[A case of central pontine and extra-pontine myelinolysis demonstrated by magnetic resonance imaging].

A 74-year-old woman was admitted because of disturbed consciousness due to iatrogenic hyponatremia. At admission, her serum level of sodium was 88 mEq/l. The hyponatremia was carefully corrected with physiologic saline for three days at a rate of 0.75 mEq/h until the serum sodium concentration of 135 mEq/l was achieved. Her neurologic state gradually improved to respond to painful stimuli with her left hand during the first week of treatment, but further improvement was not noted after that. On the 16th hospital day, seizure developed on her face and left upper extremity. Although abnormal lesions were not detected by MRI of the brain at admission, those performed on the 15th hospital day revealed multiple uncommon lesions with Tl and Gd enhanced images. On Tl images areas of low signal intensity were found in the central pons and left putamen, which were more clearly demonstrated by Gd enhanced MRI images. These lesions were considered to be consistent with central pontine and extra-pontine myelinolysis (CPEM). In addition, a part of the right temporal cortex was enhanced clearly by Gd-DTPA, which was also thought to be an extra-pontine myelinolysis. These lesions were responsible for the development of neurological signs due to CPEM. To our knowledge, this is the first case in which a lesion in the cerebral cortex was revealed as an extra-pontine myelinolysis by Gd enhanced MRI images. Gd enhanced MRI is useful for detecting the extra-pontine myelinolysis as well as central pontine myelinolysis.