Temporal evolution of the trident and piglet signs of osmotic demyelination syndrome.

Central pontine myelinolysis (CPM) is a potentially-devastating complication of rapid osmolar shifts, classically attributed to overlyaggressive correction of chronic hyponatremia. Magnetic resonance imaging (MRI) allowed earlier diagnosis of CPM, but most importantly, it has revealed that the odds of good functional recovery are surprisingly high. A trident shaped pontine lesion is a typical finding in CPM (the trident sign). The "piglet sign" is a much less well-known radiologic finding in CPM. Due to the rarity of CPM, very little has been published on the evolution of these MRI findings. We present a case of CPM in an alcoholic young man, and describe the temporal evolution of both the trident and piglet signs on MRI in CPM.