TOLUENE/XYLENE
Repeated exposure to toluene has caused encephalopathy in humans, with changes in gait and balance because of cerebellar changes, and cognitive dysfunction.[1] Toluene toxicity is similar to xylene 1, which causes irritation of skin, eyes and respiratory system and brain effects like reduced coordination, slurred speech, altered balance, tremors, labile emotions.1 Toluene is rapidly absorbed through the lungs and deposited in brain and fatty tissue. [2] High or repeated exposure can cause confusion, reduced coordination, euphoria during exposure, and in some cases personality changes resembling schizophrenia. 2, [3] Toluene causes dysfunction of the peripheral and autonomic nervous system, headache, weakness (lassitude) and persistent impaired mental function, including visual intelligence, verbal intelligence, memory, sensory and vestibular function.[4] It can alter brain and other cell membranes, and causes chronic neurotransmitters.[5] Chronic exposures can impair cognitive performance, hearing and visual activity, neuromuscular function, odor discrimination, psychological stability, and neurasthenia2 (fatigue). Other effects of chronic exposure include tremor, unsteadiness, emotional lability, insomnia, alcohol intolerance, cerebellar ataxia (abnormal gait) and optic nerve dysfunction.[6]An epidemiologic study of toluene exposed workers showed symptoms of chronic fatigue (60%) impaired concentration (40%), irritability (37%), headaches (30%) and paresthesia (53%-numbness/tingling).[7] Other studies show testing impairments in toluene-exposed persons: optic neuropathy, impaired equilibrium, auditory evoked potentials, and a wide variety of neurocognitive testing impairments.7,[8]
Chronic effects after exposure to toluene and xylene in humans include fatigue, headache, alcohol intolerance, irritability, reduced memory and concentration, and mood disturbance which persisted after exposure, resulting in a diagnosis of toxic encephalopathy.[9] Workers exposed to a toluene and xylene mixture developed headaches, reduced memory and concentration and persistent brain dysfunction on neurocognitive testing a year after the end of exposure.[10]
[1] Clinical Toxicity of Commercial Products, edited by RE Gosselin etal. Williams and Wilkins, Baltimore, 1984.
[2] Hamilton and Hardy’s Industrial Toxicolog, edited by AJ Finkel, John Wright, Boston, 1983.
[3]Neurotoxicity of Industrial and Commercial Chemicals, edited by JL O’Donoghue, CRC Press, Boca Raton, Florida, 1985.
[4] Environmental Health Criteria 52: Toluene, World Health Organization, Geneva, 1985.
[5] Toxicological Profile for Toluene, August 1988, U.S. Department of Health and Human Services, Agency for Toxic Substances and Disease Registry.
[6] Neurotoxins in Clinical Practice, edited by CG Goetz M.D. Medical and Scientific Books, Spectrum Publishers, 1985.
[7] Neurotoxicology: A clinical sourcebook, by PG Bernard M.D. Lexis Publishing, Charlottesville, VA. 1998.
[8] Chemical Brain Injury, by KH Kilburn M.D., Van Nostrand Reinhold, NY, 1998.
[9]NK Jorgensen etal., “Poisoning with organic solvents in a group of female serigraphic workers in the plastic industry”, Ugeskr Laeg 146:1391, 1984.
[10] B. Melgaard and P Arlien-Soborg, “Occupational brain damage”, Ugeskr Laeg 140:1650, 1978.