Moyamoya disease-induced hemichorea corrected by indirect bypass surgery

Corticostriatal Hypermetabolism in Moyamoya Disease-Induced Hemichorea: Two Case Reports and a Literature Review

Moyamoya disease (MMD) is a rare cause of chorea, and its pathophysiological mechanism remains unclear. We explore the use of cerebral positron emission tomography (PET) to study brain functional connectivity in 2 patients with MMD-induced hemichorea. Abnormal metabolism of brain was analyzed by ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET images. Dopamine transporters (DAT) PET evaluated the integrity of the cerebral dopamine system. A comprehensive systemic literature search of the PubMed database was also conducted. The ¹⁸F-FDG imaging of our patients showed no responsible hypometabolism in affected brain areas, while hypermetabolism in the affected caudate nucleus, putamen and fronto-parietal areas could be seen. DAT PET imaging was normal in patient 1 (a 23-year-old woman), while remarkably reduced DAT binding was seen in the left striatum of patient 2 (a 48-year-old woman). The literature review of 9 publications revealed that 11 patients who underwent single photon emission computed tomography (SPECT) showed cerebral hypoperfusion in the cortex and subcortical area; ¹⁸F-FDG PET was performed in 3 cases, which revealed hypermetabolism in the affected striatum in 2 cases. These findings suggest that the striatal and cortical hypermetabolism in the first patient result from underactivity in indirect pathway from basal ganglia-thalamocortical circuits, causing increased activity of excitatory glutamatergic thalamostriatal and thalamocortical projection neurons. The collateral vessels in the basal ganglia might lead to disruption of normal basal ganglia signaling. A dominant left hemisphere with corpus callosal connections to the right basal ganglia resulting into left hemichorea is the most probable explanation for the second patient. We have identified abnormal functional connectivity in basal ganglia-thalamocortical circuits in patients with MMD-induced chorea highlighting the corticostriatal pathway plays an important role in the pathogenesis of MMD-induced chorea.

Reversible striatal hypermetabolism in chorea associated with moyamoya disease: a report of two cases

BACKGROUND

The pathophysiological mechanism of chorea as a presentation of pediatric moyamoya disease remains unknown, although ischemia is suspected as a likely cause. The authors describe two cases of pediatric moyamoya disease, both of which presented with hemichorea in the stable phase after successful bypass surgery.

CLINICAL PRESENTATION

Cerebral blood flow was almost normal in one case and decreased in the basal ganglia and watershed area in the other case due to infarcts occurring before surgery. In both cases, ¹⁸F-fluorodeoxyglucose positron emission tomography revealed elevated glucose metabolism in the corresponding side of the striatum, which reverted to normal after recovery from chorea. Magnetic resonance angiography revealed a dilated and extended lenticulostriate artery at the exact site of the hypermetabolic lesion.

[Convulsive syncope associated with transient hemodynamic ischemia in the basal ganglia]

The pathophysiology of convulsive movements in patients with convulsive syncope remains unclear. Here, we report a patient with convulsive syncope whose convulsive movements seemed to be associated with transient hemodynamic ischemia in the basal ganglia. A 74-year-old man had 1-year history of orthostatic hypotension and transient clonic jerks in the limbs and trunk, predominantly in the right upper limb. His convulsive movements were evoked approximately 1 minute after sitting up or standing up from the supine position and lasted for several tens of seconds. He felt mild faint while the convulsive movements lasted, but he was oriented and could follow simple commands. He was diagnosed as pure autonomic failure. Video-electroencephalogram (EEG) recorded generalized slows without any epileptiform discharges when the symptoms appeared. Single-photon emission computed tomography (SPECT) was performed using split-dose method to evaluate the change in blood flow when the convulsive movements appeared. During symptoms, a significant decrease in blood flow was revealed in the anterior part of the left basal ganglia, bilateral frontal areas, and right cerebellar hemisphere. An alteration in the functional balance between the basal ganglia and the cerebral cortices may play a role in the generation of convulsive movements in patients with convulsive syncope.

Hemiballismus

Hemiballism is a relatively rare hyperkinetic movement disorder characterized by involuntary, violent, coarse and wide-amplitude movements involving ipsilateral arm and leg. Although classically related to lesions in the subthalamic nucleus, in clinical-radiological series of hemiballism most patients had lesions outside this nucleus, involving mainly other basal ganglia structures. It has been suggested that abnormal neuronal firing patterns in the internal segment of the globus pallidus may be related to the pathogenesis of hemiballism. Stroke is the most common cause, but in recent years an increasing number of patients with hemiballism associated with nonketotic hyperglycemia or with complications of human immunodeficiency virus (HIV) infection have been reported. Contrarily to what was stated in older literature, hemiballism has, in general, a relatively good prognosis. Depending on the underlying causes, many patients may experience spontaneous improvements or remissions. Treatment should be directed to the cause of hemiballism. Symptomatic treatment includes the use of drugs, particularly blockers of striatal D2 dopamine receptors and tetrabenazine. Surgical treatment, especially pallidotomy, is a therapeutic option for the minority of patients with severe persistent disabling hemiballism.

Movement disorders associated with moyamoya disease: a report of 4 new cases and a review of literatures

The aim of this study was to define the clinical characteristics of patients who developed movement disorders in association with moyamoya disease (MMD). Using PubMed and medical records of our hospital from 1985 to 2008, we searched for patients who developed movement disorders in association with MMD. This study included 38 patients described in previous studies and 4 patients found in the medical records. The onset of movement disorders was thought to be sudden. In 13 patients, the movement disorders were precipitated by hyperventilation or emotional stress. Twenty-seven of the 42 patients developed chorea, 4 patients developed dystonia, and 4 developed a mixture of both. The movement disorders of the remaining 7 patients were described as dyskinesia. A third of the 42 patients developed bilateral movement disorders, and their mean age was younger than that of those with unilateral movement disorders. In 37 of the 42 patients, brain imaging studies showed ischemic lesions, but the remaining 5 patients showed no parenchymal lesions. Cerebral perfusion studies showed hypoperfusion in the basal ganglia and in the cerebral cortical areas. Most patients improved whether they were treated or not. MMD must be included in the differential diagnosis of the sudden onset of dyskinesias, particularly chorea and focal dystonia. Even in patients with no parenchymal lesion in brain imaging studies, cerebral angiography and cerebral blood perfusion studies must be performed, if they develop a sudden onset or recurrent movement disorders preceded by emotional stress or hyperventilation.