Irreversible striatal neuroimaging abnormalities secondary to prolonged, uncontrolled diabetes mellitus in the setting of progressive focal neurological symptoms.

Hemichorea-hemiballisum in patients with hyperglycemia and striatal hyperintensity on T1-weighted magnetic resonance imaging is now an accepted clinical entity. Usually, both the clinical syndrome and neuroimaging abnormalities are reversible. A transient, reversible metabolic impairment within the basal ganglion has been considered a possible cause of this disorder. However, the pathophysiology remains to be unclear. We report a 56-year-old man with a prolonged, uncontrolled hyperglycemia (HbA1C: 13.8%) and striatal hyperintensity on T1-weighted MR imaging presenting as reversible focal neurological deficit and irreversible neuroimaging abnormalities on the fourth month when blood sugar was under control (HbA1C 6.0 mg/dl). We hypothesize that neuroimaging abnormalities in our case may be a sequence of an "ischemic insult" caused by prolonged, uncontrolled hyperglycemia. Whether the signal abnormalities on neuroimaging studies or the clinical syndrome are reversible (patients with HCHB) or irreversible (such as in our case) are based on the degree of ischemic damage.