The pathology of amiodarone neurotoxicity. II. Peripheral neuropathy in man.

Sural nerve changes are described in 2 cases of amiodarone neuropathy. Clinically, 1 patient developed a sensorimotor neuropathy, whereas in the other it was predominantly motor. Examination of sural nerves showed demyelination with only mild axonal loss. Cytoplasmic changes developed in Schwann cells of myelinated and unmyelinated axons, and involved loss of most recognizable organelles. These changes were associated with, and possibly preceded, myelin sheath breakdown. Inclusions, mainly of a lamellated type, were found in all cell types in the nerves. These inclusions, known to be lysosomal in origin, are a characteristic finding in amiodarone-induced neuropathy. The pathogenesis of the neuropathy is discussed, with particular reference to the findings in a parallel experimental study.