Chronic Solvent Encephalopathy in a Printing Unit for Flexible Packaging

Abstract

The solvents are a large group of chemicals which are used industrially in the production of paints, glues, coatings, degreasing agents, dyes, polymers, pharmaceuticals and printing inks. They have three characteristics in common, namely they are volatile liquids at normal temperature, they are strongly lipophilic and most of them, if the dose is sufficiently high, affect the functioning of the central nervous system. Exposure to organic solvents can occur by inhalation, ingestion or absorption through the skin, but inhalation is usually the main route of entry. The health impact of workplace solvent exposure remains an issue of substantial interest and concern to occupational health professionals. In fact, there is a growing recognition that organic solvents are neurotoxic to the nervous system and its neuropsychological functions. For an agent to be neurotoxic, it must produce an adverse change in the structure and function of the nervous system following exposure to agents such as solvents. It is generally accepted that workers exposed to solvents for a long time may develop a Chronic toxic encephalopathy (CTE). The clinical picture of CTE is dominated by vague and non specific symptoms such as irritability, headache, sleep disturbances, concentrations problems and impaired memory. In 1985, a WHO Working Group presented diagnostic criteria and a classification for solvent-induced chronic toxic encephalopathy (CTE). In the same year, the “Workshop on neurobehavioral effects of solvents” in Raleigh, N.C., USA introduced a somewhat different classification for CTE. The objective of a systematic review of criteria for solvent-induced chronic toxic encephalopathy, was to study the diagnostic procedures that are used to establish the diagnosis of CTE, and the extent to which the diagnostic criteria and classification of the WHO, and the classification of the Raleigh Working Group, are applied. Thus a systematic search of studies on CTE was performed, and the diagnostic criteria and use of the WHO and Raleigh classifications were listed. They retrieved 30 original articles published in English from 1985 to 1998, in which CTE was diagnosed. Only two articles did not report the duration of solvent exposure. The type of solvent(s) involved was described in detail in four articles, poorly in 17 articles, and not at all in nine articles. Tests of general intelligence were used in 19 articles, and tests of both attention and mental flexibility and of learning and memory were used in 18 articles. Exclusion, by interview, of potentially confounding conditions, such as somatic diseases with central nervous effects and psychiatric diseases, was reported in 21 and 16 articles, respectively. In only six of the