Trichloroethylene toxicity

Toxic neuropathies associated with pharmaceutic and industrial agents

Neuropathies associated with industrial, environmental, and pharmacologic toxicants are uncommon. Nevertheless, it is important to consider toxic etiologies in the differential diagnosis of neuropathies, because they are among the most treatable forms of peripheral nervous system dysfunction. The purpose of this article is to discuss the clinical investigation of a suspected toxic neuropathy, to review some of the more common or representative neurotoxicants, and to identify the methods for establishing causation.

Evaluation of blink reflex results obtained from workers previously diagnosed with solvent-induced toxic encephalopathy

We reviewed blink reflexes recorded from 51 railroad workers with long-term occupational exposure to solvents who were diagnosed by others with solvent-induced toxic encephalopathy. No worker fulfilled conventional clinical criteria for dementia or trigeminal mononeuropathy. All workers had normal R1 and R2 blink reflex latencies. R1 latencies correlated significantly with several nerve conduction measures, including F wave latencies, suggesting that some intersubject variability reflected intrinsic conduction properties, not isolated brain-stem function. Although normal, the workers' R1 latencies were significantly prolonged compared with historical control groups, including gender-matched control subjects of similar mean age (11.2 ms vs 9.9 ms; P < 0.0001). Stepwise multiple regression models demonstrated significant associations of R1 latency with age and use of CNS-active prescription medications (P = 0.003), but duration of occupational solvent exposure did not enter into the models. Paradoxically, workers using CNS-active medications had significantly shorter R1 latencies compared with workers not using such medications (10.9 vs 11.7 ms; P = 0.01). Job title, another potential surrogate measure of exposure, was not significantly related to reflex latencies. The geographical site of predominant solvent exposure did influence R1 latency, and workers from one site had longer exposure duration and longer R1 latencies than remaining workers. However, an interaction between age and exposure duration (r = 0.39; P = 0.003) confounded interpretation of this observation. Disability or work status, mental status findings, or classification of encephalopathy did not influence blink reflex latencies. The overall results do not support, but do not entirely exclude, a possible relationship between subclinical blink reflex abnormalities and occupational exposure to solvents. Nevertheless, it is clear from these results that the small group differences in R1 latency between exposed workers and control subjects are of no diagnostic importance and of uncertain physiologic importance, and they may reflect unrecognized confounders and technical factors.

A sclerodermatous syndrome with unusual features following prolonged occupational exposure to organic solvents

We describe a sclerodermatous syndrome in a middle-aged man who had worked with a wide variety of organic solvents over a prolonged period. Associated changes included cold sensitivity, a restrictive lung defect, peripheral neuropathy, oesophageal dysfunction, labile hypertension and a monoclonal paraproteinaemia. This unique syndrome is discussed in relation to other disorders associated with exposure to organic solvents.

Environmentally-induced systemic sclerosis-like illness

Interaction of the host immune system with certain substances found in the environment will, in the presence of other unknown factors such as genetic susceptibility, lead to aberrant immune responses manifested as disease. In most of the conditions discussed above, simple removal from exposure to the offending agent does not lead to resolution. This suggests that an ongoing response has been triggered which cannot immediately be turned off, perhaps due to continued presence of the substance such as in human adjuvant disease where paraffin or silicone has been found in lymphoid tissue. Scleroderma remains a disease of uncertain cause for which our present treatment is inadequate. Illnesses presented in this chapter resemble the natural form of the disease in many ways and may provide useful insight into its pathogenesis. In the short term, recognition of exposure to environmental hazards which appear to pose risk will prevent additional cases of disabling illness. Study of chemically induced forms of scleroderma may, in the future, allow us to predict potential toxicity of chemically similar compounds. If we could learn how they trigger disease, researchers might be able to apply the information to understanding the pathogenesis of naturally-occurring scleroderma.

Generalized eruption with severe liver dysfunction associated with occupational exposure to trichloroethylene

Generalized dermatitis due to trichloroethylene is rare. A 21-year-old printer developed exfoliative dermatitis with mucous membrane involvement, fever and liver dysfunction after a 2-week occupational exposure to trichloroethylene. Positive patch-test reactions to trichloroethylene and to one of its metabolites, trichloroethanol, were observed. This dermatitis is considered to be mediated by a delayed-type hypersensitivity mechanism.

The role of skin absorption as a route of exposure for volatile organic compounds (VOCs) in drinking water

Assessments of drinking water safety rely on the assumption that ingestion represents the principal route of exposure. A review of the experimental literature revealed that skin penetration rates for solvents are remarkably high, and that the stratum corneum is a less effective barrier to penetration than traditionally assumed. Based on published skin absorption rates, we used Fick's law (Jos = Kop delta Cos) to determine permeability constants for selected compounds. We then calculated dose per kilogram for nine different exposure situations and compared this to the oral dose per kilogram. We found that skin absorption contributed from 29-91 per cent of the total dose, averaging 64 per cent. Dose per kilogram body weight ranged from .0002 mg/kg-.18 mg/kg, with an average of .03 mg/kg. In weak aqueous solutions, flux of the solute is directly proportional to concentration. Laboratory approaches differ markedly from environmental exposures and can underestimate absorption. We conclude that skin absorption of contaminants in drinking water has been underestimated and that ingestion may not constitute the sole or even primary route of exposure.

Sentinel Health Events (occupational): a basis for physician recognition and public health surveillance

A Sentinel Health Event (SHE) is a preventable disease, disability, or untimely death whose occurrence serves as a warning signal that the quality of preventive and/or therapeutic medical care may need to be improved. A SHE (Occupational) is a disease, disability, or untimely death which is occupationally related and whose occurrence may: 1) provide the impetus for epidemiologic or industrial hygiene studies; or 2) serve as a warning signal that materials substitution, engineering control, personal protection, or medical care may be required. The present SHE(O) list encompasses 50 disease conditions that are linked to the workplace. Only those conditions are included for which objective documentation of an associated agent, industry, and occupation exists in the scientific literature. The list will serve as a framework for developing a national system for occupational health surveillance that may be applied at the state and local level, and as a guide for practicing physicians caring for patients with occupational illnesses. We expect to update the list periodically to accommodate new occupational disease events which meet the criteria for inclusion.

A new syndrome with pigmentation, scleroderma, gynaecomastia, Raynaud's phenomenon and peripheral neuropathy

A middle-aged man developed impotence, gynaecomastia, peripheral neuropathy, pigmentation lymphadenopathy, scleroderma, malabsorption and Raynaud's phenomenon following prolonged exposure to trichlorethylene. Somes, but not all, of these features have previously been reported in vinyl chloride disease, and trichlorethylene is related chemically to vinyl chloride. Seven patients with a similar but not identical syndrome have been described in Japan and U.S.A., apparently unrelated to exposure to industrial toxins.