Q J Med 2002; 95: 185-186
© 2002 Association of Physicians
Correspondence |
Accidental occupational exposure to CNS-toxic substances in bank employees
Biochemical Research Center, Charité School of Medicine, Humboldt-University, Berlin, Germany
Sir,
Exposure to toxic substances in the workplace is a frequent cause of occupational disease.1 Apart from inhalative exposure, indigestion and percutaneous resorption may also cause signs of intoxication and reactions. We report two bank employees, aged 22 and 23 years, who presented with transient neurological symptoms caused by toxic substances. On physical examination, one still complained of increasing vertigo caused by eye movement, slight ataxia while the eyes were closed, and a sore throat. History revealed headache, vertigo and a general feeling of weakness and illness for two days. Analysis of their workplace (at ground level) did not reveal any toxic substances, but on further investigation, on the upper floors of the building the parquet flooring had been sealed for two days using a special sealing system (Lobadur PU 6020 Rapid). This included the following organic components: n-butyl acetate, light naphtha, 2-methoxy-1-methylacetate, 1,2,4-trimethylbenzene, propylbenzene, 1,3,5-trimethylbenzene and a mixture of 2,4- and 2,6-toluene diisocyanate. The workers in this area of the building had worn security suits according to the guidelines. However, elements of the sealing compound that evaporated were distributed by the air-conditioning system to the rooms in the ground floor. The two patients were asked about noticing a varnish smell prior to the symptoms, and they said that despite such a smell in the room, staff decided not to open the windows for security reasons. The employees continued to work until 5 pm, and the air was not free of aerosols until midday the next day. When the symptoms of vertigo began, and co-workers complained of headaches, the bank management decided to send employees home, and the two employees were admitted. In total, the patients were exposed to aerosols of organic solvents for about 12 h over 2 days. Apart from the transient neurological symptoms, no further signs were recorded. All blood parameters were within normal limits and no further complaints were noticed in the following weeks.
Inhalation is a frequent and very important mode of exposure to toxic substances at the place of employment. Usually, chronic low-dose exposure is the cause of occupational diseases, but accidental inhalative exposure to volatile substances that may lead to intoxication or toxic reactions also occurs frequently, and is often not diagnosed. Organic solvents and solvent mixtures are components of many household and industry products. Long-term occupational exposure to organic solvents, especially hexacarbons, even at low dosage, may cause persistent damage to the nervous system, liver, kidney and the bone marrow. Workers periodically exposed to solvents complain of a variety of symptoms such as numbness, loss of memory and concentration, psycho-organic syndromes, paraesthesiae2,3 and loss of strength in distal muscles caused by a reduction in numbers of acting motor units.4 On account of several reports on the chronic occupational intoxication of painters and other workers by aerosols of organic solvents, many protective measures such as suits, masks and inhalers were established in order to reduce the risk of occupational diseases. These precautions were taken by the painter who carried out the varnishing work in the upper floors of the building. Symptoms produced by acute high-dose inhalation of solvents can include euphoria, excitement, sedation, delusion, and visual and auditory hallucinations. These symptoms are reversible, lasting from 15 to 45 min, and reflect the cause of the abuse and addiction potential of organic solvents. Chronically abused, the acute symptoms are often followed by stupor, drowsiness, rhinitis, coughing, nausea or myalgias.5 However, symptoms of intoxication may also occur post-exposure after periods of many hours. The present long-distance low-dose exposure of nearly two work days shows that even if precautions are taken for the painters, solvents may be transported to other areas and cause symptoms in other workers.
In summary, the widespread use of organic aerosols and the increasing numbers of air-conditioning systems may lead to future cases, possibly in greater numbers. Physicians should be alert to the improper use of organic solvents, which may lead to intoxication in workers other than painters, and should ask about any such exposure in patients presenting with transient or permanent neurological symptoms.
References
1. Paustenbach DJ. Health risk assessment and the practice of industrial hygiene. Am Ind Hyg Assoc J1990; 51:339–51.[Medline]
2. Rosén I. Neurophysiological aspects of organic solvent toxicity. Acta Neurol Scand1984; 100:101–6.
3. Struwe G, Wenneberg A. Psychiatric and neurological symptoms in workers occupationally exposed to organic solvents: results of a differential epidemiological study. Acta Psychiatr Scand Suppl1983; 303:68–80.[Medline]
4. Lille F, Margules S, Mallet A, Deschamps D, Garnier R, Dally S. Evoked potentials in workers occupationally exposed to organic solvents. Electromyogr Clin Neurophysiol1993; 33:279–83.[Medline]
5. Norman, S, Miller, M.D, Mark, S, Gold, M.D. Organic solvent and aerosol abuse. Am Fam Physician1991; 44:183–9.[Medline]
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