From clinical activities to didactics and research in occupational medicine.

BACKGROUND: The daily practice of Occupational Physicians in the mot industrialized countries suggests that the frequency of traditional occupational diseases is progressively lowering, their gravity is decreasing, and the etiological factors are changing. This trend should be quantitatively and qualitatively verified with ad hoc studies. The information is particularly relevant for Academic Institutions where medical students and residents in occupational medicine are trained. OBJECTIVES: To analyse the trends of clinical diagnoses and health surveillance activities conducted in the last 15 years by an Italian Institute of Occupational Health, and to gain information on the most relevant topics to be taught in academic program and to be addressed with future research. METHODS: Data sources were represented by the computerised registration of a) diagnostic activities and b) health surveillance programs, conducted by the Institute of Occupational Medicine of the University of Brescia, a highly industrialized area in Northern Italy. The observation period was from 1990 to 2005. The health surveillance programs regarded workers pulled from an iron foundry, a veterinary institute, a health departments for the assistance of elderly subjects, a nursery schools and a municipal department for road maintenance. RESULTS: Diagnostic activities were conducted on 9080 subjects, who had been referred for suspected occupational disease. The diagnosis of occupational disease was confirmed for 3759 cases. Multiple diseases were diagnosed in 1554 subjects, yielding the total number of 5721 occupational diseases. The most frequent diagnoses accounted for allergic skin disease (23.4%), followed by pneumoconiosis (20.4%), chronic obstructive pulmonary disease (15.9%), noise hearing loss (7.1%), musculoskeletal disorders (6.9%), respiratory allergies (6.9%), cancer (5.9%), miscellaneous (6.4%). When limited to the last quinquennium, the analysis showed a definite increase of muskuloskeltal disorders, cancer, and, although at a lesser extent, diseases due to psychosocial factors. The analysis of the health surveillance programs regarded 1207 workers, and showed that various non occupational diseases caused limitation to individual work fitness. The most frequent conditions were musculoskeletal disorders (65%) and skin diseases (14%). CONCLUSIONS: The results from these two investigations are important not only for the didactic program run by the Institute, but also because they indicate the most relevant topics to be addressed with future research, at least at a local level.

Changes over a workshift in aesthesiometric and vibrotactile perception thresholds of workers exposed to intermittent hand transmitted vibration from impact wrenches.

OBJECTIVES: To investigate the changes over a workshift in fingertip tactile perception thresholds in users of impact wrenches exposed to intermittent hand transmitted vibration. A further aim was to assess the relation between acute changes in tactile sensation, sensorineural disorders, and vibration dose. METHODS: The study populations consisted of 30 workers exposed to vibration (16 men and 14 women) and 25 control manual workers (10 men and 15 women). Sensorineural disorders in the fingers and hands were graded according to the staging system of the Stockholm workshop scale. Tactile function was tested by measuring aesthesiometric thresholds (two point discrimination and depth sense perception) and vibrotactile perception thresholds at 16, 31.5, and 125 Hz before and after a workshift. Temporary threshold shift was then calculated as the difference between threshold measures before and after the shift. The measurement and assessment of exposure to vibration were made according to the international standard ISO 5349. The vibration dose accumulated over a workshift (m2s-4h) was estimated for each user of impact wrenches. Daily exposure to vibration was also expressed in terms of eight hour energy equivalent frequency weighted acceleration ((ahw)eq(8) in ms-2 rms). RESULTS: After adjustment for age and alcohol consumption, vibrotactile perception thresholds before exposure were greater in the workers exposed to vibration than in the controls. No differences in aesthesiometric thresholds before the shift were found between the study groups. Sensorineural disorders were mild in the workers exposed to vibration and minor neurological abnormalities were detected at the physical examination. Owing to the intermittent use of impact wrenches, the estimated mean (ahw)eq(8) for the subjects exposed to vibration was low (1.3 ms-2 rms). A significant temporary threshold shift in vibration perception at all test frequencies was found in the workers exposed to vibration but not in the controls. A significant increase in depth sense perception thresholds was found in the men exposed to vibration. The temporary threshold shift in vibration perception at 125 Hz, and to a lesser extent at 16 and 31.5 Hz, was associated with the severity of sensorineural disorders. In the workers exposed to vibration the temporary threshold shift in vibration sense at all test frequencies was positively related to the estimated dose of vibration received over a workshift. No significant relation was found between aesthesiometric threshold changes and vibration dose. CONCLUSIONS: Intermittent exposure to hand transmitted vibration over a workshift can cause a deterioration of tactile perception in the fingers of users of impact wrenches. Acute tactile dysfunction was related to both the estimated dose of vibration and the severity of sensorineural symptoms. The temporary threshold shift in vibration perception suggested that fast adapting skin mechanoreceptors such as Pacinian and Meissner corpuscles were mainly involved in the acute sensory impairment to the fingertips of the workers exposed to vibration. Changes in tactile perception can occur in workers with daily exposure to vibration that is considered to be associated with a minimal risk of adverse health effects induced by vibration.

An "occupational miliary" due to nitrous gases.

The authors report the case of a patient suffering from chemical pneumonia due to nitrous gases of occupational origin which was mistakenly taken for military tuberculosis. Anamnestic, clinical and anatomopathological aspects of this disease, which successively analysed, often make the diagnosis difficult due to their complexity and lack of specificity.

Neurobehavioral effects of manganese in workers from a ferroalloy plant after temporary cessation of exposure.

OBJECTIVES: The goal of this study was to assess long-term neurobehavioral effects associated with low airborne concentrations of manganese in a ferroalloy plant. METHODS: During a period of forced cessation of work (1 to 42 d) neurobehavioral performance on tests of simple reaction time, finger tapping, digit span, additions, symbol digit, and shapes comparison was evaluated for 58 workers exposed from 1 to 28 (mean 13, SD 7) years to manganese. Airborne manganese concentrations in total dust had been reduced in the last 10 years from 70-159 micrograms x m-3 (geometric means in different areas) to 27-270 micrograms x m-3. For each worker, manganese concentrations in blood and urine were measured, and a cumulative exposure index was also calculated. RESULTS: Blood manganese and urinary manganese ranged from 4 to 18 micrograms x 1-1 (0.07 to 0.03 mumol x 1-1) and from 0.7 to 7 micrograms x 1-1 (0.01 to 0.13 mumol x 1-1) respectively. Significant relationships were found between the blood manganese and urinary manganese levels and between these biological measures and the cumulative exposure index. Correlations were also found between the blood manganese level, the urinary manganese level, and the cumulative exposure index and the following tests: finger tapping, symbol digit, digit span, and additions. The correlation coefficients increased as the latency time after the cessation of exposure and work seniority increased. CONCLUSIONS: The results support the hypothesis that the neurobehavioral effects observed at exposure levels well below current occupational standards are related to manganese body burden, which is better reflected by the blood manganese level after the cessation of exposure.