A 48-year-old chronic alcoholic is admitted with confusion and serum sodium of 108 mEq/L. Sodium is corrected rapidly over 24 hours. Two days later he develops flaccid quadriparesis and dysarthria. MRI shows symmetric T2 hyperintensity in the central basis pontis, sparing the ventrolateral pons and the corticospinal tracts. The most likely diagnosis is:

• A Central pontine infarct
• B Pontine capillary telangiectasia
• C Multiple sclerosis plaque
• D Osmotic demyelination syndrome ✓

Explanation

Rapid correction of severe hyponatraemia causes osmotic demyelination, classically a central T2-bright area in the pons that spares the periphery and corticospinal tracts, producing the trident appearance. A pontine infarct follows vascular territory and does not spare corticospinal tracts bilaterally and symmetrically. The temporal link to sodium correction is the discriminating feature against all vascular and inflammatory options.

Reference: Osborn's Brain, 2nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.