Central pontine myelinolysis with extrapontine myelinolysis

Excerpt

A 52-year-old man presented with anorexia, decreased level of consciousness, and behavioral disorders for 2 weeks. He was diagnosed with autoimmune hypophysitis and hypopituitarism and received high-dose corticosteroid pulse therapy 2 months ago. On admission, he had severe hyponatremia with serum sodium of 107 mmol/L (normal range 135–145 mmol/L). The serum potassium level was 3.69 mmol/L (normal range 3.5–4.5 mmol/L). To correct the sodium level, the patient received 3% hypertonic saline. The sodium level was corrected at a rate of 12 mmol/L/day and raised to 137 mmol/L on day 3. The patient regained consciousness for a short time but soon became lethargic again despite the normalized sodium level. The brain magnetic resonance imaging (MRI) revealed hyperintensities of the central pons and bilateral external capsules on T2 fluid-attenuated inversion recovery images and corresponding restrictive diffusion on diffusion-weighted imaging (DWI), suggesting central pontine myelinolysis (CPM) with extrapontine myelinolysis (EPM) (Fig. 1). Head and neck computed tomography angiography and cerebrospinal fluid examination were unremarkable. After we suspended the 3% hypertonic saline, the patient gradually regained full consciousness but remained quadriparesis in the following weeks. He was discharged and kept on hormone replacement therapy with corticosteroid and levothyroxine. At the follow-up 3 months later, the quadriparesis recovered and the serum sodium level was normal.

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