- Email: [email protected]
Polyneuropathy from MBK
The chemical environment
218
the Finsen Institute in Copenhagen during the IO months ending in July 1974, 23 (2.07%) gave positive reactions to ED. The sensitizing agent in 17 cases was Mycolog cream, in which ED is used as a stabilizer. In three cases, cross-reaction was found to EDTA, which because of its widespread use was suspected of being the primary sensitizer. Other crossreactions detected were to promethazine hydrochloride and to diethylenetriamine, but not to triethylenetetramine. Over the same period, the 1111 patients gave positive reactions to neomycin in 86 cases, nickel in 75, dichromate in 46. balsams in 38, p-phenylenediamine in 36, rubber in 27 and parabens in five. ED thus took seventh place as a contact sensitizer in Denmark. a position not markedly different from that in the United States. However, the incidence of diagnosed reactions to this and other allergens was much lower in Danish patients than in the New York study, and the ranking of other leading sensitizers was also different. 3007. Polyneuropathy from MBK Allen, N., Mendell, J. R., Billmaier, D. J., Fontaine, R. E. & O’Neill, J. (1975). Toxic polyneuropathy due to methyl n-butyl ketone. An industrial outbreak. Arch
Neurof.
32, 209.
An epidemic of polyneuropathy which occurred in 1973 at an Ohio plant producing plastics-coated and colour-printed fabrics was linked to methyl n-butyl ketone (MBK) exposure (Cited in F.C.?: 1975, 13, 403) and animal studies subsequently confirmed the aetiological role of MBK (ibid 1976, 14. 157). Further details of the outbreak have now been presented. Of 1157 employees at the factory who were screened by electrodiagnostic examinations, 86 were identified as having a toxic polyneuropathy. Eleven of these cases were classified as moderate to severe, 38 as mild and 37 as minimal in intensity. Sensory signs predominated in the mildly affected men, and the sensory effects were accompanied by motor involvement in the more severe cases. In those classified as minimally involved, there were no objective neurological findings but abnormalities of muscle and nerve conduction were apparent. Distribution of such abnormalities and of muscle weakness was predominantly distal’; the weakness most commonly affected the intrinsic muscles of the hands and feet and the long extensors or flexors of the digits. Sensory loss was usually limited to the feet or fingers, and involved approximately equal loss of light touch, fast or pricking pain and temperature discrimination, and occasionally also of vibration sense. Reflex loss was minimal, being generally coniined to the disappearance of ankle and finger jerks. Initial symptoms were frequently an intermittent tingling paraesthesia of hands or feet, or a slowly developing weakness of these extremities leading to a slapping gait or to difficulty in coping with pincer movements or in grasping heavy objects. Weight loss was apparent in severe cases. Haematological examination revealed a reduction in mean erythrocyte acetylcholinesterase activity and an increase in mean plasma butyrocholinesterase activity, but these changes were unrelated to the severity of neuropathy.
In experimental studies, chickens exposed to MBK were found to show an increase in butyrocholinesterase activity. The epidemic afflicted printing work:rs, particularly machine operators, their helpers and pan washers, and was correlated with the number of hours worked each week. Workers in a base-coating section were also affected. The first case appeared in December 1972, 4 months after MBK had been substituted for methyl isobutyl ketone in a solvent mixture with methyl ethyl ketone (MEK). One man was affected after only 5 wk of exposure. Average levels of 36ppm MBK and 516ppm MEK were detected behind the printing machines. Workers in another plant exposed only to MEK showed no toxic neuropathy, but two cases were identified among workers elsewhere who were exposed to MBK alone. HOWever, although MEK alone was not found to induce neuropathy in animals, combinations of MEK and MBK had a markedly synergistic effect. MEK was also found to produce haematological changes in animals similar to those in the affected men. Discontinuation of the use of MBK in the Ohio plant prevented the occurrence o[ further cases, and improvement followed in all severely affected men and in the majority of those only mildly or minimally affected. Animal studies have since suggested that the threshold limit value for MBK should be set at 5 ppm, rather than at lOOppm, as is now the case. 3008. Health hazards of toluene diiwcyanate dustry
in in-
Adams, W. G. F. (1975). Long-term effects on the health of men engaged in the manufacture of tolylene di-isocyanate. Br. J. ind. Mrd. 32, 72. Sensitization resulting in difficulty in breathing and pain in the chest is an established phenomenon in workers exposed to toluene diisocyanate (tolylene diisocyanate; TDI) during the manufacture of polyurethane plastics (Cifed in F.C.T 1971. 9, 280). A 9-yr prospective study of workers manufacturing TDI involved an assessment of symptoms and lung function in men who reported no respiratory symptoms, and an assessment of the long-term effects of TDI on men whose development of respiratory disturbance led to their removal from the manufacturing plant. Among the men removed from further contact with TDI because of their respiratory symptoms, the proportion of the work force becoming symptomatic during their first year was 14.8%. The incidence of removals during the second and subsequent years ranged from 0.7 to 3.5% of the force working in any given year. Of the healthy men on the plant, none showed any symptoms significantly different from those in a control group apart from a tendency to wheeze, which was more frequent among the controls. In men who continued to work on the plant, TDI exposure had no significant effect on the values for forced expiratory volume (FEV,) and forced ventilatory capacity (FVC) in lung-function tests, compared with the measurement in an unexposed control group. However, among the symptomatic men removed from further exposure to TDI, breathlessness and wheezing were persistent and were commoner than in controls:
218
the Finsen Institute in Copenhagen during the IO months ending in July 1974, 23 (2.07%) gave positive reactions to ED. The sensitizing agent in 17 cases was Mycolog cream, in which ED is used as a stabilizer. In three cases, cross-reaction was found to EDTA, which because of its widespread use was suspected of being the primary sensitizer. Other crossreactions detected were to promethazine hydrochloride and to diethylenetriamine, but not to triethylenetetramine. Over the same period, the 1111 patients gave positive reactions to neomycin in 86 cases, nickel in 75, dichromate in 46. balsams in 38, p-phenylenediamine in 36, rubber in 27 and parabens in five. ED thus took seventh place as a contact sensitizer in Denmark. a position not markedly different from that in the United States. However, the incidence of diagnosed reactions to this and other allergens was much lower in Danish patients than in the New York study, and the ranking of other leading sensitizers was also different. 3007. Polyneuropathy from MBK Allen, N., Mendell, J. R., Billmaier, D. J., Fontaine, R. E. & O’Neill, J. (1975). Toxic polyneuropathy due to methyl n-butyl ketone. An industrial outbreak. Arch
Neurof.
32, 209.
An epidemic of polyneuropathy which occurred in 1973 at an Ohio plant producing plastics-coated and colour-printed fabrics was linked to methyl n-butyl ketone (MBK) exposure (Cited in F.C.?: 1975, 13, 403) and animal studies subsequently confirmed the aetiological role of MBK (ibid 1976, 14. 157). Further details of the outbreak have now been presented. Of 1157 employees at the factory who were screened by electrodiagnostic examinations, 86 were identified as having a toxic polyneuropathy. Eleven of these cases were classified as moderate to severe, 38 as mild and 37 as minimal in intensity. Sensory signs predominated in the mildly affected men, and the sensory effects were accompanied by motor involvement in the more severe cases. In those classified as minimally involved, there were no objective neurological findings but abnormalities of muscle and nerve conduction were apparent. Distribution of such abnormalities and of muscle weakness was predominantly distal’; the weakness most commonly affected the intrinsic muscles of the hands and feet and the long extensors or flexors of the digits. Sensory loss was usually limited to the feet or fingers, and involved approximately equal loss of light touch, fast or pricking pain and temperature discrimination, and occasionally also of vibration sense. Reflex loss was minimal, being generally coniined to the disappearance of ankle and finger jerks. Initial symptoms were frequently an intermittent tingling paraesthesia of hands or feet, or a slowly developing weakness of these extremities leading to a slapping gait or to difficulty in coping with pincer movements or in grasping heavy objects. Weight loss was apparent in severe cases. Haematological examination revealed a reduction in mean erythrocyte acetylcholinesterase activity and an increase in mean plasma butyrocholinesterase activity, but these changes were unrelated to the severity of neuropathy.
In experimental studies, chickens exposed to MBK were found to show an increase in butyrocholinesterase activity. The epidemic afflicted printing work:rs, particularly machine operators, their helpers and pan washers, and was correlated with the number of hours worked each week. Workers in a base-coating section were also affected. The first case appeared in December 1972, 4 months after MBK had been substituted for methyl isobutyl ketone in a solvent mixture with methyl ethyl ketone (MEK). One man was affected after only 5 wk of exposure. Average levels of 36ppm MBK and 516ppm MEK were detected behind the printing machines. Workers in another plant exposed only to MEK showed no toxic neuropathy, but two cases were identified among workers elsewhere who were exposed to MBK alone. HOWever, although MEK alone was not found to induce neuropathy in animals, combinations of MEK and MBK had a markedly synergistic effect. MEK was also found to produce haematological changes in animals similar to those in the affected men. Discontinuation of the use of MBK in the Ohio plant prevented the occurrence o[ further cases, and improvement followed in all severely affected men and in the majority of those only mildly or minimally affected. Animal studies have since suggested that the threshold limit value for MBK should be set at 5 ppm, rather than at lOOppm, as is now the case. 3008. Health hazards of toluene diiwcyanate dustry
in in-
Adams, W. G. F. (1975). Long-term effects on the health of men engaged in the manufacture of tolylene di-isocyanate. Br. J. ind. Mrd. 32, 72. Sensitization resulting in difficulty in breathing and pain in the chest is an established phenomenon in workers exposed to toluene diisocyanate (tolylene diisocyanate; TDI) during the manufacture of polyurethane plastics (Cifed in F.C.T 1971. 9, 280). A 9-yr prospective study of workers manufacturing TDI involved an assessment of symptoms and lung function in men who reported no respiratory symptoms, and an assessment of the long-term effects of TDI on men whose development of respiratory disturbance led to their removal from the manufacturing plant. Among the men removed from further contact with TDI because of their respiratory symptoms, the proportion of the work force becoming symptomatic during their first year was 14.8%. The incidence of removals during the second and subsequent years ranged from 0.7 to 3.5% of the force working in any given year. Of the healthy men on the plant, none showed any symptoms significantly different from those in a control group apart from a tendency to wheeze, which was more frequent among the controls. In men who continued to work on the plant, TDI exposure had no significant effect on the values for forced expiratory volume (FEV,) and forced ventilatory capacity (FVC) in lung-function tests, compared with the measurement in an unexposed control group. However, among the symptomatic men removed from further exposure to TDI, breathlessness and wheezing were persistent and were commoner than in controls: