The Significance of Lung Function Changes in Asbestosis

Asbestos isthenamegivento a series of minerals composedof fibroussilicates of magnesium andironwhichfindwidespread usein industry. Inhalation of thedustmay cause asbestosis, acrippling formofpulmonary fibrosis, whichusually doesnotappearuntil manyyears aftertheinitial exposure. Thereisalsoan increased incidence ofcarcinoma ofthelungin patients withasbestosis, andDoll(1955) estimated thattheriskoflungcancerinasbestos workers wasapproximately 10timesgreater thaninthe general population. Thediagnosis ofasbestosis atpresent depends onthehistory ofexposure tothedusttogether withcertain physical signsand radiological changes. Themostcharacteristic features ofthe latter areaground-glass mottling ofthelower zonesofthelungfields witha shaggy border to theheart. Thephysical signs areclubbing ofthe fingers andfinemetallic crepitations onauscultation ofthelungbases. Unfortunately manycases evenwithdefinite physical signs donotshowthe characteristic radiological changes, andtheearly diagnosis ofthedisease may bemostdifficult. The presence of 'asbestosis bodies inthe sputumsimply provesthatasbestos dusthas beeninhaled anddoesnotnecessarily imply that fibrosis ispresent. Thepurpose ofthepresent workwastorelate thechanges inlungfunction inasbestosis tothe clinical andradiological signs ofthedisease and totryanddetermine thevalue oflungfunction tests inassisting withitsearly diagnosis. PREviousLUNG FUNCTIONSTUDIES