What is the role of PERC in the etiology of toxic neuropathy?

Updated: Dec 06, 2017
  • Author: Jonathan S Rutchik, MD, MPH, FACOEM; Chief Editor: Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS  more...
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Answer

PERC is an agent used in the dry-cleaning industry. Its various other uses are listed in Table 3. Peripheral neuropathy is a clinical diagnosis that is listed as secondary to chronic PERC exposure by Feldman. [38, 39] Neither article refers to specific study results. Spencer and Schaumberg list neuropathy with a question mark as an effect of tetrachloroethylene (ie, perchloroethylene) toxicity. This article refers to 2 articles by Antti-Poika and Juntunen et al that reported sensory trigeminal (fifth cranial nerve) defects in those exposed to mixed solvents. A 1978 National Institute for Occupational Safety and Health (NIOSH) publication on PERC remarked that "various disturbances of the peripheral nervous system such as tremors and numbness have also been associated with exposure to tetrachloroethylene."

Juntunen et al studied 87 patients from Finland diagnosed as having chronic intoxication caused by exposure to a mixture of solvents or to TCE and PERC between 1970 and 1974. Of these, 14 had been exposed to TCE or PERC alone, 53 to solvent mixtures, and 13 to all of them. Disturbances of cutaneous sensation and the sense of vibration were encountered frequently as clinical signs. [40]

The Antti-Poika article of the same year (1982) discussed the EMG findings of this same group. Electroneuromyography ([ENMG], including NCV and EMG) revealed 64 patients with signs positive for PNS disease and 34 patients with subjective symptoms. Signs of polyneuropathy were reported in 13 subjects. In the discussion, the author remarked that the number of patients with clinical polyneuropathy was so small that a trend could not be evaluated definitively. [41]

A publication the following year (1983) by Seppalainen and Antti-Poika categorized the specific ENMG findings of each of the 3 groups in the previously mentioned 2 studies. Of 18 patients in the group exposed to either TCE or PERC alone, 9 (50%) were deemed to have neuropathy on the first ENMG examination. On the second ENMG, 15 of 21 (71%) patients had this diagnosis. For those exposed to TCE or PERC or a mixture, 10 of 11 (91%) patients and 11 of 13 (85%) patients had this diagnosis, as opposed to 26 of 44 (59%) and then 38 of 53 (72%) of those exposed only to a mixture excluding chlorinated hydrocarbons (ie, TCE or PERC). The authors concluded that those patients with exposure to a mixture of solvents and to TCE or PERC tended to have neuropathic findings more often than patients exposed to either TCE or PERC alone or to a solvent mixture that did not include TCE or PERC. Findings on ENMG in these patients suggested axonal changes rather than segmental demyelination. [42]

One toxicology text remarked that neuropathy may present following solvent exposures because the solvent (ie, PERC) often is mixed with amines, epoxides, and esters to protect it from moisture and light. Some of these compounds are known to cause neuropathy. Two European articles report PERC as being associated with neuropathy. In 1989, Herruzo-Perez et al described one case in which the authors suspected that a sensitive painful polyneuropathy probably was caused by poisoning with PERC. [43] In 1989, Muller et al found slight derangements in neural functions in 130 dry-cleaning workers with long-term exposure to PERC during a 5-year follow-up study.

Baker reported in a review from 1994 that recent studies suggested that mild subclinical disruption of PNS function does occur in workers exposed to solvent mixtures. [44] In 1988, Orbaek et al studied patients with long-term exposures to organic solvents and found evidence of PNS dysfunction and slowing of the median nerve that was more pronounced in follow-up testing 22-72 months later. Slowing in the peroneal nerve was observed only at the follow-up NCV examination. Sensory conduction studies showed substantially reduced amplitudes in median and sural nerves with a prolongation of the distal latency in comparison with a control group; sensory conduction velocity in the median nerve also was slowed in the follow-up examination. [45]

Whether this and other studies of mixed organic solvent exposures suggesting neuropathy with various neurophysiological tests can implicate PERC is not clear, since PERC, its metabolites, or chemicals of similar structure may or may not have been a component of the solvent mixture. Maizlish et al refer to chlorinated aliphatic and chlorinated hydrocarbon solvents as components of paint vehicles and glues to which their subject population was exposed [46] ; other authors do not specify the composition of the substances to which their subjects were exposed.


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