A case of chronic asymptomatic central pontine myelinolysis with histological evidence of remyelination

Abstract

Central pontine myelinolysis (CPM) is a neurological demyelinating disease of the pons. Although usually associated with rapid correction of hyponatremia, CPM may occur despite normonatremia, is often associated with chronic alcoholism and may be asymptomatic. Histological confirmation of asymptomatic CPM is rare. We describe an unusual post-mortem case of extensive but asymptomatic CPM in a chronic alcoholic patient with normonatremia. The affected part of the pons contained thinly myelinated axons with appearances supporting remyelination. We suggest that remyelination may account for the subclinical nature of this patient's CPM.

Keywords: Alcohol; Asymptomatic; Central pontine myelinolysis; Post-mortem; Remyelination.

Fig. 1

a Post-mortem image of the fresh pons and medulla, opened sagitally from the ventral aspect. A red, central, triangular region of softening is seen with preservation of the surrounding parenchyma. b Sagittal T1 and (c) Axial T2 ante-mortem MRI sequences. The pons includes a trident-shaped focus of high T2 signal. Cerebellar atrophy is also noted, in keeping with the history of alcoholism. d Hypercellular pontine tissue, reflecting astrocytic gliosis and perivascular and parenchymal accumulation of chronic inflammatory cells (scale bar = 200 μm). e Staining with luxol fast blue and cresyl violet revealed a sharply demarcated region of reduced staining of myelin in the central part of the base of the pons, with good preservation of neurons (scale bar = 200 μm). f & g There was reduced labelling of myelin with anti-PLP1 in the affected region of pons (scale bar = 200μm). h Included within this region were many large-caliber but thinly myelinated axons (blue arrowhead), in contrast to the normally myelinated, large-caliber fibers in the adjacent pons (green arrowhead) (scale bar = 50μm)