Diabetes and motor impairments

Dear Editor,

We present the case of a 88-year-old Spanish woman with a history of arterial hypertension treated with amiloride/hydrochlorothiazide who arrived at the emergency department with decreased level of consciousness, agitation, and disorientation in time. Her homecare service had detected elevated serum glucose levels (>500 mg/dL); the patient was given regular insulin and transported to the emergency department. In the previous 2 months, she had presented polydipsia and polyuria, and her consumption of solid food had decreased. She was afebrile and had no other symptoms. Physical examination revealed normal vital signs, mild dehydration, and no oedema of the lower limbs. The cardiopulmonary and abdominal exploration showed no anomalies. The neurological examination revealed disorientation in time with preserved orientation in place and person. The emergency department's complementary tests included an electrocardiogram and chest radiography, which yielded normal results; a blood biochemistry study (glucose 661 mg/dL, creatinine 1.88 mg/dL, urea 64 mg/dL); a complete blood count (no leukocytosis or neutrophilia); a urine test (no ketone bodies, high presence of bacteria in urine sediment); and a venous blood gas analysis, which revealed metabolic acidosis (pH 7.27, HCO₃ 18.8 mmol/L). Our patient received the first dose of antibiotics (amoxicillin/clavulanic acid) and continuous regular insulin infusion to normalise her glucose levels, which resulted in orientation in time, place, and person, and a normal level of hydration. She was subsequently admitted to the internal medicine department with the following diagnosis: simple hyperglycaemic decompensation in a patient with undiagnosed diabetes mellitus, nonketotic metabolic acidosis, acute renal failure of probable prerenal origin, urinary tract infection, and acute confusional state, which had been resolved. After admission to the internal medicine department, our patient experienced good clinical progress and biochemical normalisation. Basal insulin therapy achieved good glucose control. During hospitalisation, the patient began to experience choreic movements on the right side of her body; movements were initially mild but worsened over time. A cranial CT revealed no significant alterations. An MRI scan ordered by the neurology department revealed no lesions to the basal ganglia. Since the hemiballismus and choreic movements affecting the right side of the body were probably due to sustained severe hyperglycaemia, we initiated treatment with haloperidol, which achieved a good clinical response. Haloperidol was discontinued during hospitalisation after choreic movements had resolved due to normalisation of glucose levels. Our patient required no haloperidol after discharge.

Hemiballismus-hemichorea is a movement disorder characterised by continuous, rapid, violent, involuntary movements of the limbs.¹ It is caused by a lesion in the contralateral basal ganglia (including the striatum [caudate nucleus and putamen], globus pallidus, subthalamic nucleus, and substantia nigra), and more specifically, the contralateral striatum. Lesions in the putamen may be due to a number of causes. Although they are most frequently caused by vascular processes (ischaemic stroke in the subthalamic area), they can also result from injury to other areas including the thalamus, striatum, and cortical and subcortical regions.² The second most frequent cause is hyperosmolar hyperglycemic nonketotic syndrome (HHNS), which is characterised by hyperintensities in the contralateral putamen in CT images and MRI signal alterations in the contralateral putamen (hyperintensities in T1 and hypointensities in T2), all of which disappear as symptoms resolve.³ Other metabolic causes include hyperthyroidism, hypoparathyroidism, pregnancy, hyper- or hyponatraemia, hypomagnesaemia, hypocalcaemia, hypoglycaemia, acute hepatocellular degeneration, and nutritional disorders. Hemiballismus-hemichorea may also be of infectious, autoimmune, or neoplastic aetiology.

The pathogenic mechanisms by which hyperglycaemia causes a lesion in the basal ganglia are not clear. It has been hypothesised that it may be caused by a petechial haemorrhage in the area of the lenticulostriate artery that supplies the striatum^4–6; however, a biopsy of the putamen found no haemosiderin deposits.⁷ Another theory suggests hypofunction of the contralateral putamen, with decreased blood flow and metabolic activity.^8,9 Other researchers have proposed a vascular mechanism due to hyperviscosity secondary to hyperglycaemia.

Hemiballismus-hemichorea secondary to HHNS usually affects elderly patients with diabetes and may constitute the initial presentation of diabetes mellitus, as in our case; its mean age at presentation is 72 years,¹⁰ whereas hemiballismus-hemichorea of vascular origin presents at younger ages.¹ Incidence is similar for both sexes. This disorder seems to be more frequent in Asian people.

In addition to aetiological treatment, patients also receive symptomatic treatment with neuroleptics. Tetrabenazine may prevent late-onset dyskinesia.² Antiepileptic drugs (valproic acid, gabapentin, topiramate) may also be useful. Surgical treatment of the thalamus¹¹ or internal globus pallidus^12,13 is an option when symptoms do not resolve. Patients usually respond well to treatment¹⁴: symptoms tend to resolve after normalisation of glucose levels and radiological lesions in the putamen disappear after 3 to 11 months¹⁵.

Conclusions

Glucose metabolism should be analysed in patients with sudden-onset movement disorders, especially in the elderly, since symptoms may be reversible in some cases and most patients improve with appropriate metabolic control.

Funding

The authors have received no funding for this study.

Conflicts of interest

The authors have no conflicts of interest to declare.