Second edition

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278 Other major syndromes
Infarction in the area of distribution of the inferior division
generally causes a contralateral hemianopia or quadrantopia.
With right-sided infarction, a delirium, often accompanied
by agitation (Caplan et al. 1986) is common and
prosopagnosia may also be seen. With left-sided infarction,
in cases where the angular artery arises from the inferior
division, one typically sees a sensory aphasia; delirium may
also occur but is less common than with right-sided infarction.
Complete infarction, involving both the upper and
lower divisions, is often a catastrophic event (Heinsius et al.
1998) and, in addition to a profound hemiplegia, such a
‘malignant MCA infarction’ may also be accompanied by
stupor and vasogenic edema developing over the following
2–5 days may cause uncal or tentorial herniation with coma
and death (Hacke et al. 1996): in such cases, decompressive
hemicraniectomy may be life-saving.
ACA infarction, classically, produces a contralateral
hemiplegia and hemianesthesia preferentially affecting the
lower extremity (Critchley 1930); when the left hemisphere
is involved, a transcortical motor aphasia may also appear.
When the corpus callosum is infarcted, one may also see a
‘disconnection syndrome’ with left-sided, but not rightsided,
agraphia, tactile agnosia or apraxia, and, rarely, the
alien hand syndrome. In cases of bilateral infarction (e.g., as
may occur with an azygous ACA), paraplegia may occur, as
may abulia, a frontal lobe syndrome, or akinetic mutism.
PCA infarction typically causes a contralateral hemianopia
(Castaigne et al. 1973; Pessin et al. 1987). If the infarction
is on the left, one may also see alexia with agraphia,
visual agnosia, and, if the temporal lobe is involved, a delirium.
Infarctions on the right side that also involve the temporal
lobe may be accompanied by prosopagnosia, and, in some
cases a delirium (Medina et al. 1974). Bilateral infarction is
signaled by cortical blindness, which may or may not be
accompanied by Anton’s syndrome, with denial of the blindness.
In cases of bilateral infarction when both temporal
lobes are involved, patients may also be left with a
Korsakoff ’s syndrome. As described earlier, central branches
arise from the PCA (i.e., thalamoperforating, thalamogeniculate,
and posterior choroidal) and if these are also occluded,
the typical symptoms just described will be joined by the syndromes
peculiar to occlusion of these central branches, as
described below, under ‘lacunar syndromes’. Furthermore,
when some of the very small penetrating branches to the
mesencephalon are involved, there may be hemiparesis, oculomotor
disturbances, and abnormal movements.
Anterior choroidal artery infarction is marked by contralateral
hemiplegia and hemianopia (Helgason et al. 1986).
Importantly, however, there is no accompanying aphasia or
neglect, and generally no, or only transient, hemianesthesia,
and it is the absence of these symptoms that distinguishes
these infarctions from those that occur secondary to occlusion
of the MCA.
Basilar artery occlusion is often a catastrophic event
(Caplan 1979; von Campe et al. 2003). Involvement of the
basis pontis produces a quadriparesis, and involvement of
the midbrain will add diplopia.
Vertebral artery occlusion or occlusion of a posterior
inferior cerebellar artery (or occlusion of one of the perforating
branches of either of these arteries) may give rise to
the classic Wallenberg or ‘lateral medullary’ syndrome (Kim
2003; Sacco et al. 1993). Infarction of the lateral medulla typically
involves the following structures: inferior cerebellar
peduncle, spinothalamic tract, the spinal tract and nucleus
of the fifth cranial nerve, the nucleus ambiguus, vestibular
nuclei, and descending sympathetic fibers. Respectively, the
corresponding symptoms are: ipsilateral ataxia; contralateral
hemianesthesia of the extremities; ipsilateral anesthesia
of the face (which may be accompanied by pain); hoarseness
and dysphagia; nausea, vomiting, and vertigo; and an ipsilateral
Horner’s syndrome. Occlusion of one of the originating
branches of the anterior spinal artery may produce the
‘medial medullary’ syndrome (Kim et al. 1995). Here,
infarction of the pyramid and of the emerging fibers of the
twelfth cranial nerve give rise to an ipsilateral paresis of the
tongue and a contralateral hemiparesis.
Cerebellar artery occlusion, including the posterior
inferior, anterior inferior, and superior cerebellar arteries,
may cause vertigo, nausea, nystagmus, or ipsilateral ataxia.
Large infarctions, with attendant vasogenic edema, may,
by compressing the underlying brainstem, cause stupor or
coma, and in such cases emergent neurosurgical intervention
may be required (Jensen et al. 2005).
Low-flow (watershed) infarctions
Watershed infarctions typically present with more or less
atypical fragments of some of the large vessel syndromes.
Thus, ACA–MCA watershed infarcts involving the prefrontal
cortex and subjacent white matter may present with
brachial or crural paresis, and, when the left hemisphere is
involved one may see mutism, initially, which resolves into
a transcortical motor aphasia. MCA–PCA watershed
infarcts may present with hemianesthesia, hemianopia,
and, if the left hemisphere is involved, a transcortical sensory
aphasia. ACA–MCA infarcts involving the centrum
semiovale present with a variable mixture of either of the
foregoing syndromes. ‘Internal’ watershed infarcts in the
border zone between the MCA and lenticulostriate arteries
may present with hemiparesis with or without hemianesthesia
(Kumral et al. 2004).
Lacunar syndromes
Lacunes are small cavities, ranging in size from 1 to 20 mm,
which typically represent infarctions in the area of distribution
of one of the central or perforating branches described
earlier (Fisher 1965, 1982; Mohr 1982). Although the clinical
presentation of lacunar infarctions is quite varied,
depending on the location of the lacune (Arboix et al.
2006), certain presentations are quite distinctive and highly
suggestive of lacunar infarction. These ‘classic’ lacunar syndromes
include ‘pure motor stroke’, ‘ataxic hemiparesis’,
‘dysarthria-clumsy hand’, and ‘pure sensory stroke’.
Pure motor stroke, as the name suggests, is characterized
by a hemiparesis in the absence of sensory changes or other