Teaching Case

60-year-old lady with involuntary flinging movements of the left upper and lower limbs for one day. RBS - 600 mg/dl, Glycosylated Haemoglobin- 18.46%

Altered signal intensity was noted involving the right putamen which is hyperintense on T1WI and hypointense on T2WI. T2*W gradient images showed no evidence of significant blooming. No evidence of post contrast enhancement.

CT examination had shown no evidence of basal ganglia calcifications.
The above imaging findings along with uncontrolled hyperglycaemia and ballismus were suggestive of diabetic striatal disease (striatopathy)

Diabetic striatopathy is a unique syndrome comprising of movement disorder with contralateral neuroimaging abnormalities in the striatum [1]. It may be seen as a rare complication in diabetic patients with Non Ketotic Hyperglycemia (NKH) [2]. This is predominantly seen in elderly female patients with poorly controlled diabetes mellitus and majority of the reports mention a predilection for individuals of Asian descent [3, 4]. The underlying mechanism for the involuntary movements is hypothesised to be a hyperactive dopaminergic state due to GABA depletion in patients with NKH [5].

The characteristic imaging features include hyperdensity involving the striatum on plain CT which is an inconstant feature [6]. On MRI, the most characteristic and reproducible finding is hyperintensity involving the striatum on T1WI [6]. This may be associated with hypointensity on T2W and FLAIR images [6]. The reason for this hypointensity is attributed to petechial hemorrhage with hemosiderin deposition [2]. Findings on diffusion weighted images vary from unremarkable to restricted diffusion [1,6]. Proton MR spectroscopy may reveal decreased N- acetylaspartate / creatine ratio and an increased choline / creatine ratio [1].

Various theories have been proposed for the characteristic hyperintense MRI signal changes on T1 W images which include obliterative vasculopathy with prominent vascular proliferation involving the striatum, petechial haemorrhages involving putamen which may result from compromise of blood brain barrier due to underlying chronic focal cerebrovascular disease in diabetics and lastly myelinolysis [1, 6]. In hemichorea – hemiballismus, the contralateral basal ganglia is involved as seen in this case. In generalised chorea and ballismus, bilateral lesions may be seen.

The other important causes for T1 hyperintensity in the basal ganglia include Wilson’s disease which can be differentiated from diabetic straitopathy by the presence of T2 hyperintensity involving basal ganglia and thalamus [7]. The other conditions include hepatic encephalopathy, manganese toxicity and carbon monoxide poisoning [7]. Characteristic T1 hyperintensity with elevated blood sugar levels helps in clinching the diagnosis of diabetic striatopathy which on follow up images may show regression of imaging findings [2].

The importance of diagnosing this syndrome lies in the fact that it is a treatable condition and the patient’s symptoms can regress after correction of the blood glucose levels [3].