A Case of Non-ketotic Hyperglycemic Hemichorea and Fahr Syndrome

Non-ketotic hyperglycemic hemichorea (NHH) denotes acute hemichorea or hemiballism in patients with poorly controlled diabetes with striatal abnormalities seen on brain MRI. Here, we describe a case with diabetes mellitus and primary hypoparathyroidism who developed NHH with bilateral chorea due to the abrupt stopping of her diabetic regimen. She presented with subacute and progressive bilateral asymmetric chorea. Over the prior six months, she stopped following her diabetic regimen. Brain imaging showed features of diffuse brain calcifications suggestive of Fahr syndrome. Extensive blood investigations including genetic testing for causes of basal ganglia calcifications were unremarkable. Treatment with tetrabenazine and resumption of her diabetes medications slowly improved her chorea. This case highlights the importance of interpreting imaging findings in the context of the nature and time course of the chorea presentation. In addition, it emphasizes a systematic approach to interpreting diffuse brain calcifications with the appropriate investigations.