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Spring meeting
240
Tubercle, Lond., (1968), 49, 240
BRITISH
TUBERCULOSIS
ASSOCIATION
SPRING MEETING The Spring Meeting of the British Tuberculosis Association in association with the Midland Thoracic Society, the North-Western Thoracic Association and the Sheffield Regional Thoracic Society was held at the University of Keele, Staffordshire on the 5th and 6th April, 1968. The chairmen of the sessions were the President (Dr. F. L. Wollaston), Professor J. G. Scudding, Dr. Dewi Davies, Dr. T. M. Wilson and Dr. V. H. Springett. Dr. C. S. Darke presented his ‘Observations on Bronchiectasis with Radioisotope Scanning of the Pulmonary and Systemic Circulations’. He demonstrated the results on five patients in whom bronchiectasis had been proven, and in whom angiocardiograms and aortograms had been done. Radioactive macroaggregates were injected into the circulation and the lungs scanned both anteriorly and posteriorly. This was an easy tool to employ. As yet, complete interpretation was difficult but areas where effective perfusion occurred were defined, areas of defective perfusion demonstrated and support given to the view that retrograde filling occurred from the bronchial vessels in bronchiectasis. ‘The Management of Cavitating Pneumonia’was discussed by Mr. A. G. Norman. He considered this a febrile illness involving the chest in which the patient deteriorated and from whose sputum Friedlander’s bacillus was isolated as the presumed causative organism, which was usually insensitive to many antiobiotics but sensitive to streptomycin. After a period of six weeks these patients developed a large abscess with persistent foul sputum. Treatment began with postural drainage and antibiotics, but if not successful open drainage with removal of the slough was carried out; if this failed lobectomy was the final treatment of choice. He reported on five cases in which both thoracoplasty and early lobectomy had been used with success. Dr. H. Morrow Brown began his paper on ‘Mites and House Dust Allergy; Treatment by Massive Desensitization’ with a demonstration of the offending mite. He detailed the composition of house dust, the conditions under which the mite flourished and the criteria by which allergy to it was assessed. He described his experiences in attempting desensitization, which in some cases appeared to achieve success, but the present picture and the dosage regimes were at the moment confused. Dr. P. Forgacs presented the Report of a British Tuberculosis Association trial in ‘The Treatment of House Dust Allergy’. Ninety-six patients recruited into the trial were allocated at random into a group given 15 injections of aqueous house dust extract and another given corresponding volumes of O-5% carbol saline. Comparison of the records showed no significant advantage of treatment with house dust extract over the control solution. Patients chosen at random from both the treated and control groups were given advice on how to reduce the amount of house dust in their homes. The progress of patients who received such advice and those who did not was not significantly different. Dr. W. J. H. Leckie reported fully on a ‘Fatal Human Case of Avian Tuberculosis’occurring in an 82 year-old poultry farmer who was shown to have Mycobacterium avium infection in the left upper lobe in 1965. After remaining static for 18 months the disease rapidly extended, resulting in the patient’s death nine months later. The organism was shown to be resistant to twelve antituberculosis drugs and at least partially resistant to erythromycin and cycloserine. The properties of B663 and B749, two riminophenazines to which the organisms was sensitive were also described. The epidemiology of the disease was briefly reviewed and the importance of adequate classification emphasised. The results emanating from the ‘Register of Drug-Resistant Tuberculosis’ were given by Dr. P. A, Jenkins. This register was originally conceived as a means of depicting the epidemiology
BRITISH
TUBERCULOSIS
ASSOCIATION
241
of drug resistance in this country, of investigating the general quality of tuberculosis bacteriology and the diagnosis of drug resistance, and as a method of studying factors in the clinical management of patients which result in the development of resistance. As an epidemiological tool the Register has been disappointing; nevertheless its records indicate that the pool of resistant cases is diminishing. An important benefit has been the exposure of weaknesses in the tuberculosis bacteriology; and from this has resulted the establishment of regional centres to provide expert help in association with the Tuberculosis Reference Laboratory. No general provision has been made for assessing management in cases of drug resistance, but a pilot study in one area has shown that about one-third of cases are primarily resistant, one-third arise from failure of the patients to co-operate and one-third represent possible errors of judgement in chemotherapy management. The impression gained of the quality of current practice is reassuring. Professor D. A. Mitchison discussed the ‘Geographical Variation in the Virulence in the Guinea Pig, the Sensitivity to Thiacetazone and other Characteristics of Tubercle Bacilli’. As a result of tests made on pre-treatment strains from Britain, East Africa, Teheran and several centres in South East Asia, M. tuberculosis can be divided into three types. Type 1, which is characteristic of most British strains, is virulent in the guinea pig, resistant to the bactericidal action of hydrogen peroxide and sensitive to thiacetazone and PAS. Type 2, which is characteristic of many strains from South India, is attenuated in the guinea pig, sensitive to peroxide and resistant to thiacetazone and PAS. Type 3, which is characteristic of strains in Hong Kong, is similar to type 1 but naturally resistant to thiacetazone. Various mixtures of these types existed in the areas from which the strains were received. A close association was found between virulence and peroxide susceptibility. Dr. Stephen Jones described ‘The Findings of Asbestos Bodies in 200 Necropsies in Nottingham, compared with the Findings in Similar Surveys in Other Cities’. Fluid from the cut lung was squeezed on to a slide and thick unstained sections were examined for asbestos bodies. These were found in 8 (4%) of the 200 cases examined from Nottingham and other cities. This survey was part of a larger combined investigation and has helped to establish a base line from which subsequent changes can be measured. It has revealed that asbestos bodies can be found in a large section of the British population, that a higher incidence occurs in mining and port areas, and that the incidence is not high in rural districts. ‘The Control of Pneumoconiosis in the North Staffordshire Pottery Industry’ was discussed by Dr. E. Posner. Evidence from several independent sources strongly suggested a well-marked and recently accelerated decline in newly detected cases of pneumoconiosis in most sections of the industry since 1958. The reason for this decline cannot be sought only in contraction of the industry nor in its partial closure during the last war. Examination of workers who were less than 40 years old when their pneumonoconiosis was detected between 1959 and 1966 revealed that only a minority could have acquired the condition in post-war years. An analysis of female earthenware fettlers suggested that the introduction of improved dust extraction and other measures are now beginning to produce the desired effect. In the earthenware industry, where silica-containing sand is used, cases of pneumoconiosis are still being found. In contrast, pneumoconiosis has ceased to be a problem in china biscuit placing where alumina was substituted for flint 25 years ago. However it still occurs in china potters-shops where flint plays no part in manufacture. Progressive massive fibrosis is now only rarely found in factory workers and the rate has considerably declined in recent years amongst ex-potters. In discussing Pulmonary Embolectomy, Mr. D. B. Clarke mentioned that, although cardiopulmonary bypass was now widely practised, this operation was only possible in centres with this facility available. He described a series of pulmonary embolectomies using an operative technique involving in flow venous occlusion which allowed enough time for exploration of the pulmonary artery and removal of major emboli. Patients were selected for surgery if they had sustained a pulmonary embolus severe enough to impair cardiac output and had evidence of progressive deterioration. Of seven patients operated on, there had been long-term survival in four; deaths in
242
TUBERCLE
the other cases were the result of irreversible brain damage, faecal peritonitis and recurrent pulmonary embolus. Narrowing of the inferior vena cava is now performed at the same time as the embolectomy. Radioactive scanning of the lungs after operation indicated a satisfactory pulmonary blood flow. In reporting on the Surgery of Cardiac Aneurysm, Mr. G. D. Jack enumerated the causes of this condition, of which myocardial infarction was the commonest. The majority of aneurysms are situated towards the apex with or without some area of the related ventricular wall. Most of these are diffuse bulges but some are saccular and the rate of increase of size is no more than O-5 cm. in a year. He listed the clinical features of this condition and the unfavourable prognosis caused by embolic episodes, paradoxical movement of the ventricular wall and the size of the original infarct. He reported on four cases of left ventricular aneurysm successfully treated by surgical excision; three of these were typical, involving the anterior descending branch of the left coronary artery, while the fourth was in a young girl who had suffered an apical infarct early in life. Another report from the Research Committee of the British Tuberculosis Association on ‘A Comparison of the Toxicity of Prothionamide and Ethionamide’was given by Dr. M. E. Schonell. This study was planned as a double blind trial to assess the tolerance of patients and for the liver toxicity of 0.75 g. of prothionamide daily compared with 0.75 g. of ethionamide in the treatment of pulmonary tuberculosis. Patients were also given 300 mg. of isoniazid with either 0.75 g. or 1 g. of streptomycin. Tolerance was assessed by weekly recordings of symptoms and signs and liver toxicity by fortnightly estimations of serum bilirubin and transaminase. Full comprehensive figures of the side effects in the 53 patients receiving prothionamide and 48 ethionamide were given. The results suggested that prothionamide may be slightly better tolerated than ethionamide although the observed differences were not statistically significant. Treatment with either drug carries a risk of liver toxicity and regular liver function tests are advised for all patients treated with these drugs. Squadron Leader D. H. Glaister presented a paper on ‘Chests and Hearts in Space’. In this he considered the chest and heart as a single functional system united by the ventilation-perfusion ratio required for efficient gas exchange. The pulmonary capillaries are unique within the body in being exposed to atmospheric pressure, so that the distribution of pulmonary blood flow within the lung is critically dependent upon hydrostatic pressure gradients. The effects of acceleration stress and weightlessness were considered against this background, and acceleration was shown to lead to extreme inequalities of ventilation and perfusion which culminate in alveolar dead space and alveolar shunt. The shunt was caused by the trapping of gas in dependent lung, the volume of which was reduced by pressure from the weight of the overlying tissue. When oxygen was breathed, areas of trapping became areas of absorptional collapse, and the shunt was less readily reversed. The breathing of oxygen made necessary by the low pressure space suit required for extraventricular activities, introduced the further hazard of fire which was illustrated by a short film of clothing burning under differing pressures of pure oxygen. Weightlessness was shown to offer some theoretical advantages, but since the body is adapted to earth’s gravity the possible loss of such adaptation in space might be critical during the deceleration stress of re-entry. This effect might be exacerbated by a loss of plasma volume. Weightlessness offers the greatest challenge imposed by space travel becuase of the impossibility of simulating the condition satisfactorily on the surface of the earth.
PRINTED
BY GEORGE
OUTRAM
& CO.
LTD.,
36 TAY
STREET,
PERTH,
SCOTLAND
Tubercle, Lond., (1968), 49, 240
BRITISH
TUBERCULOSIS
ASSOCIATION
SPRING MEETING The Spring Meeting of the British Tuberculosis Association in association with the Midland Thoracic Society, the North-Western Thoracic Association and the Sheffield Regional Thoracic Society was held at the University of Keele, Staffordshire on the 5th and 6th April, 1968. The chairmen of the sessions were the President (Dr. F. L. Wollaston), Professor J. G. Scudding, Dr. Dewi Davies, Dr. T. M. Wilson and Dr. V. H. Springett. Dr. C. S. Darke presented his ‘Observations on Bronchiectasis with Radioisotope Scanning of the Pulmonary and Systemic Circulations’. He demonstrated the results on five patients in whom bronchiectasis had been proven, and in whom angiocardiograms and aortograms had been done. Radioactive macroaggregates were injected into the circulation and the lungs scanned both anteriorly and posteriorly. This was an easy tool to employ. As yet, complete interpretation was difficult but areas where effective perfusion occurred were defined, areas of defective perfusion demonstrated and support given to the view that retrograde filling occurred from the bronchial vessels in bronchiectasis. ‘The Management of Cavitating Pneumonia’was discussed by Mr. A. G. Norman. He considered this a febrile illness involving the chest in which the patient deteriorated and from whose sputum Friedlander’s bacillus was isolated as the presumed causative organism, which was usually insensitive to many antiobiotics but sensitive to streptomycin. After a period of six weeks these patients developed a large abscess with persistent foul sputum. Treatment began with postural drainage and antibiotics, but if not successful open drainage with removal of the slough was carried out; if this failed lobectomy was the final treatment of choice. He reported on five cases in which both thoracoplasty and early lobectomy had been used with success. Dr. H. Morrow Brown began his paper on ‘Mites and House Dust Allergy; Treatment by Massive Desensitization’ with a demonstration of the offending mite. He detailed the composition of house dust, the conditions under which the mite flourished and the criteria by which allergy to it was assessed. He described his experiences in attempting desensitization, which in some cases appeared to achieve success, but the present picture and the dosage regimes were at the moment confused. Dr. P. Forgacs presented the Report of a British Tuberculosis Association trial in ‘The Treatment of House Dust Allergy’. Ninety-six patients recruited into the trial were allocated at random into a group given 15 injections of aqueous house dust extract and another given corresponding volumes of O-5% carbol saline. Comparison of the records showed no significant advantage of treatment with house dust extract over the control solution. Patients chosen at random from both the treated and control groups were given advice on how to reduce the amount of house dust in their homes. The progress of patients who received such advice and those who did not was not significantly different. Dr. W. J. H. Leckie reported fully on a ‘Fatal Human Case of Avian Tuberculosis’occurring in an 82 year-old poultry farmer who was shown to have Mycobacterium avium infection in the left upper lobe in 1965. After remaining static for 18 months the disease rapidly extended, resulting in the patient’s death nine months later. The organism was shown to be resistant to twelve antituberculosis drugs and at least partially resistant to erythromycin and cycloserine. The properties of B663 and B749, two riminophenazines to which the organisms was sensitive were also described. The epidemiology of the disease was briefly reviewed and the importance of adequate classification emphasised. The results emanating from the ‘Register of Drug-Resistant Tuberculosis’ were given by Dr. P. A, Jenkins. This register was originally conceived as a means of depicting the epidemiology
BRITISH
TUBERCULOSIS
ASSOCIATION
241
of drug resistance in this country, of investigating the general quality of tuberculosis bacteriology and the diagnosis of drug resistance, and as a method of studying factors in the clinical management of patients which result in the development of resistance. As an epidemiological tool the Register has been disappointing; nevertheless its records indicate that the pool of resistant cases is diminishing. An important benefit has been the exposure of weaknesses in the tuberculosis bacteriology; and from this has resulted the establishment of regional centres to provide expert help in association with the Tuberculosis Reference Laboratory. No general provision has been made for assessing management in cases of drug resistance, but a pilot study in one area has shown that about one-third of cases are primarily resistant, one-third arise from failure of the patients to co-operate and one-third represent possible errors of judgement in chemotherapy management. The impression gained of the quality of current practice is reassuring. Professor D. A. Mitchison discussed the ‘Geographical Variation in the Virulence in the Guinea Pig, the Sensitivity to Thiacetazone and other Characteristics of Tubercle Bacilli’. As a result of tests made on pre-treatment strains from Britain, East Africa, Teheran and several centres in South East Asia, M. tuberculosis can be divided into three types. Type 1, which is characteristic of most British strains, is virulent in the guinea pig, resistant to the bactericidal action of hydrogen peroxide and sensitive to thiacetazone and PAS. Type 2, which is characteristic of many strains from South India, is attenuated in the guinea pig, sensitive to peroxide and resistant to thiacetazone and PAS. Type 3, which is characteristic of strains in Hong Kong, is similar to type 1 but naturally resistant to thiacetazone. Various mixtures of these types existed in the areas from which the strains were received. A close association was found between virulence and peroxide susceptibility. Dr. Stephen Jones described ‘The Findings of Asbestos Bodies in 200 Necropsies in Nottingham, compared with the Findings in Similar Surveys in Other Cities’. Fluid from the cut lung was squeezed on to a slide and thick unstained sections were examined for asbestos bodies. These were found in 8 (4%) of the 200 cases examined from Nottingham and other cities. This survey was part of a larger combined investigation and has helped to establish a base line from which subsequent changes can be measured. It has revealed that asbestos bodies can be found in a large section of the British population, that a higher incidence occurs in mining and port areas, and that the incidence is not high in rural districts. ‘The Control of Pneumoconiosis in the North Staffordshire Pottery Industry’ was discussed by Dr. E. Posner. Evidence from several independent sources strongly suggested a well-marked and recently accelerated decline in newly detected cases of pneumoconiosis in most sections of the industry since 1958. The reason for this decline cannot be sought only in contraction of the industry nor in its partial closure during the last war. Examination of workers who were less than 40 years old when their pneumonoconiosis was detected between 1959 and 1966 revealed that only a minority could have acquired the condition in post-war years. An analysis of female earthenware fettlers suggested that the introduction of improved dust extraction and other measures are now beginning to produce the desired effect. In the earthenware industry, where silica-containing sand is used, cases of pneumoconiosis are still being found. In contrast, pneumoconiosis has ceased to be a problem in china biscuit placing where alumina was substituted for flint 25 years ago. However it still occurs in china potters-shops where flint plays no part in manufacture. Progressive massive fibrosis is now only rarely found in factory workers and the rate has considerably declined in recent years amongst ex-potters. In discussing Pulmonary Embolectomy, Mr. D. B. Clarke mentioned that, although cardiopulmonary bypass was now widely practised, this operation was only possible in centres with this facility available. He described a series of pulmonary embolectomies using an operative technique involving in flow venous occlusion which allowed enough time for exploration of the pulmonary artery and removal of major emboli. Patients were selected for surgery if they had sustained a pulmonary embolus severe enough to impair cardiac output and had evidence of progressive deterioration. Of seven patients operated on, there had been long-term survival in four; deaths in
242
TUBERCLE
the other cases were the result of irreversible brain damage, faecal peritonitis and recurrent pulmonary embolus. Narrowing of the inferior vena cava is now performed at the same time as the embolectomy. Radioactive scanning of the lungs after operation indicated a satisfactory pulmonary blood flow. In reporting on the Surgery of Cardiac Aneurysm, Mr. G. D. Jack enumerated the causes of this condition, of which myocardial infarction was the commonest. The majority of aneurysms are situated towards the apex with or without some area of the related ventricular wall. Most of these are diffuse bulges but some are saccular and the rate of increase of size is no more than O-5 cm. in a year. He listed the clinical features of this condition and the unfavourable prognosis caused by embolic episodes, paradoxical movement of the ventricular wall and the size of the original infarct. He reported on four cases of left ventricular aneurysm successfully treated by surgical excision; three of these were typical, involving the anterior descending branch of the left coronary artery, while the fourth was in a young girl who had suffered an apical infarct early in life. Another report from the Research Committee of the British Tuberculosis Association on ‘A Comparison of the Toxicity of Prothionamide and Ethionamide’was given by Dr. M. E. Schonell. This study was planned as a double blind trial to assess the tolerance of patients and for the liver toxicity of 0.75 g. of prothionamide daily compared with 0.75 g. of ethionamide in the treatment of pulmonary tuberculosis. Patients were also given 300 mg. of isoniazid with either 0.75 g. or 1 g. of streptomycin. Tolerance was assessed by weekly recordings of symptoms and signs and liver toxicity by fortnightly estimations of serum bilirubin and transaminase. Full comprehensive figures of the side effects in the 53 patients receiving prothionamide and 48 ethionamide were given. The results suggested that prothionamide may be slightly better tolerated than ethionamide although the observed differences were not statistically significant. Treatment with either drug carries a risk of liver toxicity and regular liver function tests are advised for all patients treated with these drugs. Squadron Leader D. H. Glaister presented a paper on ‘Chests and Hearts in Space’. In this he considered the chest and heart as a single functional system united by the ventilation-perfusion ratio required for efficient gas exchange. The pulmonary capillaries are unique within the body in being exposed to atmospheric pressure, so that the distribution of pulmonary blood flow within the lung is critically dependent upon hydrostatic pressure gradients. The effects of acceleration stress and weightlessness were considered against this background, and acceleration was shown to lead to extreme inequalities of ventilation and perfusion which culminate in alveolar dead space and alveolar shunt. The shunt was caused by the trapping of gas in dependent lung, the volume of which was reduced by pressure from the weight of the overlying tissue. When oxygen was breathed, areas of trapping became areas of absorptional collapse, and the shunt was less readily reversed. The breathing of oxygen made necessary by the low pressure space suit required for extraventricular activities, introduced the further hazard of fire which was illustrated by a short film of clothing burning under differing pressures of pure oxygen. Weightlessness was shown to offer some theoretical advantages, but since the body is adapted to earth’s gravity the possible loss of such adaptation in space might be critical during the deceleration stress of re-entry. This effect might be exacerbated by a loss of plasma volume. Weightlessness offers the greatest challenge imposed by space travel becuase of the impossibility of simulating the condition satisfactorily on the surface of the earth.
PRINTED
BY GEORGE
OUTRAM
& CO.
LTD.,
36 TAY
STREET,
PERTH,
SCOTLAND