Extrapontine Myelinolysis

Findings:
Axial CT images with and without contrast demonstrate patchy areas of symmetric low attenuation in the pons, thalami, and basal ganglia, without enhancement.

Differential Diagnosis:
central pontine/extrapontine myelinolysis, ADEM, MS less likely

Discussion:
Central pontine myelinolysis occurs infrequently when electrolyte disorders are corrected too quickly, and manifests clinically as spastic paraparesis, pseudobulbar palsy, or "locked in" syndrome. While the majority of cases are caused by rapid correction of hyponatremia or associated with alcoholism, a variety of electrolyte and metabolic disorders may have a role in CPM. Characteristic imaging features include symmetric hypodensity or signal abnormality in the pontine transverse fibers. These attenuation abnormalities can extend into the deep gray structures in up to 50%.

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