Teaching Case

A 66-year-old female with type II diabetes mellitus since 25 years on irregular treatment, presenting with complaint of random, uncontrollable, involuntary, jerking movements of left upper limb and left lower-limb, her random blood sugar was found 580 mg/dl, HbA1c -17.46% and urine ketones ++.

Non contrast computed tomography of the brain revealed diffuse hyperdensity involving right striatal region (caudate nucleus and putamen). (Figure 1)

Non-contrast MRI study of the brain revealed altered signal intensity area involving right caudate nucleus and right putamen which appears hyperintense on T1WI (Figure 2) and hypointense on T2WI and FLAIR (Figure 3a and 3b), T2*W gradient image show no evidence of blooming [figure 4] and DWI (Figure 5a) shows hypointense signal intensity with no evidence of diffusion restriction on ADC (Figure 5b)

Diabetic striatopathy is a unique complication of diabetes, more commonly seen in T2DM than T1DM. It is more commonly seen in elderly Asian females with poorly controlled diabetes mellitus [1, 2]. It may be seen as a rare complication in diabetic ketoacidosis (DKA) [3].

The underlying pathophysiology for hyperkinetic movements is hypothesised to be a hyperactive dopaminergic state due to suppressed activity of the Kreb’s cycle during hyperglycemic crisis, leads to metabolism of gamma amino butyric acid (GABA) into succinic acid via semialdehyde pathway, leading to rapid depletion of GABA levels [4]. Thus, GABA depletion causes disinhibition of the thalamus by the medial globus pallidus, resulting in hyperkinetic movements. On the other hand in DKA, acetoacetate produced from the liver is available to produce GABA, therefore, preventing its low levels, hence striatopathy rare in DKA [5]

Clinically patient with diabetes mellitus presents with dyskinesias including chorea-ballism which can be either unilateral or bilateral depends on either unilateral or bilateral corpus striatum involvement is there. In unilateral condition contralateral striatum is involved. [6]

Plain computed tomography shows hyperdensity involving striatum, MRI shows hyperintensity on T1WI [9], hypointensity on T2WI and FLAIR images[9], Findings on diffusion-weighted images vary from unremarkable to faint restricted diffusion [1,9] no evidence of blooming on T2*W gradient image [7].

The role of imaging is to rule out other cause of hemiballismus, particularly striato-capsular infarct which can be differentiated by high signal on DWI with restriction on ADC.

Wilson’s disease which can be differentiated by hyperintensity on T2WI involving basal ganglia and thalamus. [8]

Elevated blood sugar levels, chorea-ballism involving left side with hyperdensity on plain CT and hyperintensity on T1WI on right side help in making the diagnosis of diabetic striatopathy. [10]

Treatment: This is a reversible condition with prompt management of the hyperglycemia. [1, 2] Restoration of homeostasis achieved by fluids and insulin infusion. Some patients require additional drugs like neuroleptic agents, dopamine-depleting agents, GABAergic drugs and SSRI.[6]

Take home message: Diabetic ketoacidosis presenting as ‘‘Diabetic striatopathy” is a rare complication. Early recognition and treatment are rewarding.

Written informed patient consent for publication has been obtained.