Central pontine and extrapontine myelinolysis: from epileptic and other manifestations to cognitive prognosis

The objective of this study is to review the presentation, outcome and aetiology of central pontine and extrapontine myelinolysis (CPEPM) in a tertiary hospital center. The study method is a case series and included identification of patients from University of Montreal Health Centre archives database (1995-2007). All diagnoses were confirmed by neuroimaging or brain autopsy. Twelve individuals (25-66 years old) presented heterogeneous manifestations. Co-morbidities included diabetes insipidus (n = 2), haemodialysis (n = 1), cirrhosis (n = 3), gastroenteritis (n = 2) and potomania (n = 1). Aetiologies included rapid correction of severe hyponatremia (n = 6)/acute hypernatremia (n = 1); immediate (n = 2) or remote (n = 1 with recurrent cirrhosis) orthotopic liver transplantation (OLT) with tacrolimus-induced immunosuppression (n = 3); and chronic alcoholism (n = 4, two with hyponatremia). Four individuals died acutely. Two were lost to follow-up. Six had good motor or cerebellar recovery. Neuropsychological evaluations (n = 5/6) revealed a subcortical/frontal dysfunction. Cognitive impairment represented the major remaining lasting sequel (n = 4). Three salient clinical syndromes were observed: (1) predominant cerebellar presentation in individuals with alcoholism (n = 4); (2) significant alteration of consciousness at presentation (n = 4), all resulting in death (OLT, n = 3); (3) seizures persisting after natremia correction (n = 2). Clinical presentation of CPEPM is heterogeneous and can even include seizures. Cognitive impairment should be screened as it is a significant factor limiting return to normal life.