Thrombolysis in hemiballism: is it a rational choice?

Abstract

Different types of hyperkinetic movement disorders, such as hemiballism, hemichorea, dystonia and tremor, have been reported in patients with basal ganglia lesions due to ischemic or hemorrhagic stroke. Hemiballism, defined as a severe, violent, dysrhythmic and flinging excursion of a limb from a proximal joint, is one of the most distinctive signs of a vascular basal ganglia lesion [1]. The involuntary movements in hemiballism commonly involve the arm and the leg, as well as the facial muscles in about half of the cases. This relatively rare movement disorder has been classically ascribed to a lesion of the subthalamic nucleus (STN). However, the increasing use of neuroimaging in the last 20 years has highlighted the association between hemiballism and lenticular, caudate and even cortical lesions, usually involving the parietal lobe [1]. Stroke accounts for 50–75 % of cases of this disorder, which usually consist of lacunar infarctions or, less often, of hemorrhage. Other rarer vascular causes include arteriovenous malformations, venous angioma and subarachnoid hemorrhage. In addition, brief episodes of hemiballism may be a manifestation of a transient ischemic attack, involving either the carotid or vertebrobasilar territories. Neuroimaging studies have shown that several of these transient episodes are based on permanent infarcts [2]. A 74-year-old right-handed man, with a previous history of hypertension and dyslipidemia, presented a left motor disorder upon arrival at the emergency department (ED) of our hospital. The clinical examination highlighted slow, random, mostly proximal, involuntary movements involving the left arm and leg, associated with some grimacing on the homolateral side of the face. A cerebral computed tomography scan, performed 2.5 h after symptom onset, revealed mild signs of chronic vascular leucoencephalopathy. Although the patient had a National Institutes of Health Stroke Scale (NIHSS) score of zero [3], it was decided, on the basis of the clinical signs and after the exclusion of other possible causes for the hyperkinetic disorder (e.g. marked hypoglycemia, drugs), that he should undergo off-label thrombolysis with alteplase (67.6 mg iv), which was administered 3.5 h after stroke onset. Within 2 h of treatment, the involuntary movements were less pronounced, being limited to the left arm, mainly distal and of lower amplitude. A brain magnetic resonance imaging (MRI) examination performed the following day revealed a recent ischemic lesion of the right capsula extrema and insular cortex and the integrity of both subthalamic nuclei (Fig. 1). Another smaller lesion was found in the right temporal–parietal cortex. The patient’s symptoms resolved completely within 3 days without any symptomatic therapy. Hemiballism may be caused by a lesion in the contralateral STN, but, several studies have demonstrated that lesions outside the STN region, as in the present case, may be responsible for up to 85 % of the cases of hemiballism [4]. STN lesions reduce the striato-pallidal inhibitory influences along the basal ganglia circuit. This leads to reduced excitatory projection from the STN to the pars interna of the globus pallidus, which in turn disinhibits the thalamus and cortex, resulting in an involuntary movement. The somatosensory cortex also projects to the putamen, and may influence this basal ganglia circuit. It has been suggested that hemiballism caused by lesions of the STN is more severe than that caused by lesions located elsewhere, A. Correnti D. Toni C. Colosimo (&) Department of Neurology and Psychiatry and Neurovascular Unit, ‘‘Sapienza’’ University of Rome, v.le dell’Universita 30, Rome, Italy e-mail: carlo.colosimo@uniroma1.it