Radiographic knee osteoarthritis in floorlayers and carpenters

OBJECTIVES

The aim of the present study was to examine the relationship between knee-straining work and radiological findings of knee osteoarthritis and to study the relation between radiological findings and self-reported knee complaints and clinical signs of knee osteoarthritis.

METHODS

The material consisted of 133 floorlayers, 506 carpenters, and 327 compositors, 26-72 years of age, who had completed a questionnaire and reported no previous knee trauma. A stratified sample of these questionnaire respondents, 50 floorlayers, 51 carpenters, and 49 compositors, were radiologically examined for knee osteoarthritis by 2 radiologists. The X-ray films were independently assessed by 2 radiologists and blinded with respect to knee complaints, trade, and age.

RESULTS

The radiological investigation showed estimated prevalences of knee-osteoarthritis (grades 2-4) for 14% of the floorlayers, 8% of the carpenters, and 6% of the compositors (not significantly different). For the subjects > or =50 years of age the estimated prevalences of the combination of radiological grades 2-4 for knee osteoarthritis and knee complaints during the last 12 months were 29% [95% confidence interval (95% CI) 17-44%], 9% (95% CI 1-26%), and 1% (95% CI 1-10%) for the floorlayers, carpenters, and compositors, respectively. Radiological grades 2-4 were mainly found for subjects above the age of 50 years, subjects with knee complaints, and floorlayers. Radiological knee osteoarthritis was positively associated with self-reported knee complaints and with clinical signs of intraarticular and retropatellar crepitation.

CONCLUSIONS

The data suggest that work in which a considerable amount of time is spent in knee-straining positions may be a risk factor for the development of knee osteoarthritis above the age of 50 years.

Fire eater's pneumonia: radiographic and CT findings

Acute aspiration of petroleum by fire eaters can cause a distinct type of chemical pneumonitis known as fire eater's pneumonia that manifests on radiologic studies with unilateral or bilateral lung consolidations, well defined nodules, and pneumatoceles. We report three cases of fire eater's pneumonia that manifested with well-defined cavitary nodules (pneumatoceles) on radiographs and CT. One patient developed a bronchopleural fistula and spontaneous pyopneumothorax. CT is valuable for identifying and localizing complications to guide therapy.

Pulmonary fibrosis in a steel mill worker

We report a case of pulmonary fibrosis in a 32-year-old man, who had worked at a steel mill and who died of respiratory failure due to interstitial fibrosis despite vigorous treatment. He showed SLE-associated symptoms, such as pleural effusion, malar rashes, discoid rashes, arthritis, leukopenia, and positive antinuclear antibody and anti-histone antibody. However, he did not present anti-DNA antibody. A thoracoscopic lung biopsy showed interstitial fibrosis, chronic inflammation and a small non-caseating granuloma in lung tissues, which could be induced by external agents such as metals. The manganese concentration in the lung tissue was 4.64 microg/g compared to 0.42-0.7 microg/g in the controls. The levels of other metals, such as iron, nickel, cobalt and zinc in patient's lung tissue were higher than those in the controls. The patient was probably exposed to Si and various metal dusts, and the lung fibrosis was related to these exposures. Exposure to Si and metal dusts should be sought in the history of any patient with SLE, especially in a male with pulmonary signs, and if present, exposure should be stopped. In the meantime, steps should be taken to ensure that workers exposure to Si and metal dusts in all environments have adequate protection.

Debridement arthroplasty for osteoarthrosis of the elbow: 50 patients followed mean 5 years

The characteristics and surgical outcome of debridement arthroplasty were investigated in athletes and manual laborers with osteoarthrosis of the elbow. There were 26 elbows in athletes, and 24 elbows in laborers. The mean age was 32 years in athletes and 50 years in laborers. The osteoarthrosis was mainly mild in athletes, but moderate or severe in laborers. Debridement arthroplasty, consisting of resection, osteophytes and removal of loose bodies, was performed in all cases. The medial approach was most frequently employed. Surgery relieved pain and improved range of motion at an average follow-up of 59.5 months. Evaluation of the long-term outcomes at more than 5 years showed recurrence of mild osteoarthrosis with minimal symptoms. Debridement arthroplasty is an effective treatment in athletes and manual laborers with osteoarthrosis of the elbow.

Characteristics of coronary heart disease in Japanese taxi drivers as determined by coronary angiographic analyses

Several epidemiological studies have shown that the prevalence of ischemic heart disease is higher in occupational drivers than in people with other occupations. Although occupation categories can be surrogate measures for coronary risk factors, the relationships between taxi driving and severity of coronary heart disease (CHD) has not been investigated. Even more important, the contribution of risk factors to the severity of CHD in taxi drivers remains unclear. Our study tested the hypothesis that taxi driving could be associated with the severity of CHD. We also examined the relation between this occupation and risk factors and social lifestyle. We analyzed the coronary angiograms of 57 consecutive male taxi driver patients and compared them with those of 215 age-adjusted male non-taxi-driver patients. The number of diseased vessels and risk factors were compared between two groups. The prevalence of myocardial infarction and multi-vessel disease was higher in the taxi-driver patients than in the non-taxi-driver patients. The taxi-driver patients had higher prevalence of body mass index (BMI), diabetes, and smoking, higher levels of low-density lipoprotein cholesterol (LDL-C), and lower levels of apolipoprotein AI (ApoAI). Multiple logistic regression analysis showed that multi-vessel disease was associated with BMI and diabetes mellitus in taxi-driver patients. The taxi-driver patients were characterized by more extensive coronary atherosclerosis associated with higher prevalence of diabetes mellitus and obesity. These characteristics may be explained by in part their working environment.

Flock worker's lung: broadening the spectrum of clinicopathology, narrowing the spectrum of suspected etiologies

STUDY OBJECTIVES

Workers in the nylon flocking industry recently have been found to be at increased risk of chronic nongranulomatous interstitial lung disease. Although a spectrum of cytologic and histopathologic abnormalities has been observed, nonspecific interstitial pneumonia, lymphoid nodules, and lymphocytic bronchiolitis predominated in the 19 previously reported cases of flock worker's lung. Here we describe five additional patients who appear to expand the histopathologic spectrum and add to the evidence suggesting a causative role for respirable-sized nylon fragments.

METHODS

We studied all North American patients (n = 5) found in 1998 to satisfy our previous case definition of flock worker's lung. Two pulmonary pathologists independently reviewed each biopsy specimen.

RESULTS

All five patients reported cough and dyspnea. Only one patient had crackles on chest auscultation. High-resolution CT scan, interpreted with attention to subtle ground-glass attenuation, remained a highly sensitive diagnostic test. Pulmonary function tests and plain chest radiograph were less sensitive. One patient's wedge biopsy showed previously described prototypical findings. Two others had transbronchial biopsies showing some of the same features. The fourth patient's wedge biopsy showed desquamative interstitial pneumonia. The fifth patient had bilateral synchronous adenocarcinoma but with radiographic evidence of diffuse interstitial fibrosis. These 5 patients and the 19 patients studied previously were exposed to nylon flock manufactured by a rarely used cutting technology.

CONCLUSION

Findings in these five patients appear to broaden the spectrum of the clinicopathology of flock worker's lung and add to the evidence incriminating respirable-sized nylon particulates produced during the manufacture and use of rotary-cut nylon flock.

Occupational physical demands and hip osteoarthritis

The authors investigated the influence of physical strain at work on radiological signs of hip osteoarthritis. The study included 295 men and 298 women aged over 45 from an urban area who were classified in four groups according to physical demands of their occupation. The evaluation included clinical and radiological signs of hip osteoarthritis. The association between hip osteoarthritis and occupation was analysed using logistic regression. Though not significantly, radiological signs of hip osteoarthritis were common in subjects who worked in a standing position (odds 1.45 for men, 1.50 for women). Clinical signs of osteoarthritis in women were significantly associated with performance in a standing position (odds 3.00), whereas in men the association was more significant for jobs with high physical strain (odds 2.19). There was a sustained trend toward an increase in health risk with years of work in all job categories. Occupation did not appear to influence the development of radiological hiposteoarthritis, but the authors did establish association between clinical signs of hip osteoarthritis and work.

Beekeeper' arthropathy

OBJECTIVE

To describe the clinical, analytical, and radiological features of an observed arthropathy affecting beekeepers.

METHODS

Prospective study of 34 patients (32 male, 2 female), mean age 42 years (range 16 to 66 years), evaluated for the presence of acute or chronic arthritis related to beekeeping. All patients were working and living in the same village, Fuenlabrada de los Montes (1300 habitants), where there is a census of 180 beekeepers. An epidemiologic inquiry reported that > 50% of them reported episodes of arthritis on the hands during the month of August, at the time of honey collection.

RESULTS

Acute arthritis was observed in 10 patients. Pain, tenderness, joint swelling, and warmth were present in most cases. Chronic arthropathy was noted in 32 patients. Tenderness was present in 16 cases, synovial thickening in 12, limited joint mobility in 8, bony swelling in 15, and joint deformities in 13 patients. Radiological study showed periarticular soft tissue swelling, bone sclerosis, periostitis, bony erosions, subchondral cysts, geodes, osteophytes, and joint narrowing.

CONCLUSION

Beekeepers have joint disease apparently related to bee stings. Etiopathogenesis is unknown. Mechanical trauma, venom compounds, infection, and foreign body synovitis are factors that are thought to influence the pathogenesis of this syndrome. We designate the condition "beekeepers' arthropathy," and consider it an occupational disorder.

Repetitive high G exposure is associated with increased occurrence of cardiac valvular regurgitation

BACKGROUND

Exposure to repeated high +Gz loads and the methods to prevent loss of consciousness cause unique stresses on the cardiovascular system. The purpose of this study was to determine if the +Gz environment is associated with an increased occurrence of valvular regurgitation in pilots of high performance aircraft.

METHODS

There were 247 subjects who were divided into pilot (n = 46) and non-pilot (n = 201) groups. Pilots were defined as those individuals who had flown at least 1000 h in high performance aircraft. The echocardiographic data of these subjects were examined retrospectively.

RESULTS

We found a statistically significant association between pulmonic insufficiency and exposure to high +Gz stress in pilots vs. non-pilots (chi2 = 13.09, p = 0.0002). In addition, there was a greater incidence of tricuspid regurgitation (chi2 = 4.97, p = 0.025) and concurrent pulmonic insufficiency and tricuspid regurgitation (chi2 = 14.1, p = 0.0002) in the pilot group.

CONCLUSIONS

There is a direct relationship between repetitive exposure to a +Gz environment and pulmonic insufficiency, tricuspid regurgitation, or concurrent pulmonic insufficiency and tricuspid regurgitation. This may be secondary to the transient increase in right ventricular pressure due to acceleration forces or straining maneuvers utilized to prevent or postpone +Gz induced loss of consciousness (G-LOC).

Evaluation of the impingement of the pronator muscle in occupational carpal tunnel syndrome by electromyographic and ultrasonographic techniques

Normal flexion of the fingers involves an involuntary contraction of the pronator and lumbrical muscle. In individuals whose profession involves constant flexing of the fingers those muscles become hypertrophied, impinging on the carpal tunnel. The narrowing of the carpal tunnel yields well to ultrasonography. The objective of this investigation was to find an ultrasonographic index of occupational carpal tunnel syndrome. Thus "Index M" denotes the variation obtained in the "M Space" before and after flexion-extension of the fingers. The study included 45 subjects performing tasks which involved the risk of cumulative trauma disorders. The subjects were tested using the electromyography and ultrasonography. The method was based on relation between the decrease in conduction of the median nerve measured by electromyography and the ultrasonographically measured variation of "M Space" in terms of sensitivity and specificity. The sensitivity of ultrasonography was 85%, as it confirmed the pathologic findings determined by electromyography ("M Index" positive) in twenty-two out of 26 hands, but the specificity was not statistically significant. Ultrasonography seems to have found very important application as a screening technique in occupational medicine. It is non-invasive, sensitive, easily repeated, and costs little.

Degenerative changes of the spine of fighter pilots of the Royal Netherlands Air Force (RNLAF)

HYPOTHESIS

The aim of this study was to examine whether F-16 pilots are at an increased risk of (cervical) spine degeneration.

METHOD

Retrospectively, X-ray slides were examined of pilots of the Royal Netherlands Air Force who were systematically radiographed (at least twice). In total, 316 pilots were evaluated: 188 F-16 pilots and 128 pilots in the control group. Two radiologists, who were blinded as to whether the X-ray films were of F-16 pilots or the control group, examined these X-rays separately. In both groups, the time between the two X-rays was on average 6 yr.

RESULTS

Though the inter-rater agreement of the X-rays was rather low, both radiologists found comparable statistically significant differences between the two groups. In the F-16 group, an increased osteophytic spurring was found at levels C4-C5 and C6-C7, and increased arthrosis deformans was found in the cervical spine. Further analysis of the data of a selected group of pilots, whereby the difference in age between both groups was minimized, showed that the higher mean age of the F-16 pilots was possibly correlated with the increased degeneration in this group. No consistent relationship was found between spinal degeneration and initial radiological status. Also, a clear relationship between spinal degeneration and flying hours could not be demonstrated.

CONCLUSION

These findings suggest that frequent exposure to high +Gz forces might cause premature degeneration of the spine of F-16 pilots. Future research must demonstrate to what extent age, mission, and number of flying hours have influenced the results. An uniform international classification and coding system in combination with establishing an international database is recommended.

The prevalence of left ventricular hypertrophy in elite professional footballers

BACKGROUND

We evaluated the prevalence of left ventricular hypertrophy in elite footballers compared with sedentary controls. A total of 141 elite male professional footballers and 32 healthy sedentary controls were studied. Echocardiographic and demographic variables were compared between groups by unpaired t-test.

RESULTS

The prevalence of left ventricular hypertrophy with maximal wall thickness values out with the normal range (>12 mm) was noted. Footballers were significantly younger than controls (20.9 vs. 24.3 years, P<0.005: 95% CI (-5.2, -1.73)) but there were no significant differences in height, weight or body surface area between the groups. Each of inter-ventricular septum (10.4 vs. 9.1 mm, P<0.0001; 95% CI (0.88, 1.72)), posterior wall (9.2 vs. 8.5 mm, P<0.01; 95% CI (0.22, 1.21)), left ventricular cavity (systolic and diastolic) (34.5 vs. 28.4 mm, P<0.0001; 95% CI (4.31, 7.76) in systole; 50.1 vs. 48.2 mm, P<0.05; 95% CI (0.15, 3.74) in diastole), aortic root size (29.1 vs. 27.8 mm, P<0.05; 95% CI (0.03,2.49)) and left ventricular mass index (112 vs. 89 g/m2, P<0.0001; 95% CI (14.4, 32.1)) were significantly greater in footballers than in controls. Absolute left ventricular wall thickness >12 mm was present in 17 footballers (12%) (range 13-15 mm) and in no controls.

CONCLUSIONS

Elite professional footballers have increased cardiac dimensions compared with healthy controls. The prevalence of absolute wall thicknesses out with the normal range is relatively high.

The contribution of bone scintigraphy in occupational health or medical insurance claims: a retrospective study

Patients with a suspicion of bone damage following an industrial or traffic accident are often referred for bone scintigraphy as part of an occupational health or medical insurance investigation. The aim of this study was to assess the contribution and the potential role of bone scintigraphy compared with X-ray investigations in the aforementioned situation. To this end we evaluated 70 consecutive patients referred for bone scintigraphy during 1996 and 1997 by occupational health or medical insurance physicians. The most common reasons for referral were the exclusion of occult fractures of hands and feet, whiplash injuries, reflex sympathetic dystrophy or avascular necrosis, or the differentiation between an old and a recent vertebral fracture. X-rays were only available for comparative review of 53 patients, so only those were analysed. The results of bone scintigraphy were compared with X-rays, and their contribution and potential role in occupational health or medical insurance investigations assessed. In 31 out of the 53 patients investigated, bone scintigraphy findings concurred with X-rays as to the number and location of abnormalities. For 19 of the 53 patients, bone scintigraphy showed clinically relevant additional foci when compared with X-rays, predominantly involving lesions to hands/wrists and feet/ankles. Among these 19 patients, scintigraphic diagnoses were subsequently confirmed in ten cases by means of X-ray or computed tomography. In four patients, supplementary radiological investigations revealed no abnormalities, and in five patients no further investigations were undertaken. Finally, in three of the 53 patients, X-rays revealed bone damage (burst fractures) whilst the corresponding bone scintigraphy was negative, thus excluding recent injury. In conclusion, in 22 patients, representing 42% of the cases analysed, bone scintigraphy was conclusive compared with X-ray imaging in the final diagnosis and in this way in detecting occult or excluding active bone damage after a traffic or industrial accident. This makes bone scintigraphy a useful investigation in situations where a full or partial disablement claim has to be confirmed, extended or terminated.

Hyperhomocysteinaemia and upper extremity deep venous thrombosis: a case report

A case is presented of a 24 yr old military aircrew applicant who developed a right axillary subclavian deep venous thrombosis following physical exertion. Investigations revealed damage to the right axillary subclavian venous system and limitation to flow. Coagulation studies also showed an elevated plasma homocysteine level. Hyperhomocysteinemia has recently been recognized as a risk factor for venous thromboembolic disease. Damage caused by the thrombosis, the hyperhomocysteinemia and environmental factors encountered in flight, may predispose him to recurrent episodes of thrombosis. This complex case involves aspects of hematology and the nature of coagulation which are only just being elucidated and as yet are poorly understood, and highlights some serious aeromedical implications for pilots afflicted with these conditions.

An operative procedure for advanced Kienböck's disease. Excision of the lunate and subsequent replacement with a tendon-ball implant

Excision of the lunate and subsequent replacement with a tendon implant was performed in 22 patients with Kienböck's disease between 1971 and 1985. This procedure was indicated mainly for those with advanced Kienböck's disease, i.e., stage III or IV according to the Lichtman classification. After the collapsed lunate is removed, a tendon-ball implant, made of the palmaris longus and plantaris tendons is placed in the resultant space in the carpus. A forearm distractor is applied during the operation, and distraction is continued for 4 weeks postoperatively. We report the long-term results in 15 patients, whose average follow-up period was 16 years and 3 months. One patient with infection was excluded from the study because the implanted tendon was removed 2 weeks after the operation, and 6 patients were lost to follow-up. All patients were free of pain after the surgery. The flexion-extension range of the wrist increased by 14.2 degrees, on average, after the surgery. The average grip power of the operated hand was 90.2% of that in the non-operated hand. Calcification and ossification were frequent in the implanted tendons a few months postoperatively. The average carpal height ratio (defined as carpal height/length of the third metacarpal) was 0.53 before the operation and 0.49 at the time of follow-up. According to Dornan's classification of clinical results, 9 of the 15 patients were classified as having excellent results and 6 as good.

Nylon flock-associated interstitial lung disease

A work-related interstitial lung disease has been diagnosed in workers at five nylon flock facilities in three different states and a Canadian province. The National Institute for Occupational Safety and Health hosted a workshop at which consulting pulmonary pathologists reviewed lung tissue samples from all the cases for which lung biopsy material was available (15 of 20 cases known in January 1998). After independent review and scoring of these lung tissue specimens, the pathologists reached consensus that the histopathological findings revealed a characteristic lesion-a lymphocytic bronchiolitis and peribronchiolitis with lymphoid hyperplasia represented by lymphoid aggregates. The pathologists noted that the pathological findings were distinctive when compared with known lung conditions. The clinical presentation for the cases generally included cough, dyspnea, restrictive ventilatory defect with reduction in diffusing capacity, and interstitial markings on chest radiographs or high-resolution computed tomography (HRCT) scans. Six of the cases improved after removal from workplace exposure without medical treatment. Six others, who had recovered with medical treatment and removal from the workplace, had relapses in both symptoms and objective findings after attempting to return to nylon flock work. With this and other evidence supporting the existence of chronic interstitial pneumonitis associated with nylon flock processing, workshop participants recommended surveillance for early identification of affected workers and their removal from further workplace exposure.

[Development of vibration-induced intrahepatic cholestasis in pilots and new ways of correcting these disorders]

Data of analysis of the role of vibration in the development of hepatobiliary pathology in helicopter pilots are reported. Vibration was found to drastically deteriorate colloid-osmotic qualities of the bile and increase the lithogenesis risk. Exposure to vibration over 10 and more years of the flying career may instigate cholelithiasis. Dynamic USI with functional testing for early diagnostics and correction with ursodeoxycholic acid (ursosan) of disorders in the colloid-osmotic properties of the bile and can be proposed as one of the methods to prevent cholelithiasis.

Periodontal bone height in professional musicians. Cross-sectional and longitudinal aspects

Cross-sectional and longitudinal studies of the periodontal bone height were performed on professional musicians playing wind and non-wind instruments. The cross-sectional study population included 244 occupational musicians (186 men and 58 women aged 20-69 years) from three Swedish national orchestras. Eighty-seven were wind instrument musicians. Radiographic full-mouth surveys were performed and the periodontal bone height was measured with a computerized method and expressed as a percentage of the root length. The mean periodontal bone height was 83.4% for the musicians playing wind instruments and 83.6% for those playing non-wind instruments. There was no statistically significant difference in periodontal bone height between the two instrumentalist categories. In addition, the bone height quotients of anterior to posterior teeth were analyzed but no significant differences were found between wind and non-wind instrumentalists. A longitudinal cohort including 92 musicians who had been examined in a corresponding study 10 years earlier was studied. The overall loss of the periodontal bone height over the 10-year period was small, but only wind instrumentalists of the 50-69 year age group exhibited a statistically significant reduction over time. There was no statistically significant difference between musicians as regards instrument played. It is concluded from the cross-sectional and 10-year longitudinal observations that the playing of wind instruments is unlikely to affect periodontal bone height.

The human pericardium in vibroacoustic disease

INTRODUCTION

One of the main features of vibroacoustic disease (VAD) is the proliferation of the extra-cellular matrix which induces cardiovascular morphological and dynamic changes, and has been evaluated through echo-Doppler. While all subjects exposed to large pressure amplitude (> or =90 dB SPL) and low frequency (< or =500 Hz) (LPALF) for at least 15 yr have thickening of some cardiac structure, most frequently the pericardium, no significant diastolic changes accompany these observations. Echocardiography has become the diagnostic method of choice for the VAD. However, there have been no studies relating the echo-images of pericardial thickening to gross anatomy.

METHODS

We present the histology and ultrastructure of the pericardia of four patients who underwent cardiac surgery.

RESULTS

The most important findings concern the real thickening of the pericardium (values: 1.11, 1.35, 2.19, and 2.33 mm vs. norm: < or = 0.5 mm), the dynamic arrangements of mesothelial cells in the serosa layer, and the plasticity of the cells found among the multifascicular waveform collagen fibers. We found that the fibrosa of VAD patients has three layers: sandwiched between two thickened layers of normal fibrosa there is a loose tissue layer with vascular, nervous, and adipose structures.

CONCLUSION

These features may partially explain why no important diastolic changes are observed in VAD patients in spite of the pericardium thickening.

Echocardiographic evaluation in 485 aeronautical workers exposed to different noise environments

INTRODUCTION

Vibroacoustic disease (VAD) is a heterogeneous and systemic entity, caused by long term (> or =10 yr) exposure to noise environments characterized by large pressure amplitude and low frequency (LPALF) (> or =90 dB SPL, < or = 500 Hz), and not explained by other possible etiologic agents. The goal of this study was to identify possible structural changes in hearts of men with suspected VAD.

METHODS

A total of 485 men were divided into 3 noise groups: no noise exposure (< or =70 dB), n = 48 (Group I); moderate noise exposure, (>70dB and < 90 dB), n = 113 (Group II); and intense noise exposure (> or =90 dB), n = 324 (Group III). Echo-Doppler studies were performed (HP SONOS 1500) and recorded on coded videotapes. Three observers performed blinded evaluations of 26 echo-Doppler parameters. For the purpose of the present study only 12 morphological parameters were compared among the groups: thickening of the mitral, aortic, tricuspid, and pulmonary valves, pericardium and endocardium; mitral valve regurgitation, prolapse and ruptured chordae tendinae; and inflow velocities. Thickness and severity of the applicable parameters were scored in seven-grade scale (0,0.5,1, ...,3).

RESULTS

All evaluated parameters were statistically significantly different in Group I vs. Group III, except flow velocity E. Comparison of Group I vs. Group II revealed statistically significant differences in mitral, aortic, tricuspid and pericardial thickening, with the strongest evidence for mitral and pericardial structures.

CONCLUSIONS

This confirms the results of previous studies. Occupational exposure to noise environments characterized by LPALF noise causes structural changes in the heart. Mitral valve and pericardial thickening constitute the first signs of VAD.

Risks of respiratory disease in the heavy clay industry

OBJECTIVES

Little information is available on the quantitative risks of respiratory disease from quartz in airborne dust in the heavy clay industry. Available evidence suggested that these risks might be low, possibly because of the presence in the dust of other minerals, such as illite and kaolinite, which may reduce the harmful effects of quartz. The aims of the present cross sectional study were to determine among workers in the industry (a) their current and cumulative exposures to respirable mixed dust and quartz; (b) the frequencies of chest radiographic abnormalities and respiratory symptoms; (c) the relations between cumulative exposure to respirable dust and quartz, and risks of radiographic abnormality and respiratory symptoms.

METHODS

Factories were chosen where the type of process had changed as little as possible during recent decades. 18 were selected in England and Scotland, ranging in size from 35 to 582 employees, representing all the main types of raw material, end product, kilns, and processes in the manufacture of bricks, pipes, and tiles but excluding refractory products. Weights of respirable dust and quartz in more than 1400 personal dust samples, and site histories, were used to derive occupational groups characterised by their levels of exposure to dust and quartz. Full size chest radiographs, respiratory symptoms, smoking, and occupational history questionnaires were administered to current workers at each factory. Exposure-response relations were examined for radiographic abnormalities (dust and quartz) and respiratory symptoms (dust only).

RESULTS

Respirable dust and quartz concentrations ranged from means of 0.4 and 0.04 mg.m-3 for non-process workers to 10.0 and 0.62 mg.m-3 for kiln demolition workers respectively. Although 97% of all quartz concentrations were below the maximum exposure limit of 0.4 mg.m-3, 10% were greater than this among the groups of workers exposed to most dust. Cumulative exposure calculations for dust and quartz took account of changes of occupational group, factory, and kiln type at study and non-study sites. Because of the importance of changes of kiln type additional weighting factors were applied to concentrations of dust and quartz during previous employment at factories that used certain types of kiln. 85% (1934 employees) of the identified workforce attended the medical surveys. The frequency of small opacities in the chest radiograph, category > or = 1/0, was 1.4% (median reading) and seven of these 25 men had category > or = 2/1. Chronic bronchitis was reported by 14.2% of the workforce and breathlessness, when walking with someone of their own age, by 4.4%. Risks of having category > or = 0/1 small opacities differed by site and were also influenced by age, smoking, and lifetime cumulative exposure to respirable dust and quartz. Although exposures to dust and to quartz were highly correlated, the evidence suggested that radiological abnormality was associated with quartz rather than dust. A doubling of cumulative quartz exposure increased the risk of having category > or = 0/1 by a factor of 1.33. Both chronic bronchitis and breathlessness were significantly related to dust exposure.

CONCLUSIONS

Although most quartz concentrations at the time of this study were currently below regulatory limits in the heavy clay industry, high exposures regularly occurred in specific processes and occasionally among most occupational groups. However, there are small risks of pneumoconiosis and respiratory symptoms in the industry, although frequency of pneumoconiosis is low in comparison to other quartz exposed workers.

Tibial lead determination by99Tcmradiopharmaceutical X-ray fluorescence

The feasibility of measuring tibial lead concentration by x-ray fluorescence with an internal 99Tcm labelled bone-seeking radiopharmaceutical was investigated using phantoms containing known values of lead concentration and 99Tcm activity. The minimum detectable concentration (MDC) at two standard deviations based on the counts in the Kalpha1 peak of 10.9 microg Pb ml(-1) was estimated to correspond to an MDC for an individual within a range of approximately 8-15 microg Pb (g bone mineral)(-1) if the counts from all four K x-ray peaks were included. Due to its much greater dose compared to an external source, the MDC of this internal source technique would have to be reduced before it could be used for measurements of occupationally or environmentally exposed individuals other than as an adjunct for a patient undergoing a bone scan. Methods of achieving such a reduction include increasing the acquisition time and the number of HPGE detectors, and optimizing the design of their collimators.

Cerebral vasoreactivity by transcranial Doppler in carbon disulfide poisoning cases in Korea

The abnormalities of cerebral vasoreactivity were evaluated in CS2 poisoning cases. In 34 retired workers with CS2 poisoning (case group) and 20 healthy individuals (control group), blood flow velocities were measured in the middle cerebral arteries (MCA) by transcranial Doppler. Compared with the control group, the case group showed lower mean values of blood flow velocities and pulsatile indices. The differences in CO2 reactivities of both groups were remarkable (1.10-2.19% decrease/mmHg CO2 for cases and 3.35-5.08 for controls). Multiple regression analyses were conducted to adjust the effect of age, sex, and exposure level (non-low-high exposure) to CO2 reactivity and pulsatile index. The exposure level was statistically significant in the regression model for CO2 reactivity of both MCA and for pulsatile index of the right MCA. Our study noted a decrease of CO2 reactivity and pulsatile index of cerebral vessels related with CS2 exposure. These findings suggested that CS2 exposure could lead to a decrease of cerebral vasoreactivities by the atherosclerotic change of cerebral vessels.

Transient ischemic attacks caused by trumpet playing

We report a young musician who experienced transient ischemic attacks during trumpet playing. Cardiovascular examination revealed a patent foramen ovale; Doppler ultrasound of the middle cerebral arteries detected microembolic signals with increased rates during trumpet playing and Valsalva maneuver. After operative occlusion of the foramen ovale, the symptoms disappeared and no microembolic signals could be detected.

[Radiological evidence of involvement of dust exposure in pathogenesis of pulmonary alveolar proteinosis]

A 52-year-old man was admitted because of increasing dyspnea on exersion and presence of pulmonary infiltrates. The patient had pulmonary tuberculosis at the age of 31, which resulted in volume loss and calcified foci in the upper lobe of his left lung. As a construction worker for more than 20 years, he had been exposed to inorganic dusts. Chest radiographs showed a symmetrical consolidation of infiltrates in both lungs with the exception of the left upper lobe, where no apparent infiltrates were shown. A computed tomographic scan of the chest revealed widely panlobular consolidation with the exception of the left upper lobe. A diagnosis of pulmonary alveolar proteinosis (PAP) was established by analysis of bronchoalveolar lavage fluid. Although the patient underwent segmental bronchoalveolar lavage four times under general anesthesia, he suffered frequent pulmonary infection and died two years after the onset his symptoms. Interestingly, the patient had a markedly narrowed orifice in the left upper lobe, as demonstrated by fiberoptic bronchoscopy. Chest radiographs of this lung field revealed no infiltrative shadows. These results suggest that some inhalative agent was involved in the pathogenesis of PAP in this case. In addition, significantly increased levels of KL-6 detected in both serum and bronchoalveolar lavage fluid were attributable to overproduction of KL-6 by Type II pneumocytes that had been stimulated or damaged by PAP.

Respiratory findings in workers employed in the brick-manufacturing industry

We studied 233 male workers employed in two brick-manufacturing plants and 149 matched control workers. The mean age of the brick workers was 35 years, with a mean duration of employment in this industry of 16 years. The prevalence of chronic respiratory symptoms as well as acute symptoms during the work shift were recorded. Lung function was measured on Monday during the work shift by recording maximum expiratory flow-volume (MEFV) curves, from which the forced vital capacity (FVC), the one-second forced expiratory volume (FEV1) and flow rates at 50% and the last 75% of the FVC (FEF50, FEF75) were measured. The results of periodic chest roentgenograms were reviewed. There was a significantly higher prevalence of chronic cough (31.8%), chronic phlegm (26.2%), and chest tightness (24.0%) in exposed workers, compared with control workers (20.1%; 18.1%; 0%) (P < 0.05). This increased symptom frequency was also documented among nonsmokers studied by age and by length of employment, suggesting a work-related effect. Among work shift-related symptoms, high prevalences were noted for upper respiratory tract symptoms (e.g., dry throat, eye irritation, throat irritation). The measured FVC and FEV1 were significantly lower than predicted for brick workers and suggested a restrictive pattern. The mean FVC (as a percent of predicted) was 78.1% and FEV1 was 88.1%. The FEF50 and FEF25 were not significantly decreased. A multiple regression analysis with age, exposure, and smoking as predictors and lung function parameters as response variables showed a significant effect between exposure and FVC. Significant chest roentgenographic abnormalities were not documented. These findings of a restrictive lung function pattern in brick workers with normal chest roentgenograms may suggest early interstitial disease. Additionally, a bronchitic component, as suggested by the respiratory symptoms, may also be present.

Leptospirosis associated with severe pulmonary haemorrhage in Far North Queensland

Pulmonary haemorrhage as a manifestation of leptospirosis is rarely diagnosed in developed countries. Five patients with proven leptospirosis associated with severe pulmonary haemorrhage presented to one hospital in Far North Queensland between January 1994 and June 1997. Four required admission to the intensive care unit and one patient died. Pulmonary haemorrhage is an uncommon but severe complication of leptospirosis and may be a source of diagnostic confusion in tropical areas of Australia.

Hand-arm vibration syndrome with proximal ulnar artery occlusion

The case of a man exposed during 25 years to vibration while maneuvering a heavy earth moving tractor is reported. The first clinical manifestation of hand-arm vibration syndrome was a bilateral Raynaud's phenomenon followed five years later by digital necrosis. The arteriography revealed a proximal and bilateral ulnar artery occlusion. Bilateral median nerve conduction abnormalities were also present. Vibration exposure level was much higher than the threshold level proposed by the European Commission. Laboratory examinations for vasculitis and other vascular diseases were all negative. The purpose of this report is to show that vibration can be responsible for proximal occlusion of a medium sized artery and severe neurovascular abnormalities which must be distinguished from the usual vasospastic Raynaud's phenomenon and the classical hypothenar hammer syndrome. An early and correct diagnosis is crucial because continued repetitive trauma can result in irreversible ischemic injury and loss of digits.

The validity of radiographic estimation of total lung capacity in patients with respiratory disease

STUDY OBJECTIVE

To evaluate the validity of a state-of-the-art computerized planimetry technique for estimation of total lung capacity (TLC) from chest radiographs, when applied to patients with clinical lung disease receiving routine chest radiographs.

DESIGN

Retrospective clinical survey.

SETTING

An occupational medicine diagnostic clinic.

PATIENTS

A convenience sample of 40 subjects with asbestos-related lung disease, 5 patients with nonasbestos-related restrictive defects, 15 subjects with occupational asthma, and 10 subjects with irritant tracheobronchitis.

RESULTS

Estimation of TLC using state-of-the-art computerized algorithms demonstrated limited agreement with conventional measures of TLC when applied to patients with occupational lung disease receiving routine chest radiographs. The most pronounced differences occurred in patients with asbestos-related lung disease and restrictive defects, where the radiographic method of measurement significantly overestimated helium dilution TLC by 986 mL (r=0.73, p<0.001) and 1,135 mL (r=0.82, p<0.05), respectively. Good inspiratory effort was associated with significantly increased radiographic TLC relative to helium dilution TLC; however, radiographic features did not fully account for the observed differences between radiographic and helium dilution techniques.

CONCLUSIONS

Our findings suggest that this planimetric technique should not be used as a substitute for conventional measures of TLC in clinic populations receiving routine radiographs. The large diagnostic group specific mean differences observed between radiographic and conventional measures of TLC also suggest that this method is of limited utility in clinical evaluation of occupational lung disease.

Asbestos-related x-ray changes in foundry workers

Michigan has a statewide mandatory occupational disease reporting system. As part of that system, reports are received from hospital, physicians, death certificates, the worker's compensation bureau, and company medical departments. Based on this reporting, the State of Michigan has a special emphasis program for the surveillance of silicosis, a known disease outcome among foundry workers. From 1985-1996, 115 cases reported to the State Surveillance System as silicosis, pneumoconiosis not specified, or pulmonary fibrosis were reclassified as having asbestos related x-ray changes after a B-reader interpretation of each case's chest x-ray. During this same period there were an additional 697 reports confirmed as silicosis and 6,724 cases reported to the surveillance system as asbestosis. Among the 115 reports reclassified as having asbestos-related x-ray changes without evidence of silicosis-related x-ray changes, 54 had worked in foundries. Only 7 (14.8%) of these individuals had their primary work in maintenance in the foundry; 40 (85.1%) had their primary foundry work in a production job; and for 10 individuals the occupation was not known. Asbestos has been used in foundries on pipe laggings, boiler coverings, as insulation in fan housings, in gloves, aprons and curtains, as insulation in cupolas, and in ladles and insulation in sand molds. Clinicians caring for foundry workers need to be aware that asbestos-related x-ray changes are not uncommon in this population and asbestos exposure should be considered as one of the carcinogens contributing to the known increased risk of lung cancer among foundry workers.

Interstitial lung disease more than 40 years after a 5 year occupational exposure to talc

A 62 yr old woman was initially diagnosed with sarcoidosis until a thoracoscopic biopsy revealed the presence of numerous birefringent particles in fibrotic areas of the centrilobular lung zones. These particles were examined by electron microscopy and X-ray spectrometry and characterized as impure talc. Further inquiry into her occupational history revealed that she had worked from the age of 14-18 yrs in a factory making rubber hoses, where she had had an intense exposure to talc. There was no evidence of silicosis or asbestosis, and other significant causes of interstitial lung disease were excluded. This case emphasizes the importance of a thorough occupational history, which may reveal a remote and forgotten exposure to a significant cause of interstitial lung disease. Although this presentation of talcosis is unusual, this case suggests that even a relatively short, but presumably intense exposure to talc more than 40 yrs previously may be a cause of progressive lung fibrosis.

Use of ultrasonography in monitoring work-related carpal tunnel syndrome: a case report

Carpal tunnel syndrome (CTS) is a syndrome whose diagnosis is well established. One cause could be occupational factors, while others have no relation to work or the work environment. We present in this article a case report regarding a worker affected by CTS, which is of interest concerning the sensitivity of ultrasonography and electroneurography, applied as diagnostic methods, related in our protocol to the variations in occupational exposures. The case reports an agricultural worker, whose tasks required repetitive and high frequency movements of the hand-arm. Diagnosis of CTS used ultrasonography and electroneurography techniques. In our opinion, the clinical evolution of CTS encompasses three "work-related" phases (preclinical phase; phase of nerve compression; phase of irreversible damage). Ultrasonography provides greater information about the evolution of CTS, as well as other cumulative trauma disorders, and is able to discern tendinitis of flexors causing a compression on the median nerve in the carpal tunnel.

Muscular hypertrophy of the left diaphragmatic crus: an unusual cause of a paraspinal "mass"

We present a case of marked muscular hypertrophy of the muscular portion of the diaphragm and of the diaphragmatic crura in a professional opera singer. In this case the right and left crus each measured 20 mm in maximum thickness. The left crus, by nature of its vertical orientation in the sagittal plane, produced marked deviation of the inferior left paraspinal line near the diaphragm mimicking a retrocrural or paraspinal mass on the posteroanterior chest radiograph. The correct diagnosis was made by computed tomography. Muscular hypertrophy of the diaphragmatic crura should be included in the differential diagnosis of retrocrural or paraspinal masses at the level of the diaphragm.

[Large aerobatic G-loads and degenerative-dystrophic changes of the spine in pilots: a new problem?]

Based on the analysis of available literature, a quantitative estimation of the role of chronic exposure to large aerobatic g-loads on modern aircraft in the risk of degenerative/dystrophic shifts in the spinal lumbar zone of flying personnel was attempted. In the opinion of the author, these g-loads increase the probability of spinal osteochondrosis in 1.5 to 1.75 times.

Long-term pulmonary and systemic toxicity following intravenous mercury injection

Long-term pulmonary and systemic toxicity following mercury intravenous injection has rarely been assessed. We present the results of a detailed investigation assessing pulmonary and systemic long-term toxic effects in a subject who had pulmonary and systemic mercury microembolism diagnosed more than 11 years previously. Radiographic examination showed the persistence of mercury microemboli in both lungs and elsewhere in the body. Lung function tests revealed a decreased diffusing capacity for carbon monoxide and PO2 probably indicative of microscopic inflammation of lung interstitium. Electroneuromyography showed signs of mild axonopathy in both legs. At semen analysis, a high proportion of motionless spermatozoa was present. Urinary excretion of mercury was high. Signs of interstitial lung impairment, peripheral axonopathy and asthenozoospermia in a subject who had mercury microembolism persisting for more than 11 years might be evidence of long-term mercury toxicity.

Pericardial effusion associated with asbestos exposure

The case history is presented of a 60 year old man who developed a pericardial effusion. Chest radiography showed pleural thickening and calcification. Pericardiotomy was performed and revealed nonspecific inflammatory lesions. Occupational exposure to asbestos and exclusion of other causes led to the diagnosis of benign asbestos pericardial effusion.

[Hamman-Rich syndrome in a goldsmith]

We report the case of a 54-year old goldsmith admitted because of dyspnea on exertion, persistent cough, and weakness under the suspicion of exogenous allergic alveolitis. He rapidly developed progressive lung fibrosis with exitus letalis 7 weeks after admission. Radiological examination (chest X-ray and HRCT) first showed ground glass opacties, and later rapid development of severe interstitial pattern with architectural distraction. The findings were similar to idiopathic lung fibrosis; however, the rare Hamman-Rich syndrome was confirmed by progressive course of the disease. Correlations between Hamman-Rich syndrome and idiopathic lung fibrosis are discussed.

Hypersensitivity pneumonitis due to inhalation of fungi-contaminated esparto dust in a plaster worker

Hypersensitivity pneumonitis or extrinsic allergic alveolitis can be defined as a lung disease caused by a wide group of antigens that reach the lung by inhalation of organic and/or inorganic dust of various sources. The esparto (Stipa Tenacissima and Ligeum Spartum) is an herbaceous of the grass family used in the production of ropes, canvas, sandals, mats, baskets, and so forth. It is also used in the construction industry for the production of paper paste. Inhalation of esparto dust has been reported as cause of hypersensitivity pneumonitis. The existence of precipitating antibodies against esparto extract has been proved. During the esparto fiber manufacturing process, esparto grass can be contaminated by moulds and thermophilic actinomycetes, which have been described as the causing antigens of hypersensitivity pneumonitis in plaster workers. We present a case of occupational hypersensitivity pneumonitis in a plaster worker. Clinical findings, precipitating antibodies, and evolution, after having removed him from his work, confirmed the diagnosis. In our case, Aspergillus species contaminating esparto are probably the antigens that caused the disease.

[Occupationally-induced degenerative discopathies in the area of the lumbar spine]

A case-control study comprising 188 male and 160 female cases from an orthopedic's cabin explained occupational risk factors for osteochondrosis, spondylosis, and spondylarthrosis of the lumbar vertebra. The controls (109 men, 130 women) steaming mainly from other physician's offices were free from musculoskeletal symptoms. Age-adjusted odds ratio (OR) were calculated for both sexes. In women elevated ORs were found for working in standing position (OR 2.2 CI 1.31-3.85), for repetitive work (OR 1.9 CI 1.17-3.36), for lifting heavy things up to 20 kg (OR 2.1 CI 1.24-3.67), for working as a secretary (OR 1.8 CI 1.16-3.0) or in a supermarket (OR 2.1 CI 1.05-4.56). Men showed elevated ORs for bending (OR 2.2 CI 1.27-4.08), vibrations of the upper limbs (OR 2.3 CI 1.12-5.02), whole-body-vibrations (OR 2.1 CI 1.14-4.11), working in the metal industry (OR 3.6 CI 1.88-6.89) or as motorists for more than ten years (OR 6.5 CI 1.54-27.99) and working in a humid or cold environment (OR 2.2 CI 1.30-3.72).