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.