Key-words:
Acute stroke - internal carotid artery dissection - magnetic resonance angiography
Introduction
Stroke is relatively rare in children but can lead to significant morbidity and mortality.
Acute ischemic stroke in children has an incidence ranging from 3 to 8 per 100,000
children per year.[[1]] The likelihood of an acute ischemic stroke being secondary to an arterial dissection
is reported to be as high as 20%.[[2]] We present the case of a right internal carotid artery (ICA) dissection (ICAD)
that led to a thromboembolic ischemic stroke.
Case Report
A previously healthy 10-year-old girl who presented with a headache and left hemiparesis
was immediately transferred to our hospital. She had a manual muscle testing (MMT)
score of 1 and also had left hemianopia and left hypoesthesia. Computed tomography
(CT) showed no abnormal lesion [[Figure 1]]a. Diffusion-weighted magnetic resonance imaging (MRI) of the brain showed a signal
lesion in the right posterior limb of the internal capsule [[Figure 1]]b, and magnetic resonance angiography (MRA) showed poor visualization of the right
ICA, and a defect area was present in a part of the supraclinoid portion of the right
ICA [[Figure 1]]c. MRA of the neck showed a thin and segmented stenosis in the right cervical ICA
[[Figure 1]]d. T1 fat-saturated brain imaging showed a hyperintensity along the vessel wall
[[Figure 1]]e. Three-dimensional CT angiography showed no abnormal findings in the aortic arch
and other major arteries [[Figure 1]]f. Based on the clinical and radiological findings, the patient was diagnosed with
ischemic stroke due to right ICAD. No cervical arterial vessel redundancy, tortuosity,
or fibromuscular dysplasia was noted, and her transthoracic echocardiogram was normal.
Serum autoimmune markers, inflammatory markers, and hypercoagulation panel were unremarkable.
Moreover, given that she had no history of trauma, the ICAD was thought to be spontaneous.
She received 5 days of intravenous argatroban (40 mg/day) followed by oral aspirin
(100 mg/day). At 1 month, the infarction had not increased. In addition, the imaging
appearance of the dissection did not change. Three months later, her hemiparesis markedly
improved with an MMT score of 4, and the left hemianopia and left hypoesthesia had
disappeared.
Figure 1: (a) Computed tomography showing no abnormal lesion. (b) Diffusion-weighted imaging
showing areas of restricted diffusion involving the right internal capsule. (c) Magnetic
resonance angiography of the brain showing that a defect area was present in the right
internal carotid artery (arrow). (d) Magnetic resonance angiography of the neck showing
a thin and segmented stenosis in the right internal carotid artery. (e) T1 fat-saturated
image of the brain showing a hyperintensity along the vessel wall (arrow). (f) Three-dimensional
computed tomography angiography showing no abnormal findings in the aortic arch and
the other major arteries
Discussion
ICAD is one of the most important causes of acute ischemic stroke in children. Risk
factors for ICAD in children include head-and-neck injury, connective tissue disorders
(such as Ehlers–Danlos syndrome or Marfan's syndrome), and the male sex.[[2]] Moreover, some reports show that there may be the relationships between rotational
changes and tolerability to G forces and dissection, for example, with a water slide
[[3]] and roller coaster.[[4]] However, it is important to note that spontaneous ICAD is frequently encountered
as in the present case.
The diagnosis of ICAD is often difficult. MRI/MRA has become the first-line imaging
modality for patients with suspected dissection. It is noninvasive, requires no radiation,
and simultaneously images for dissection and acute ischemic stroke. MRI can visualize
the intramural hematoma with T1 fat-saturated imaging as a hyperintensity along the
vessel wall like in the present case.
The treatment of ICAD remains controversial as controlled studies are lacking. The
utility of antiplatelet agents and anticoagulation remains unclear. According to previous
studies in adults, thromboembolism is the primary mechanism of acute ischemic stroke
in ICAD, and anticoagulation therapy is suggested for 3–6 months.[[5]] However, no prospective randomized study has been performed to support this treatment
regimen. Moreover, even the use of antiplatelet therapy is controversial. In a recent
randomized controlled trial, it was not established whether antiplatelet therapy or
anticoagulation was superior.[[5]]
In the present case, we initiated argatroban therapy in the acute stage, and after
5 days of anticoagulation, we commenced antiplatelet therapy and discontinued the
anticoagulation. This therapy regimen appeared safe and effective.
Because of the rarity of acute ischemic stroke, diagnosis is often delayed and cases
may remain under- or mis-diagnosed. In fact, CT could not detect any abnormal lesions
in the present case. As early diagnosis of ICAD is crucial for prompt treatment in
children with unexplained gross neurologic abnormalities, ICAD should be suspected
and MRI should be performed even without a history of blunt trauma to the head and
neck.
Declaration of patient consent
The authors confirmed that all appropriate patient consent forms have obtained. In
the form, the patient and her parents have given consent for her images and other
clinical information to be reported in the journal. The patient and her parents understands
that her names and initials will not be published and due efforts will be made to
conceal their identity.
