Hyperglycaemia presented with Chorea: a case report from primary care

Annie KY Or 柯嘉茵，Catherine XR Chen 陳曉瑞

HK Pract 2021;43:120-123

Summary

Chorea is an involuntary hyperkinetic movement disorder characterised by rapid and unpredictable contractions over mainly distal limbs, the face and the trunk. We report on the case of an 89-year-old lady encountered in the General Outpatient Clinic, who presented with choreiform movements due to her hyperglycaemia. She was admitted into hospital and subsequently recovered completely after correction of her hyperglycaemia.

There was also an associated radiological finding of hyperdensities in her bilateral basal ganglia which is now regarded as the Chorea Hyperglycaemia Basal Ganglia Syndrome. Although the pathophysiology of this syndrome is still unknown, it is vital for family physicians to be familiarised with this condition because it is one of the rare and reversible complications of uncontrolled diabetes; to better ensure an early diagnosis, appropriate management and good patient outcome.

摘要

舞蹈症是一種不自主的運動過度性障礙，其主要特徵是四肢，面部和軀幹快速且不可預測的肌肉收縮。我們報告了一例在普通科門診就診的糖尿病患者，她因過高的血糖而出現了舞蹈症。轉介入院後腦部電腦掃描檢查顯示雙邊基底核有高密度病灶，診斷為非酮症高血糖偏側舞蹈症（C-H-BG）。高血糖得到控制後，舞蹈症也完全康復。儘管該綜合症非常罕見， 而且其病理機制尚不清楚，但對於家庭醫生而言，能及早確診C-H-BG尤其重要，因為及時的治療可以將舞蹈症完全根治，逆轉因高血糖而帶來的併發症。

Introduction

Chorea is a rare neurological manifestation with many different causes, the most well-known is Huntington’s Disease (HD) which is an autosomal-dominant hereditary disease. Among the acquired causes which lead to more acute onset of chorea, a large proportions are caused by central nervous vascular lesions (40%); other causes, such as autoimmune, inflammatory particularly Sydenham chorea, metabolic, infectious agents, toxins, drugs or structural lesion in the basal ganglia, should also be considered.

This present case illustrates the need to be aware of hyperglycaemia as a cause of hemiballism/hemichorea, which is the hallmark of the Chorea Hyperglycaemia Basal Ganglia syndrome (C-H-BG ).

Case Presentation

Madam CSK is an 89-year-old lady. She is a non-smoker and non-drinker. She has regularly been followed up at a General Out-patient Clinic (GOPC) of the Hospital Authority of Hong Kong for management of hypertension, Type 2 diabetes mellitus (T2DM) and ischemic heart disease.

History

She was seen on 7/7/2017 as a routine follow-up (FU) for her chronic diseases. Her medication list included Aspirin, Pantoprazole, Gliclazide, Metformin, Lisinopril, Nifedipine retard and Simvastatin. Latest diabetic complications screening performed on 30/6/2017 showed her HbA1c level was 7.1%, creatinine level was 105µmol/L and lipid profile was normal. There were no diabetic microvascular complications. Her following scheduled FU was 27/11/2017 but she defaulted the FU when she did not turn up after that.

Madam CSK then attended the above mentioned clinic on 2/2/2018 for episodic care.

Clinical examination

She complained of subacute onset of involuntary movements over her left upper limb in July 2018 for two days. There was no concomitant headache, dizziness, slurring of speech, dysphasia, blurring vision or hearing problem. She did not have any limb weakness or numbness, nor any limb rigidity or tremor. There was no fever or any coryzal symptoms suggestive of infective causes either. She did not have any head injury earlier, nor had she taken any over-the-counter drug lately. There was no family history of hereditary problems like HD or other neurodegenerative diseases. No decline in her cognitive function or behavioural changes were noted either.

On physical examination, her general condition was stable with a high blood pressure reading of 160/85 mmHg. She was afebrile, conscious and alert, and was oriented in time, place and person. Neurological examination yielded no grossly remarkable finding, except the subtle involuntary movement of a choreo-ballismus nature with her left entire upper limb. There was no dystonia or rigidity. The sensation and power of her four limbs were normal. Initial impression was chorea of subacute onset over her left upper limb from a suspected vascular cause. The patient was therefore urgently referred to the Accident and Emergency Department (AED) for further management.

Upon admission to AED, the patient was noted to be mildly dehydrated with a high spot glucose level of 20.6 mmol/L and was given an injection of a short acting insulin. The patient was then admitted to the medical ward for further work-up. Blood tests revealed that her creatinine level had shot up to 203µmol/L from baseline of 105µmol/L 8 months previously. Otherwise, the complete blood picture, electrolytes, calcium, magnesium, liver function, thyroid function, effective serum osmolality, bicarbonate and ammonia level were all normal.

Subsequent findings and final diagnosis

Computed Tomography (CT) brain was performed and there were hyperdensities in her bilateral basal ganglia region, age-related cerebral atrophic changes and periventricular chronic ischemic changes (Figure 1). She was later diagnosed to have the C-H-BG syndrome.

The subsequent blood testing showed that her hemoglobin A1c level (HbA1c) increased from 7.1% on 30/6/2017 to 10.0% on 3/2/2018 in the 8 months. Although Madam CSK was reported to have good drug compliance, she had defaulted regular follow-up and the dose of her oral hyperglycemic agent had also been decreased in a previous visit, both of which could have contributed to the worsening of her HbA1c control. After admission, her glycemic control was modified by a new drug regime and titrated insulin dose.

The chorea movements subsided after better control of serum blood glucose level in hospital. CT brain was repeated on 6/2/2018, which revealed no interval changes. She was then discharged home without any further neurological sequelae. She continued her FU in GOPC for further management of her DM with quarterly monitoring of her blood HbA1c. Subsequent investigations done 3 months later showed that her HbA1c showed a decreasing trend.

Discussion

Chorea, ballism and athetosis are hyperkinetic movement disorders with a shared pathophysiology and overlapping aetiologies. Regarding the aetiology, besides the well-known HD (10%), there is an exhaustive list of differential diagnoses including haemorrhagic or ischemic stroke, neoplasm, systemic lupus erythematosus, Wilson’s disease, drug induced and metabolic conditions, with the latter being often underestimated in clinical practice. Examples of drugs that cause chorea are neuroleptics, levodopa, anticholinergics, oral contraceptives, antihistamines, amphetamines, cocaine, phenytoin, and tricyclics. Among the metabolic conditions, poorly controlled diabetes could be one of the causes, accounting for about 1% of all acquired chorea cases, based on findings from a US study done from 2000 to 2014.¹ In children, Sydenham Chorea accounts for up to 96% of acute chorea cases.²

C-H-BG syndrome is a known complication of nonketotic hyperglycaemia among patients with a background of uncontrolled T2DM. It is also termed as “diabetic striatopathy”, which refers to chorea caused by hyperglycemic states and mostly involves the basal ganglia as noted via imaging studies.³ It is best characterised by the manifestation of hemichorea-hemiballism with uncontrolled blood sugar levels. The striatal abnormalities in neuroimaging could be contralateral to hemichorea or bilateral in some cases.³

D-H-BG syndrome was mainly reported in elderly Asian population with a female predominance. While hyperglycaemia in elderlies being a risk factors, C-H-BG syndrome could occur in long standing diabetes, or manifest as first presentation leading to new diagnosis of diabetes.

The mean serum glucose level measured after the onset of chorea was 481.5 mg/dl (26.8mmol/L), HbA1c level was 14.4%, and serum osmolarity was 305.9 mmol/kg.⁴

67% of D-H-BG syndrome cases present as unilateral chorea with about 25 % reporting bilateral symptoms. C-H-BG syndrome should be considered when characteristic T1 and T2 hyperintense abnormalities are observed on MRI, and there is hemichorea-hemiballism with a history of uncontrolled T2DM.

Common differential diagnosis would be ketotic hyperglycaemia, which usually affects T2DM patients of relatively younger age, with the presence of ketones in blood and urine and marked metabolic acidosis, but negative neuroimaging findings.

Based on the available literature, we understand that the majority of patients with C-H-BG syndrome have a benign clinical course that can be managed medically, early recognition and good glycemic control could lead to total resolution of choreiform symptoms without any complications. Therefore, C-H-BG Syndrome is being recognised as a benign disorder with a good prognosis.

The exact pathogenesis of C-H-BG syndrome is not yet fully understood. It is postulated that the synergistic effects of uncontrolled hyperglycaemia and vascular insufficiency due to hyperviscosity may cause an incomplete transient dysfunction of the striatum, which eventually leads to hemichorea-hemiballism in these patients.⁵

Conclusion

Chorea is a rare clinical condition which mostly requires inpatient management. C-H-BG syndrome is a rare manifestation of poorly controlled T2DM that clinicians should be aware of. Since DM is one of the commonest disease entities encountered every day in primary care, all family physicians should be on high alert with regards to the patient’s glycemic state when they come across patients with an acute onset of chorea, especially for those old aged patients with a background history of poorly controlled diabetes. Blood glucose checking by glucometer in the clinic can provide an immediate hint on the possible diagnosis before we refer the patient to the hospital. C-H-BG syndrome should be on the top of the differential list when the characteristic radiological findings of hyperdensities in the basal ganglia are observed. Since this condition is reversible with the correction of hyperglycaemia, prompt recognition and treatment are essential to avoid adverse outcomes.