[Neuropathy by n-hexanes: a generalized disorder of the intermediate filaments]

Chronic inhalation of glues containing n-hexanes produces neurofilament (NF) accumulation which induces sensory-motor polyneuropathy. In vitro assays have shown this toxic substance causes intermediate filaments (IF) aggregation in non-neuronal cells.

To describe intermediate filament changes in human pathology due to n-hexanes.

Sural nerve and skin biopsy samples from 2 patients who suffered from a severe sensory-motor polyneuropathy after prolonged inhalation of glue containing n-hexane were examined with electron microscopy and vimentin and phosphorylated NF immunocytochemistry.

Abnormal accumulations of NF and NF-immunoreactive products occurred in nerve fibers and increased numbers of fibrils were observed in endoneurial endothelial cells of the sural nerve. In addition, abnormal vimentin-immunoreactive deposition was seen in fibroblasts and capillaries of the skin. The present results suggest that high doses of n-hexane cause a diffuse IF disorder in a similar form as occurs in giant axonal neuropathy.

IF aggregation can occur in non-neuronal cells in humans, as has been previously proved in in vitro experiments. The presence of IF accumulations in Schwann cells, as seen in the ultrastructural examination, together with the electrophysiological findings showing an early decrease of sensory and motor nerve conduction velocities, suggests the existence of a primary myelinic disorder associated with axonal damage.