment based on his beliefthat alVthc structures play a pan in the stability of the joint; none is sf! important, all depend on each other. Thus to rt-establishpstabihty all damaged structures should be identified, repaired, or augmented. Larson argues that repair should be uAcrtaken urgently after injury, but acknowledges that thiApproach requires accurate and earlyy diagnosis. The anterkp cruciate itself, he believes, should no be repaired but ausnented, for experience bas shown tint repair is difficult a/d produces poor results. He thinfa/hat repair of the kneArith chronic injuries should be appaSached with caution, icf judicious advice to the patient naf obviate surgery, espedpiy if he is taught to develop hisJ&mstrings and quadriccA and Sower his athletic requirements. In those patieDts whrife knees are so unstable as to interfere with normal life--or throe who want to engage is sporting lAvities at a high standardAthe joint should be carefully Asessed and the appropriate repairs and augmentation unOTtaken. In tie light of all this conflicting evide/ce, what is the key ? PcrhAs the answer is a superspedahR service for the few va&nts who are crippled by the d/nage to their knee, or ips a better diagnostic serviq/for the acutely damaged knee, or perhaps both. C D R Ljchtowler Consultant Orthopaedic Surgeon,j Eim Nuffield Hospital, Brentwood CM15 SEH * Dandy DJ, Pusey RJ. posterior cruciate" loot-term results of unrepaired ton of the J BeneJoins Sstrg 1982 *4B V2-4. > Hughstm JC, GR. Acute anteromedial rotatory instabilicy. Long-term of surgical repair. J Bene John Smg 1983*SA:145- 53. * Noyei FR, Mriu EA, Matthews DS, Butler DL- The symptomatic anterior en/ate-dedem knee. Fan I: the iong-uxm functional disability^ athletically active individuals. J Bone Joint Snrg 1983; 86A:13_ . The knee--the physiological jam. J Bone Joint Snrg 1983; 5AH43-4. UCC 008228