CT and MR Unilateral Brain Features Secondary to Nonketotic Hyperglycemia Presenting as Hemichorea-Hemiballism

Abstract

Hemichorea-hemiballism is an unusual hyperkinetic movement disorder characterized by continuous involuntary movements of an entire limb or both limbs on one side of the body. The acute onset of this disorder occurs with an insult in contralateral basal ganglia. Ischemic events represent the most common cause. Nonketotic hyperglycemia comes in second place. Nonketotic hyperglycemic hemichorea-hemiballism (NHH) is a rare cause of unilateral brain abnormalities on imaging studies confined to basal ganglia (mainly putaminal region as well as caudate nucleus). Subtle hyperdensity in striatal region can be found on CT studies whereas brain MR imaging typically shows T1 hyperintensity and T2 hypointensity in the basal ganglia contralateral to the movements. Diagnosis is based on both glucose levels and neuroimaging findings. Elevated blood glucose and hemoglobin A1c levels occur with poorly controlled diabetes. In this case report, our aim is to present neuroimaging CT and MR unilateral findings in an elderly woman secondary to nonketotic hyperglycemia presenting as hemichorea-hemiballism.

Figure 1

Findings: unenhanced axial brain CT depicts hyperdense striatum (caudate nucleus and putamen). This finding is better seen using narrow window width and higher center settings.

Figure 2

Axial T1-weighted sequence depicts right basal ganglia hyperintensity with unremarkable signal abnormality on axial T2-weighted.

Figure 3

ADC map shows slight decreased apparent diffusion coefficient in right basal ganglia. Symmetrical normal ADC values one month later.

Figure 4

Striking increase of T1-weighted signal intensity within right striatum one month after the onset of symptoms. Patient was asymptomatic when this MR study was performed.

Figure 5

Axial T2 gradient echo sequence shows no signal abnormality within right striatum but some scattered blooming artifacts within left thalami consistent with petechial hemorrhages.

Figure 6

Axial minimum intensity projection of susceptibility weighted imaging at 10-month follow-up depicts slightly hypointense signal within right striatum.

Figure 7

4-month and 10-month follow-up MR studies. Sagittal T1 depicts persistent hyperintensity within right striatum (green arrow), whereas a 10-month follow-up MR shows complete regression of signal abnormalities.