Page 106 - The Vasculitides Volumes 2

82 Aleksandra Mineyko and Adam Kirton

(1) Location: Unilateral arteriopathy of the large vessels of the anterior circulation,
typically the distal internal carotid artery (ICA) and proximal segments of the MCA
and anterior cerebral artery (ACA).

(2) Arteriopathy characteristics: Unique angiographic appearance with unilateral focal
and segmental stenosis often with contiguous alternating areas of stenosis and
dilatation with a “banding” or “striated” appearance. More definitive features of
other arteriopathies such as dissection or Moyamoya are absent (see differential
diagnosis below).

(3) Time course: A dynamic nature with early serial vascular imaging often
demonstrating a fluctuating course of arterial changes on a scale of days to weeks.

(4) Resolution: A monophasic illness when followed over the longer term with follow up
imaging after 6 months confirming no progression, and variable resolution of arterial
changes.

A representative case example of this syndrome is presented in Figure 2. Ironically, the
most common syndrome of AIS in school-aged children is also the least understood.
Definitive evidence of an inflammatory pathophysiology is lacking in most cases, supporting
the consideration of alternative diagnostic terminologies. The diagnosis of TCA requires
angiography within 3 months of stroke demonstrating unilateral focal or segmental stenosis or
occlusion of the distal internal carotid or proximal MCA and ACA and lack of progression at
6 months [42, 44, 45]. Moreover, FCA shares the same features as TCA [6, 21] but facilitates
earlier diagnosis, respecting the inability to exclude progression until 6 months later; PVA
discussed below shares many of these features. Therefore, while a legitimate diagnostic entity
of its own [41, 43, 46], the non-progressive variety of large-vessel cPACNS shares many
features with other childhood cerebral arteriopathies, the spectrum of which should be
considered in the evaluation and management of affected children.

Bilateral large vessel arteriopathy without collaterals is a distinct, less common disease
classification within CASCADE [21]. Research to date has been limited but suggests large
vessel cPACNS may be bilateral in up to 20% of children [41, 47]. Whether this represents a
more widespread version of the more typical disease (akin to optic neuritis), a marker of
progressive large vessel cPACNS [41, 45], or falls within a spectrum of other bilateral
arteriopathies such as fibromuscular dysplasia or Moyamoya disease [45] remains to be
determined. Progressive large-medium vessel cPACNS also appears to be uncommon and is
more likely to present with long-standing, non-focal, diffuse symptoms such as
neurocognitive dysfunction, headaches, and seizures. Imaging may reveal multifocal, bilateral
parenchymal lesions on MRI, and multiple, bilateral stenoses of the distal vessels on
angiography [24, 41]. Ante mortem tissue diagnosis is not possible due to involvement of
larger intracranial arteries. The result is reliance on neuroimaging, specifically angiography,
which continues to improve but cannot definitively implicate inflammatory pathophysiology
or immediately identify a progressive from non-progressive prognosis. Long-term
surveillance and outcome studies are required to better understand the natural history and
predictors of recurrent forms of large-medium vessel cPACNS.

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