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Conferences

TUBERCULOSIS

AN International Symposium on Tuberculosis, spon-sored by the Deborah Sanatorium and Hospital, was heldin Philadelphia on Nov. 20-22. It took the form of aseries of panel discussions. The individual panels wereconstituted from the following invited members:

Drs. Oscar Auerbach, Theodore L. Badger, Katharine R.Boucot, J. Maxwell Chamberlain, Paul T. Chapman, Aaron D.Chaves, David A. Cooper, Louis Reis Davidson, RobertsDavies, Nicholas D. D’Esopo, Israel George Epstein, Floyd M.Feldmann, Seymour Froman, Michael L. Furcolow, JuliaM. Jones, Edith M. Lincoln, Walsh McDermott, GardnerMiddlebrook, Carl Muschenheim, James E. Perkins, SidneyRaffel, James W. Raleigh, Edward H. Robitzek, L. H. Schmidt,George N. J. Sommer, Jr., John D. Steele, William Steenken,Jr., William B. Tucker, William M. Tuttle, Julius LaneWilson, and Guy P. Youmans (U.S.A.); Drs. Hugh E. Burkeand Frederick G. Kergin (Canada); Dr. Georges Canetti

(France); Prof. Carl Semb (Norway); Dr. Johannes Holm(World Health Organisation); Drs. J. R. Bignall and PhilipD’Arcy Hart, Mr. F. Ronald Edwards, and Prof. J. M. Robson(Great Britain).

Chemotherapeutic Prophylactic MeasuresThe necessary distinction was drawn between methods

designed to prevent multiplication of the infecting bacilli(" primary prophylaxis ") and those aimed at preventingclinical and radiographic manifestations from appearing(" secondary prophylaxis "). The discussion centred onthe use of isoniazid alone, and dealt with the results oflaboratory experiments with small animals and monkeystogether with the few planned studies so far carried outin man. There appeared to be almost general agreementthat in certain " high-risk " groups with known recentexposure to tuberculous infection, administration ofisoniazid was desirable for a few months-the probableincubation period of the disease-followed by vaccinationwith B.c.G. The possibility of using a vaccine fromattenuated isoniazid-resistant strains was discussed.

In the more difficult question of treating infectedindividuals once tuberculin skin sensitivity had developedwithout other manifestations, the possibility of impedingthe development of immunity by too early treatmentwas considered. In general, it appeared to be thoughtthat immunity had probably reached its full developmentonce tuberculin skin sensitivity had appeared and thattreatment with isoniazid at that stage would not necessarilyabolish it. A reasonable approach seemed to be to treatthose, especially infants and adolescent children, who wereknown to have recently acquired skin sensitivity; thisshould not be a general rule, but each case should beconsidered individually with regard to such factors as

environment and likely cooperation. There was some-

thing to be said for not extending such treatment beyondthese groups until the results of further studies were

known-those, for instance, being carried out by W.H.O.on tuberculin-positive individuals of all age-groups. Theredid, however, appear to be a case for paying attention tothe size of the skin reaction, as it had been clearly demon-strated that morbidity was higher in those found on firsttesting to have large reactions than in those with smallones. It could not be denied that resistant strains ofbacilli might subsequently emerge in a few people treated"

prophylactively " in this way, but there were good

a-priori reasons for thinking that this would be a very rare

happening, because of the small, sluggishly dividingbacterial population in such cases.

Chemotherapy of Manifest Disease andHospital and Home Care

For patients without symptoms or signs of " active "

disease there was uncertainty about whether drug treat-ment should be given in all cases. It seemed better tomake the decision in the light of the individual circum-stances of the case. Combinations of drugs were generallyconsidered desirable; but a case was put forward for usingisoniazid alone, at least in those with minimal or moder-ately advanced disease (N.T.A. definitions), and afterthe sputum had become negative and cavities closed.Further studies of this, now in progress, should give much-needed facts. Despite its disadvantages (concerning themagnitude of which there appear to be considerable differ-ences of opinion) p-aminosalicylic acid remained a

necessary drug, particularly in combination with isoniazidfor oral administration. There was no " universallyapplicable " combination, and the drugs should bechosen with regard to sensitivity of organisms, type oflesions, form of treatment planned, and the personalityand environment of the patient. High dosage of isoniazidseemed to be required for only a small proportion ofcases. It was agreed that all the drugs should be givendaily for initial treatment, and not intermittently. Treat=ment should continue for at least a year, subsequenttreatment depending on the initial type and extent ofdisease. The optimal duration in any defined set ofcircumstances had not, however, been so far determined.Corticosteroids were probably valuable for some severelyill patients, but further controlled studies were requiredbefore they could be recommended in less severe cases.There was wide divergence of opinion about the best

combinations of the " secondary " drugs to be used inpatients with cultures resistant to all three of the com-monly used ones-reflecting the paucity of facts on thissubject. There appeared to have been a general move-ment of opinion towards greater elective use of hometreatment. The effectiveness of treatment out of hospitalseemed to depend largely on the cooperation of the

patient and the skill of the physician, rather than on theparticular combinations and dosages of drugs. An impor-tant factor, at present little considered, was the regularitywith which the patients took their drugs. All aspects ofthis should be more fully investigated. There also

appeared to have been a well-marked change of opinionabout the necessity for bed rest; and it was agreed thatrest now played little part in the successful treatment ofmany patients.

RelapseThere was some difficulty in defining what should be

called a " relapse ". The panel could not be drawn intogiving figures for the proportion of patients under treat-ment who excrete resistant organisms after becomingtemporarily sputum-negative, and they seemed reluctantto call this a

" relapse ". Some considered that the

rediscovery of tubercle bacilli in the sputum was a

necessary criterion for purposes of study, but this wasclearly not essential in clinical practice. There wassome disagreement whether the bacilli recovered in

relapses after chemotherapy had been discontinued weremore commonly drug-sensitive or drug-resistant.The effect of host factors on bacterial persistence and

relapse was discussed. Experimentally it had not so farbeen possible by corticosteroids or other means to

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produce relapse in animals with latent infection broughtabout by treatment with pyrazinamide and isoniazid. Noevidence (as opposed to opinions) was forthcoming ofthe value of resecting tuberculous lesions compared withprolonged drug treatment in preventing relapse. Exo-

genous reinfection could theoretically occur after success-ful treatment of tuberculous patients; but no facts couldbe given about its actual occurrence. Infections by" atypical " mycobacteria (" para-tubercle bacilli ") werediscussed, and it was emphasised that laboratories shouldbe more aware of the possibility, frequency, and impor-tance of such infections, as awareness and skill are requiredin detecting them.

Case-findingDeath and notification rates in the U.S.A. indicate

that the control of tuberculosis has by no means beenaccomplished even in the economically highly developedareas. The high yield of cases from routine chest radio-graphy of patients admitted to general hospitals wasemphasised. But schemes of this nature must be accom-panied by an efficient machinery for dealing with the casesof tuberculosis so discovered and tracing the contacts.The dangers of radiation from chest X-rays appeared tohave been over-emphasised, particularly in the U.S.A.and Great Britain. The possible dangers called for

regular, efficient monitoring of X-ray techniques ratherthan reduction in the use of radiography as a case-findingmethod. Miniature photo-fluorography can probably bemade as safe as the taking of large films. Mass radio-

graphy should in general be used in high-prevalencepopulations rather than in attempts at total-communityor repeated surveys of known low-prevalence groups.Tuberculin case-finding programmes were considered.

It was re-emphasised that the follow-up of those withlarge reactions might be useful in detecting early clinicaland radiographic evidence of disease. Routine testing ofinfants and children in paediatric clinics could also bevaluable. There was a clear need for more simple tuber-culin tests to be developed. The depot tuberculin test,recently investigated in the United Kingdom, was

described, and it was suggested that it might eventuallybe useful as a " marker " for indicating that naturalinfection had occurred, hence reducing the need for

frequently repeated tuberculin tests.

Surgical TreatmentThe recently published nation-wide survey in Great

Britain in 1953 was described. There was much dis-cussion of the optimal duration of chemotherapy beforeoperation. The well-known fact that morbidity wasgreater after resection when the sputum was positive thanwhen it was negative was considered; it was agreed thatthe important factor was the sensitivity of the bacilli-not merely their presence in sputum. The view was putforward that resection could be safely carried out earlyin treatment, after only a few weeks’ chemotherapy,provided that chemotherapy was correctly prescribed andtaken. Possibly earlier resection should indeed be morewidely carried out in cases where it is possible to decideearly that surgery is necessary at all. Certainly individualjudgment was better than a rigid policy. There was alsodifference of opinion about whether thoracoplasty or

resection was desirable in those with resistant organisms.Laboratory tests of respiratory efficiency are probably ofless help in assessing the safety and disabling effects ofoperations than is often believed. Clinical and fluoro-graphic assessment usually gives as good an indication

as laboratory tests. But in " borderline " cases, valuableinformation may sometimes be obtained from them. Itseemed that not more than 10% of the surgical operationsnow done were thoracoplasties. Direct comparisons ofthoracoplasty with resections are not normally valid, forthe types of case selected for the two operations generallydiffer. Furthermore, the follow-up studies are sometimesmeaningless because of the way in which the results arepresented. The immediate risks appeared smaller withthoracoplasty. The loss of function after thoracoplasty isprobably much influenced by the type of operation; and ifan extensive thorough apicolysis is done fewer ribs needbe removed, with less loss of function.

Future Problem of Tuberculosis and its Control

The first stage of the eradication of the disease might bedescribed as its elimination as a critical public-healthproblem; and this might be when no more than 1 % at theage of 14 are tuberculin-positive. This stage has been .

reached in some small areas, but not throughout any onecountry. Mortality and morbidity statistics are of littlevalue for international comparisons. It was suggestedthat these can be made only by properly planned andconducted prevalence surveys using tuberculin tests,X rays, and sputum examinations. As prevalence decreases,only tuberculin surveys will become economic. For suchsurveys a standardised preparation of tuberculin and auniform method of testing must be used. It seemeddesirable to continue collecting data about the reactions tothe higher concentrations of tuberculin and to argue abouttheir exact significance later. Tuberculin surveys give anestimate of the chances of becoming infected in a com-munity and hence an indirectestimate of the prevalence ofinfectious cases. s.c.. vaccination and tuberculin surveysare not incompatible as control measures as long as massvaccination is carried out at a fixed age, such as adoles-cence. It was agreed that B.C.G. vaccination was able toprotect a high proportion for many years. Whether itshould be used as a mass protective measure must bedecided in relation to the known prevalence of the disease.It was stated that in the U.S.A. there was no place formass vaccination.

An important problem existed at present and wouldbecome increasingly difficult to solve: how to arouse andmaintain public interest and cooperation in anti-tubercu-losis measures with a declining danger from the disease.This deserved much careful study in all countries. So didthe important question of how to help people maintainregular self-medication of the anti-tuberculosis drugs,in order to secure their maximum effect in reducinginfection within the community.

ORTHOPaeDICS

A POSTGRADUATE conference on orthopxdics was heldby the Royal Faculty of Physicians and Surgeons ofGlasgow on Nov. 17-21. The subjects included rarefyingdisease of bone, vascular lesions, and the crushed chest.

Rarefying Disease of BoneDr. B. E. C. NORDIN defined osteoporosis as a loss of bone

mass, where the relative proportions of mineral and organicmaterial were preserved. In osteomalacia the mineral contentwas reduced in relation to the organic component, but thesetwo diseases-osteoporosis and osteomalacia-might occur

together. Osteoporosis would not show radiologically until50% of the bone mass was lost; and histologically detection was