Chronic relapsing polyneuritis. A light- and electron-microscopic study.

The clinico-pathologic findings in two patients with chronic relapsing polyneuritis are reported. The patients had several attacks of diffuse polyneuritis followed by partial recovery. The tendency to persisting disability increased following relapses and in the late stages there was a progressive motor deterioration suggesting a continuing activity of nerve damage. The biopsies of peripheral nerves, obtained in the advanced stages of the disease, showed severe loss of myelinated fibers and aspects of repeated demyelination and remyelination, with formation of onion bulb complexes. Completely demyelinated axons together with remyelinating fibers as well as remyelinated fibers invested by macrophages were seen at the same time. The clinical and pathological evidences suggest that in chronic relapsing polyneuritis, at least in the late stages of the disease, besides clinical relapses, there is a continuing activity of nerve damage. Thus, due to this ongoing activity of demyelination and remyelination, the elimination of the supernumerary Schwann cells does not take place satisfactorily and hypertrophic changes of the nerve fascicles are produced.