Acta Neurologica Belgica
https://doi.org/10.1007/s13760-018-0921-0

NEURO-IMAGES

Monochorea in chronic cerebral hypoperfusion with dopaminergic
transmission disruption
Takao Mitsui1,4

· Keiji Yoda2 · Masafumi Harada3

Received: 22 February 2018 / Accepted: 9 April 2018
© Belgian Neurological Society 2018

Keywords Monochorea · Hypoperfusion · Internal carotid artery · Infarction
A total of 1–4% of all patients with stroke develop some
type of hyperkinetic or hypokinetic movement disorder,
including chorea, ballism, athetosis, dystonia, myoclonus,
akathisia, and parkinsonian symptoms [1]. Hemichorea has a
similar pathophysiology to that of hemiballism and typically
occurs immediately after acute vascular events affecting the
subthalamic nucleus (STN). In the classic model of hyperkinesia, a lesion in the STN interferes with the transmission
of the indirect pathway, leading to an increased excitatory
output to the motor cortex from the thalamus. However, this
model has limitations in the extent to which it can explain
hemichorea/hemiballism [1]. There is little doubt that some
cases are caused by lesions outside the STN, although their
pathophysiology remains uncertain [1].
A 63-year-old woman presented with a 4-month history
of spontaneous rapid involuntary movements of the right
hand. The complex movements involved irregular flexion,

Electronic supplementary material The online version of this
article (https​://doi.org/10.1007/s1376​0-018-0921-0) contains
supplementary material, which is available to authorized users.
* Takao Mitsui
tmitsui@tokushima‑nh.hosp.go.jp
1

Department of Neurology, Tokushima National
Hospital, National Hospital Organization, 1354 Shikiji,
Kamojima‑cho, Yoshinogawa City, Tokushima 776‑0031,
Japan

2

Department of Neurosurgery, Tokushima Prefectural
Miyoshi Hospital, 815‑2 Shima, Ikeda‑cho, Miyoshi City,
Tokushima 778‑8503, Japan

3

Department of Radiology, Institute of Health Biosciences,
The University of Tokushima Graduate School, Kuramoto‑3,
Tokushima 770‑8503, Japan

4

Department of Clinical Research, Tokushima National
Hospital, National Hospital Organization, 1354 Shikiji,
Kamojima, Yoshinogawa, Tokushima 776‑0031, Japan

extension, and rotation of only the right hand and arm
(Video S1). Twelve years before developing the movements,
she had experienced a transient loss of consciousness due
to internal carotid artery (ICA) stenosis. Her neurologist
found no focal neurological deficits at the time. Her family
history was not significant. Our neurological examination
was unremarkable except for mild cognitive dysfunction.
Cranial magnetic resonance (MR) imaging showed a subcortical infarct in the left frontal region (Fig. 1a, c). Cranial MR
angiography did not show the left ICA (Figure S1A). Digital
subtraction angiography revealed a severe stenosis of the
left intracranial ICA with collateral circulation from the left
posterior to the left anterior cerebral arteries (Figure S1B).
Single-photon emission computed tomography (SPECT)
with 99mTc-ECD using easy z score imaging system revealed
cerebral blood flow impairment in the left frontal lobe and
left striatum (Fig. 1b, d). Diffusion tensor imaging showed
that the connectivity between the midbrain, striatum, and
frontal cortex was greatly impaired on the left side (Fig. 1e).
SPECT imaging with 123I-ioflupane showed that dopamine
transporter (DAT) binding was greatly reduced in the left
striatum (Fig. 1f).
Hemichorea or monochorea may occasionally occur in
carotid occlusive disorders wherein the lesions are not necessarily associated with the STN [2, 3]. This report presents
a case with upper limb monochorea and chronic hypoperfusion in the contralateral ICA region. An infarct lesion was
found in the left frontal subcortical region, although reduced
blood flow extended to the basal ganglia. This seems consistent with the assumption that functional hypoperfusion
rather than a structural infarct was the cause of the choreic
movement [2]. In this study, the reduced DAT binding in
the left striatum indicates a diminished presynaptic dopaminergic neuron integrity, which has not been recognized
in hemichorea/hemiballism of cerebrovascular disorders.
Furthermore, diffusion tensor imaging demonstrated

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Acta Neurologica Belgica
Fig. 1  a, c Cranial magnetic
resonance imaging showing a
subcortical watershed infarct
in the left frontal region. b,
d 99mTc-ECD single-photon
emission computed tomography (SPECT) using easy z
score imaging system shows
relative hypoperfusion in
the left frontal lobe and left
striatum. a, b Axial images; c,
d coronal images. e Diffusion
tensor imaging showing greatly
impaired midbrain–prefrontal
cortex connectivity on the left
side. f SPECT imaging with
123
I-ioflupane showing greatly
reduced dopamine transporter
binding in the left striatum

impaired midbrain–striatum–frontal cortex connectivity on
the affected side. On the other hand, pre- and post-synaptic
dopaminergic involvement and cortico-striatal signaling
impairment have been observed in the hereditary disorder
Huntington’s disease [4, 5]. Our findings suggest that the
pathognomonic mechanism of hemichorea/hemiballism in
cerebrovascular disorders is similar to that in Huntington’s
disease.
Author contribution TM supervised all aspects of the study, wrote, and
edited the manuscript. KY and MH interpreted the data. All authors
involved in the patient treatment participated in manuscript preparation.

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Funding The authors report no disclosures relevant to the manuscript.
Dr. Mitsui performs clinical and basic research funded by JSPS KAKENHI # 17H00873, #16H05281 and # 16K01492. Dr. Yorita reports
no disclosures. Dr. Harada performs neuroimaging study in his clinical
practice funded by JSPS KAKENHI #15K09926.

Compliance with ethical standards
Conflict of interest We declare that we have no conflicts of interest.
Ethical standards This case study has been approved by the ethics committee/institutional review board (IRB) of Tokushima National Hospital and has therefore been performed in accordance with the ethical
standards laid down in the 1964 Declaration of Helsinki and its later

Acta Neurologica Belgica
amendments. Written informed consent was obtained from the subject
for publication of this case report and accompanying images. A copy
of the written consent is available for review upon request.
Informed consent Written informed consent was obtained from the
individual included in the study.

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