Spongy Degeneration of the Central Nervous System and Other Forms of Spongy Myelinopathy

Abstract

The hereditary infantile disease known as spongy degeneration of the central nervous system of the van Bogaert-Bertrand type belongs to a group of conditions characterized by a microvacuolar, spongy state affecting predominantly, but not exclusively, the white matter. Sponginess of the tissue, or status spongiosus, as revealed by the light microscope, is not a specific type of tissue alteration. Taken on its own merit, it is an arbitrary criterion for the classification of disease entities. However, the status spongiosus of spongy degeneration of the van Bogaert-Bertrand type was shown on electron microscopic examination to be the result of a specific alteration in the fine structure of myelin, consisting of accumulation of large pockets of fluid between the lamellae of the sheaths. This change needs to be distinguished from the splitting of lamellae without outpouching of the sheaths as a preparative artefact or with retrogressive changes in the sheaths. Intramyelinic fluid accumulation, or spongy myelinopathy, is shared by the otherwise heterogeneous diseases described in the present chapter.