Central pontine myelinolysis

Summary Thirty-seven cases of central pontine myelinolysis (CPM) with miscellaneous underlying disorders were found in 1,000 consecutive autopsies, of which 636 brains were examined. The incidence of CPM in this study was 5.8%. The frequent underlying disorders were malignant neoplasms (43%), chronic pulmonary disease (27%), and chronic renal failure cases under dialysis treatment (14%). Fatty liver cirrhosis due to alcohol abuse was recognized in only one CPM case. In the present study, 78% of the CPM cases revealed either electrolyte disturbances or abnormal blood gas data, such as marked deviation of base excess and/or of serum pH in 62.5%, hyper- or hypochloremia (above 115 mEq/l, below 95 mEq/l) in 47%, hyper- or hyponatremia (above 150 mEq/l, below 130 mEq/l) in 25%, marked hypoxemia (less than 40 mmHg) in 12.5% and hypokalemia (below 3.0 mEq/l) in 9% of the CPM cases. The myelinolytic changes were localized in the basis pontis in 14 of 37 CPM cases and in the basis pontis and the cerebral and/or cerebellar white matter (extrapontine myelinolysis) in the remaining 23 cases. The extrapontine changes were also closely related to the electrolyte disturbances or the abnormal blood gas data. The results of this study suggest that myclin and oligodendrocytes in the basis pontis and cerebral and cerebellar white matter are vulnerable to abnormal levels of serum electrolytes and also to marked changes of the acid-base balance.