Early manifestation of Moyamoya syndrome in a 2-year-old child with Down syndrome

Abstract

Moyamoya is a rare occlusive cerebrovascular disease characterized by progressive stenosis of the terminal portion of the internal carotid artery and the circle of Willis. Over time, collateral arteries are usually formed at the basal ganglia, the so-called Moyamoya vessels. The exact cause of Moyamoya disease is unknown, while Moyamoya syndrome refers to Moyamoya-like vasculopathy due to autoimmune diseases, neurofibromatosis type I, sickle cell disease, radiation, or rarely Down syndrome. Down syndrome is one of the most common genetic conditions, characterized by typical physical traits, associated with intellectual disability and a heterogeneous group of structural defects that may vulnerable the patient for the development of Moyamoya syndrome. The reported case is an unusual case of a 2-year-old boy with Down syndrome who presented to the hospital with seizures and right-side weakness. Brain MRI shows acute as well as old lacunar infarctions in both cerebral hemispheres. Catheter angiography of the patient demonstrates severe stenosis and occlusion of the large vessels of the circle of Willis, predominantly on the right side. The collateral vessels with the typical pattern of "puff of smoke" were also depicted in the right basal ganglia, which is a characteristic imaging finding for Moyamoya. The patient was managed conservatively and eventually discharged with a minimal improvement of the right-sided weakness. This case report is noteworthy because of the rarity of Moyamoya syndrome as a cause of a stroke as well as its possible association with Down syndrome.

Keywords: 3D-TOF, 3D time-of-flight; ACA, anterior cerebral artery; Angiography; CSF, cerebrospinal fluid; CT, computed tomography; CTA, computed tomography angiography; DWI, diffusion-weighted imaging; Down syndrome; ECA, external carotid artery; FLAIR, fluid-attenuated inversion recovery; ICA, internal carotid artery; Lacunar infarction; MCA, middle cerebral artery; MMD, Moyamoya disease; MMS, Moyamoya syndrome; MRA, magnetic resonance angiography; MRI; Moyamoya syndrome; PCA, posterior cerebral artery; SWI, susceptibility-weighted imaging; TIAs, transient ischemic attacks.

Fig. 1

DWI (a) and ADC (b) images of the patient, showing a small acute lacunar infarction in the subcortical area of the right parietal lobe (arrows). Axial T1W (c), T2W (d), and FLAIR (e) images showing multiple old lacunar infarctions in the white matter of both cerebral hemispheres in the watershed zones (indicated with red, green, and yellow arrows, respectively). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 2

Coronal (a) and axial (b) FLAIR images as well as T2WI (c) of the patient demonstrating atrophic changes of the right frontal cerebral cortex with the area of encephalomalacia and gliosis (white arrows) due to old ischemic insult. Foci of old lacunar infarctions are also seen in axial and coronal images (green arrows). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 3

Coronal (a) and sagittal (b) catheter cerebral angiograms demonstrating occlusion of the right MCA (white arrows) and right ACA (black arrows) in the proximal portions with a delayed filing of its distal portions via the collateral vessels (Moyamoya vessels), forming the typical appearance of “puff of smoke” (blue arrows). Coronal (c) catheter angiograms demonstrating severe narrowing of the M1 segment of the left MCA (white arrow), as well as the A1 segment of the left ACA (red arrow) without any obvious collateral vessel formation. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 4

Coronal (a) and sagittal (b) catheter cerebral angiograms demonstrating severe stenosis of the P1 segment of the right PCA (white arrows) in comparison to the normal P1 segment of the left PCA (red arrows). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)