Localization of the pathological process in Miller Fisher syndrome.

A 64 year old woman died at the third attack of MFS. Histological examination demonstrated segmental demyelination and axonal swelling of the peripheral nerves studied, oculomotor included. In the C.N.S. only mild chromatolytic changes and rare pyknosis of the nerve cells in the midbrain were found without signs of primary inflammation. We reviewed the findings in all the 4 anatomoclinical cases of MFS and in 2 cases of GBS with ophthalmoplegia or ataxia. With one exception, they appear to be concordant with those of our case. As the histological examination showed CNS involvement consequent upon peripheral nerve impairment, we are bound to change our opinion on the nosological position of MFS. Any small CT enhancements in the brain in MFS may be due, as in some cases of demyelinating polyneuropathy, to focal rupture of the blood-brain barrier.