Central pontine myelinolysis and medullary myelinolysis.

Central pontine myelinolysis (CPM) is a rare, acute, and uniformly fatal demyelinative process that involves the pons almost exclusively. Three cases diagnosed at autopsy illustrate the characteristic clinical course and pathologic features of CPM. A unique extrapontine location of a similar process is noted in the medulla of a 6-year-old girl. The term "medullary myelinolysis" is a descriptive designation for demyelination that occurs predominantly in this area. The clinical and pathologic features of CPM are reviewed in detail, together with a brief review of theories of metabolic, nutritional, vascular, and endogenous and exogenous toxic factors that act either singly or in concert in the cause and pathogenesis of CPM.