Brain-stem auditory evoked responses in diagnosis of central pontine myelinolysis

Central pontine myelinolysis (CPM) developed in association with acute adrenocortical insufficiency during correction of severe hyponatraemia in a 58-year-old woman. Repeated CT scanning and NMR imaging were normal from the onset of the illness. Electroencephalography and brain-stem auditory evoked responses showed abnormalities consistent with a brain-stem lesion, which resolved as the patient made a gradual but incomplete recovery. Our observations illustrate the value of electrophysiological monitoring in CPM and support the proposed association between this condition and the rapid correction of an electrolyte imbalance.