A review of the causes of central pontine myelinosis: yet another apoptotic illness?

One of the well recognized stimuli for central pontine myelinosis (CPM) is the rapid correction of chronic hyponatraemia. Conventionally this has been perceived to lead to pontine glial cell swelling through osmosis and eventually to cell death. However, although a purely osmotic argument has been central to any patho-physiological understanding of CPM, there are deficiencies in this approach that do not account for why certain individuals develop CPM with relatively mild osmotic insults. Here we review the varying aetiologies of CPM and propose a novel hypothesis for CPM causation by suggesting that individuals predisposed to CPM have inadequate energy provision as well as other factors that result in a pro-apoptotic drive, which renders them susceptible to brain injury from diverse causes. In CPM, the precipitant of brain injury appears to be osmotic stress. Furthermore, this model suggests a number of therapeutic interventions that may prevent or at least mitigate the consequences of CPM.