Non-ketotic hyperosmolar hyperglycemic chorea

* acquisition of data, literature review ** critical revision of manuscript for intellectual content, study supervision 1. Neurology Resident, Irmandade Santa Casa de Misericórdia of Porto Alegre, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brasil 2. Professor of Neurology, Irmandade Santa Casa de Misericórdia of Porto Alegre, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brasil 3. Professor of Neurology, Movement Disorders Division, Irmandade Santa Casa de Misericórdia of Porto Alegre, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brasil


INTRODUCTION
Chorea is a type of hyperkinesia characterized by the presence of involuntary, brief and unsustained movements caused by irregular sequential muscle activation that flows continuously in a disorderly and unpredictable way.¹It can be a manifestation of a primary neurologic genetic disorder, such as Huntington disease, or may occur as a neurologic complication of a systemic, toxic or metabolic cause, e.g., hypo/hypercalcemia or hyperglycemia.²Bedwell³, in 1960, was the first author to describe the rare clinical syndrome of nonketotic hyperosmolar hyperglycemic (NKHH) chorea.Although rare, it is a treatable condition and, therefore, should be recognized.

OBJECTIVES
To describe the clinical presentation and neuroradiologic findings of a typical case of NKHH chorea.

CASE
An 80-year-old man was admitted after the abrupt onset of involuntary movements that affected his whole body three months before admission.Medical history revealed diabetes mellitus and systemic arterial hypertension with irregular follow-up and poor glycemic control.
Neurological examination showed orofacial dyskinesias and gait associated choreoatheteroid move-

IMAGING IN MEDICINE
KEYWORDS: Chorea.Dyskinesias.Hyperglycemia.ments affecting mainly the left lower limb.Hemoglucotest was 462mg/dL on admission and brain MRI showed non-specific hyperintense areas in the basal ganglia on T1 (FIGURE).
The diagnosis of chorea secondary to nonketotic hyperosmolar hyperglycemic state was established through clinical and imaging findings, and the patient was managed with intensive diabetes control and haloperidol 5mg orally twice daily.There was a remarkable improvement in the next few days, and the patient was subsequently discharged with almost no symptoms.

DISCUSSION
Chorea pathophysiology is still not widely understood.However, unlike in parkinsonism and dystonia, intracortical inhibition of the motor cortex is normal. 4Semiquantitative analysis of single photon emission computed tomography in patients with hemichorea due to various causes suggests that there is an increase in activity in the contralateral thalamus, possibly due to disinhibition as a result of loss of normal pallidal inhibitory input. 5on-ketotic hyperglycemia-induced chorea occurs more often in women and is usually associated with very high blood glucose 6 .The exact pathophysiology of NKHH chorea remains unclear.However, many hypotheses as blood hyperviscosity, petechial hemorrhage, depletion of gamma-aminobutyric acid (GABA) and cerebral vascular insufficiency have been suggested. 7The correction of the metabolic abnormality usually is curative, but it can rarely continue for months after resolution of hyperglycemia. 8triatal permanent vascular changes may mean persistence of chorea for long periods. 9any of the metabolic choreas are associated with abnormalities on MRI scans.Nevertheless, the etiology of the MRI changes is not fully understood. 10epatocerebral degeneration and hyperglycemic chorea are often associated with high signal intensity on T1-weighted MRI involving the striatum and pallidum. 8hu et al. 11 , in a report of two patients with hyperglycemic hemichorea-hemiballism, found high signal intensities on T1-and T2-weighted images as well as on diffusion-weighted MRI accompanied by a reduction in diffusion coefficient, suggestive of hyperviscosity, rather than petechial hemorrhages, as the mechanism of edema in the striatum.This is also corroborated by another study of seven patients with hyperglycemic choreoathetosis using MRI and MR spectroscopy. 12Interestingly, the presence of high counts of acanthocytes may predispose patients with diabetes to develop hyperglycemic chorea.

FIGURE.
FIGURE.AXIAL (A) AND SAGITTAL (B) T1-WEIGHTED IMAGES SHOWING BILATERAL SPONTANEOUS HYPERINTENSE AREAS IN THE BASAL GANGLIA