Osmotic demyelination syndrome (ODMS)
MR shows bilateral hyperintensities involving basal ganglia and pons (sparing periphery).
ODMS is acute demyelination caused by rapid shifts in serum osmolality usually seen after rapid correction of hyponatremia.
Location
- 50% in pons (CPM)
- Central fibers involved; peripheral fibers spared
- 50% extra-pontine sites (EPM)
- Basal ganglia (BG)
- Cerebral white matter (WM)
- Uncommon: Peripheral cortex, hippocampi
- Rare: Lateral geniculate bodies
- CPM + EPM = almost pathognomonic for ODMS
- Clinical profile: Alcoholic, hyponatremic patient with rapid correction of serum sodium. Key features of the neurologic exam include confusion, horizontal gaze paralysis, and spastic quadriplegia.
Imaging findings
MRI
- T2WI : Confluent hyperintensity in central pons with sparing of periphery and corticospinal tracts
Symmetric hyperintensity in BG, WM (EPM)
- T1WI : Mildly/moderately hypointense.
CT
Low density in affected areas (pons, BG, etc)
Treatment
a.Correct hyponatremia at a rate of 10 µmol/L/24 h; diligently avoid hypernatremia.
b. Alcoholic patients should receive vitamin supplementation