Central pontine myelinolysis following 'optimal' rate of correction of hyponatraemia with a good clinical outcome.

Central pontine myelinolyis (CPM), an acute demyelinating condition of the brain stem, is a recognized complication of the treatment of patients with chronic hyponatraemia (hyponatraemia >48 h), particularly in those who abuse alcohol. The risk of CPM is believed to be associated with a rapid (>8 mmol/L/day) correction of the serum sodium concentration, which is said to lead to an osmotically-induced demyelination. CPM is also commonly believed to have a poor, and often fatal, outcome. We report the case of a 37-year-old female alcoholic patient who presented following a collapse, and who was hyponatraemic (serum sodium concentration 105 mmol/L). The rate at which the serum sodium concentration was corrected to normal was less than the 8 mmol/L/day guideline, but nonetheless she developed the clinical and radiological features of CPM. She made a good neurological recovery, however, and was able to be discharged from hospital. CPM does not necessarily have a bleak prognosis, and may occur even with optimal rates of correction of the serum sodium concentration. Clinicians should recognize that the outcome of CPM is not inevitably poor, and the complication may occur despite appropriate management. It is possible that CPM is a complication of the hyponatraemia itself, rather than the treatment of the biochemical disturbance.