Keywords
cerebral arteriopathy - progressive vasculopathy - moyamoya
Palavras-chave
arteriopatia cerebral - vasculopatia progressiva - moyamoya
Introduction
Moyamoya disease (MMD) is a cerebrovascular disorder of rare incidence, characterized
by stenosis and progressive occlusion of the terminal portions of the internal carotid
arteries and their main branches in the circle of Willis.[1]
[2] The posterior circulation (vertebral arteries and basilar artery) can also be affected,
but this occurs with less frequency.[3] In addition to progressive stenosis, it is observed in this pathology the development
of a network of abnormally dilated collateral vessels at the base of the skull, which
can take on an aspect of smoke, named in Japanese as “Moyamoya.”[1]
[4] The clinical manifestation is variable, and the patient may be asymptomatic or they
may have, among other symptoms, headaches, seizures, focal neurological deficit and
even severe cases with ischemia or cerebral hemorrhage.[5]
[6]
[7] The present study aims to report two cases of patients, consecutively treated in
our service, who presented angiographic diagnosis compatible with MMD and distinct
clinical manifestations.
Case Report
Case 1–Female patient, 71 years old, hypertensive, presented with acute hemiplegia
on the left side and lowering level of consciousness. Magnetic resonance imaging (MRI)
of the cerebrum showed a right intraparenchymal frontoparietal hematoma ([Fig. 1]). Cerebral angioMRI showed occlusion of the terminal portions of the carotid arteries
([Fig. 2]). Complementary investigation was then performed with digital angiography by subtraction,
which showed severe internal bilateral stenosis of the supraclinoid carotid arteries,
with the presence of dilated collateral vessels at the base of the skull ([Figs. 3] and [4]). Additional exams showed the presence of a falcemic trait (hemoglobin dosage: S
¼ 36%).
Fig. 1 MRI of the encephalon – FLAIR sequence, axial cut – showing right frontoparietal
intraparenchymal hematoma.
Fig. 2 Cerebral angioMRI image – arterial phase, 3D TOF – showing significant reduction
of caliber in the terminal portions of the internal carotid arteries (arrows), with
dilated collateral vessels at the base of the skull (arrowheads).
Fig. 3 Digital angiography image by subtraction – anteroposterior incidence – showing severe
stenosis of the supraclinoid segment of the internal carotid arteries and their terminal
branches (anterior and middle cerebral arteries), with collateral vessels dilated
at the base of the skull (“Moyamoya vases”). The right internal carotid artery; D-F,
left internal carotid artery. The venous phase is normal (C and F).
Fig. 4 Digital angiography image by subtraction – profile incidence – showing severe stenosis
of the terminal portion of the left internal carotid artery and its branches (white
arrow), with dilated collateral vessels at the base of the skull (“Moyamoya vases”
– arrow heads).
Case 2–Female patient, 40 years old, with no previous history of comorbidities, arrived
at our service with chronic headache refractory to various types of treatment. Neurological
examination was normal. Cerebral angioMRI showed occlusion of the supraclinoid carotid
arteries and vertebral arteries in their intracranial segments ([Fig. 5]). Digital angiography was performed and evidenced subocclusive stenosis of the main
intracranial arteries, with the encephalic circulation predominantly nourished by
anastomosis between the left vertebral artery (intraforaminal segment – V2) with the
anterior spinal artery. This, in turn, vascularized the basilar artery, the posterior
cerebral arteries and the vessels of the anterior circulation through the posterior
communicating arteries ([Figs. 6] and [7]). A pial vascularization was observed through the marginal tentorial artery (also
known as the Bernasconi and Cassinari artery), originated in the intracavernous segment
of the right internal carotid artery ([Fig. 8]).
Fig. 5 Cerebral angioMRI image – arterial phase, 3D TOF – showing blood flow interruption
in the intracranial segments of the internal carotid arteries (arrows).
Fig. 6 Digital angiography image by subtraction showing: A, B, D, E, subocclusive stenosis
of the supraclinoid segment of the internal carotid arteries (white arrows); transdural
anastomosis with pial vascularization originated in the intracavernous segment of
the right internal carotid artery (black arrows); F, anastomosis between the intraforaminal
segment (V2) of the left vertebral artery and the anterior spinal artery (arrowheads),
which meets the increased caliber. Occlusion of the intracranial segment of the vertebral
artery (black arrow) is observed.
Fig. 7 Digital angiography image by subtraction with injection in the left vertebral artery
– anteroposterior incidence – showing vascularization of the basilar artery and its
branches through anastomosis with the anterior spinal artery.
Fig. 8 Digital angiography image by subtraction – profile incidence – showing pial vascularization
through the marginal tentorial artery (Bernasconi and Cassinari artery) originated
in the intracavernous segment of the right internal carotid artery.
Discussion
Moyamoya disease is a rare pathology, with a reported incidence of 0.086 cases per
100,000 individuals.[8]
[9] Originally thought to affect predominantly people of Asian origin, it is now observed
to afflict people from various ethnic backgrounds around the world. The incidence
among females is two times higher than in males.[10]
[11] It is characterized by the progressive occlusion of the terminal portions of the
carotid arteries and their main branches in the circle of Willis (anterior and middle
cerebral arteries), with the compensatory development of a network of collateral vessels
at the base of the skull (called “Moyamoya vases”). It usually affects the two cerebral
hemispheres and has two peaks of presentation: the first, around the age of 5 years
old, and the second, after 40 years old. The posterior circulation is affected in
a less frequent way.[3] Most children with this pathology manifest symptoms resulting from cerebral ischemia,
while adults present, more frequently, with intracranial hemorrhage.[3]
[9]
[12] In our study, we report the cases of two adult patients who presented to our service
with distinct clinical manifestations: one of them, with severe and focal neurological
deficit due to hemorrhage; the other, with progressive headaches and normal neurological
examination. Extensive diagnostic investigation with neuroimaging exams and laboratory
tests was performed, including thyroidopathy research, sickle cell anemia and atherosclerotic
disease.
Conclusion
Moyamoya disease is a pathology of rare incidence and difficult diagnosis, with multiple
forms of clinical presentation. Its diagnosis should be suspected in the clinical
context of patients with neurological alteration and progressive occlusion of the
carotid arteries and their intracranial terminal branches.
