Hemichoreoathetosis following posterior parietal watershed infarction: was striatal hypoperfusion really to blame?

Acute Hemiballismus as the Presenting Feature of Parietal Lobe Infarction

It is widely believed that hemiballismus and chorea are suggestive of a basal ganglia subthalamic nucleus lesion; however, this not a rule. We report the case of a 63-year-old male with complaints of slurred speech, increased movement of the left half of his body, and headache. He had diabetes, hypertension, and a past medical history of stroke with residual weakness over the right side of his body. The patient developed the sudden onset of irregular, large amplitude, increased involuntary movements of his left upper and lower limbs with a flinging pattern. His blood sugar and serum osmolality were normal. His magnetic resonance imaging (MRI) showed an acute right parietal lobe infarction. Patients can experience hemiballismus with lesions other than the subthalamic nucleus in the basal ganglia. This is contrary to the classic belief that hemiballismus is associated with, and only with, lesions in the subthalamic nucleus. This manuscript describes a case of hemiballismus occurring in a patient secondary to a parietal lobe infarction.

Cortical hemichorea-hemiballism

Hemichorea-hemiballism (HCHB) was infrequently related to cortical lesions such as tumor or infarction. Although functional derangement of the basal ganglia (BG) or the thalamus (Th) was suggested, pathomechanism of HCHB secondary to cortical lesions remains uncertain. We recruited the patients with HCHB secondary to cerebrovascular diseases, excluding other causes such as hyperglycemia. All the patients were studied with brain magnetic resonance imaging/angiography (MRI/MRA) and single-photon emission computed tomography (SPECT). Those with only cortical abnormalities in neuroimaging studies were sorted out as the cases of cortical HCHB. Statistical parametric mapping (SPM) analysis of SPECT was performed to investigate the pathomechanism of cortical HCHB. Ten patients (three males and seven females) were included in our study. Six patients had acute BG lesions with SPECT abnormalities, and one had old BG lesions with abnormal SPECT. Three patients were classified as cortical HCHB with lesions only in the frontal and parietal cortices in MRI and SPECT. SPM analysis revealed additional hypoperfusion in frontal areas, leaving BG and Th free of any perfusion abnormalities. Although cortical HCHB was strictly defined by MRI and SPECT, cortical HCHB was not uncommon (30 %). Further analysis showed intertwined networks among the frontal and parietal lobes for cortical HCHB. Cortical dysfunction is important in the pathogenesis of cortical HCHB even without significant involvement of BG and Th.

Vascular chorea in adults and children

Chorea may occur as part of the symptomatology of acute stroke; it occasionally also may be delayed or progressive. Patients with vascular-related chorea typically present with an acute or subacute onset of chorea of one side of the body (hemichorea), contralateral to the lesion. Cerebrovascular disease is the most common cause of sporadic chorea. Lesions are most frequently found in the thalamus and lentiform nucleus, and less often in subthalamic nucleus. The differential diagnosis of choreic syndromes relies not so much on differences in the phenomenology of the hyperkinesia but the age at onset, mode of onset, time course, family history, drug use, distribution of chorea in the body, and presence of accompanying neurological findings. Magnetic resonance imaging is preferred to demonstrate the presence of strategic small lesions in regions that are difficult to image with computed tomography, such as the globus pallidus, thalamus, and subthalamic nucleus. Although the prognosis of hemichorea can be benign, the long-term prognosis is not specifically determined by the hemichorea but by the long-term prognosis of stroke patients. Symptomatic treatment with antichoreic drugs may be necessary in the acute phase. Surgery is rarely indicated to treat vascular chorea.

No evidence of perfusion abnormalities in the basal ganglia of a patient with generalized chorea-ballism and polycythaemia vera: analysis using subtraction SPECT co-registered to MRI

Polycythaemia vera is a well-known cause of symptomatic chorea, however, the pathophysiology of this correlation remains unclear. We report on a patient with generalized chorea-ballism associated with polycythaemia vera, and we present the findings of 99mTc-hexamethylpropylene amine oxime (HMPAO) SPECT done in both the choreic state and the non-choreic state. The SPECT during both the choreic and the non-choreic states did not reveal any definite perfusion changes in specific regions of the brain, as compared with 6 age-matched controls. In addition, the subtraction SPECT co-registered to MRI (SISCOM) analysis did not show any difference in cerebral blood flow during the choreic and non-choreic states. This result suggests that the basic mechanism of chorea associated with polycythaemia vera does not appear to be associated with a reduction in cerebral perfusion to a specific cerebral area, such as the basal ganglia or its thalamocortical connections.

Hemichorea as an initial manifestation of moyamoya disease: reversible striatal hypoperfusion demonstrated on single photon emission computed tomography

We describe a case with unilateral moyamoya disease that showed progressive hemichorea as an initial manifestation. Single photon emission computed tomography showed perfusion defect in the contralateral basal ganglia although magnetic resonance imaging was unremarkable. Hemichorea improved along with normalization of perfusion after bypass surgery, suggestive of striatal hypoperfusion as the cause of hemichorea.