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Pediatr Neurosurg 1990-91: 16:326-330

Ruptured Intracranial Aneurysm Presenting as
Cerebral Infarction in a Young Child
AM. Rojiania, K.J. Poskirt h, D.D. Cochranec. A.J. Macnabd. A7/. G. Normana
Departments of “Pathology, ’’Radiology. "Neurosurgery and ''Pediatrics, British Columbia's Children's Hospital and
University of British Columbia. Vancouver. B.C., Canada

Key Words. Cerebral aneurysm * Vasospasm • Infarction
Abstract. We describe a 15-month-old girl who presented with an acute hemiplegia. The sequence of events appears
to have been clinically silent subarachnoid hemorrhage, vasospasm, infarction and a second lethal hemorrhage 3 months
later. The old infarction was seen on computed tomography during her second illness. Autopsy confirmed the presence
of a recent rupture of an intracranial aneurysm and old hemorrhage. In addition there was an unusual fibroblastic pro­
liferation in the aneurysm wall. This case demonstrates that clinically silent subarachnoid hemorrhage, vasospasm and
infarction can occur as complications of aneurysms, even in very young children.

The frequency of congenital aneurysms in the pediatric
group ranges from 0.5 to 4.6% of aneurysms at all ages
11-5]. Congenital aneurysms in children differ from those
in adults in the following respects: a higher male:female
ratio: an increased number of giant aneurysms, and a
higher percentage of lesions in the posterior circulation
[6]. These lesions are rare and therefore infrequently con­
sidered in the differential diagnosis of subarachnoid
hemorrhage (SAH). These factors were compounded in
this case by an unusual presentation with right-sided
hemiplegia. We report unusual histopathologic features,
intense cellular proliferation and the presence of giant
cells in the aneurysm wall.

Case Report
Our patient first presented to the emergency department of a local
hospital at the age of 15 months with acute onset of painless, right hemi­
plegia. Investigations including computed tomography (CT) and elec­
troencephalography showed no cause for the hemiplegia and the differ­
ential diagnosis was either a metabolic phenomenon or a post-ictal epi­
sode. Over the next 2 months she regained almost normal function.
Retrospective review of the initial CT scan after examination of the

brain, disclosed decreased attenuation of the head of the caudate and
was interpreted as representing a recent infarction (fig. 1).
At the age of 18 months, while being breast fed, she suddenly threw
her head back, arched her hack, screamed and clasped her head as if in
severe pain. On arrival at the local hospital she was comatose and was
transferred to British Columbia's Children’s Hospital. On admission
she moved all limbs symmetrically, with diminished response to pain
and little spontaneous movement. Focal neurological signs were absent.
The child required assisted ventilation and was treated with anticon­
vulsants. Over the next few hours occasional seizures occurred and
approximately 12 h after the initial episode she deteriorated, becoming
rapidly comatose, unresponsive, with fixed, dilated pupils and died.
A CT scan done at the time of deterioration showed SAH with blood
in the left sylvian fissure, the posterior aspect of both lateral ventricles
and in the fourth ventricle. The basal cisterns were obliterated. Cerebral
edema with transtentorial herniation and possible infarction in the dis­
tribution of the left middle cerebral and both posterior cerebral arteries
was present. Two focal areas of decreased attenuation representing old
infarctions were identified on the left, in the head of the caudate nucleus
and putamen (fig. 2). Angiography was not performed as the child was
in extremis.

Pathological Findings
Diffuse SAH was present over the cerebral hemi­
sphere, more marked over the left frontal and anterior
temporal areas and within the sylvian fissure. A moderate

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Introduction

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Ruptured Aneurysm Presenting as Cerebral Infarction

both in the wall of the aneurysm and in the adjacent paren­
chyma. Other intracranial vessels were normal on gross
and microscopic examination. The left hemisphere con­
tained an old infarct in the head of the caudate and putamen which extended posteriorly to the anterior thalamus
and involved a small area of the internal capsule (fig. 6).
There was marked cerebral edema. The midbrain was
compressed laterally; cerebellar tonsillar and uncal her­
niation were marked. Acute anoxic-ischemic changes
were present, particularly in the cerebellum. Arteries else­
where in the body were normal on gross examination and
were not sectioned.
There was terminal bilateral bronchopneumonia with
aspiration.

Fig. 1. Axial contrast CT head scan performed on the initial admis­
sion to another hospital. The scan was initially read as normal. The head
of the caudate nucleus is of decreased attenuation (arrowhead), repre­
senting a recent infarct.

amount of blood lay over the base of the brain and ventral
surface of the brainstem. An 0.8-cm diameter aneurysm
arose from the left middle cerebral artery, 0.2 cm distal to
its bifurcation (fig. 3). It was ovoid and contained clotted
blood. It was attached to the underlying vessel by a broad
neck. Microscopic examination of the aneurysm showed
that it had a relatively thick wall on one side and
contained a fresh blood clot and recent thrombus. Mas­
son’s trichrome and Verhoeff van Gieson elastic stains
showed a small segment of normal arterial wall, and a
much larger abnormal component with a dilated and
expanded aneurysm wall with a sudden, sharp decrease in
the smooth muscle of the media and an absence of elastic
lamina (fig. 4). The intimal surface of the aneurysm near
the neck showed marked proliferation of fibroblasts.
Within this area of proliferation there were occasional
multinucleate giant cells (fig. 5). There was hemosiderin
within the macrophages and in the extracellular space.

This case illustrates a number of unusual features. Our
patient was only 15 months old when she had her first
symptoms. Ruptured intracranial aneurysms (RIA) are a
rare cause of SAH in young children, with pediatric cases
ranging from less than 0.5 to 4.6% [1-5]. A recent autopsy
study of 133 patients with ruptured aneurysms revealed no
cases younger than 10 years and only 4 cases in the 10- to
19-year-old group [71. Crompton [8] reported 41 of 6,368
cases of RIA in the 1- to 19-year age group. The incidence
of aneurysms in very young children is even more infre­
quent. Patel and Richardson [2], in their study of 58 pa­
tients in the first 2 decades of life, reported no cases in the
0- to 7-year age group, while another series [5], reviewing
intracranial aneurysms in 43 children and adolescents,
describes only 1 child below the age of 4 years.
Children rarely present with signs and symptoms di­
rectly referable to an aneurysm; only when the aneurysm
ruptures is medical attention sought [9]. The symptoms
are those of a SAH, and the first consideration is hemorr­
hage from an arteriovenous malformation. Ostergaard and
Voldby [5] reported that 70% of their cases presented with
signs and symptoms typical of SAH. These included
intense headache and meningism. Of the remaining cases,
4 had no signs of SAH, 3 presenting with oculomotor
paresis and 1 a left hemiplegia. Our case had an atypical
presentation, with a right hemiplegia and no clinical or
radiologic evidence of SAH. Initially no cause for the
hemiplegia could be identified, but a retrospective review
of the first CT scan showed early focal infarction in the
left basal ganglia. This was confirmed at autopsy. The
importance of missed, minor bleeding episodes leading to
vasospasm has also been emphasized [10]. Cerebral vaso-

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Discussion

Rojiani/Poskitt/Cochrane/Macnab/Norman

Fig. 2. a Axial CT head scan without contrast, obtained at the time
of the second admission to hospital. The slice was obtained at the level
of the inferior aspect of the sylvian fissures and documents the presence
of subarachnoid blood within the left sylvian fissure. The basal cisterns
are also obliterated, b Higher slice from the axial CT scan documenting

evidence of old infarctions involving the head of the caudate nucleus on
the left and part of the internal capsule (arrow). There are linear areas of
increased attenuation within the depths of the sylvian fissure, indicating
subarachnoid hemorrhage.

spasm, clinical or radiographic, is common following
SAH from a R1A. Its incidence varies from 30 to 70%,
varying significantly with the time of angiography and the
severity ofSAH [11]. Fisheretal. [ 12] showeda50% inci­
dence of delayed (after day 3) cerebral ischemia and neu­
rologic deficit associated with vasospasm in RIA. At
autopsy, cerebral infarctions have been reported in 60% of
adults following RIA [8|. The role of cerebral vasospasm
in the outcome of RIA was assessed in 43 patients, 19
years or younger, with verified intracranial saccular
aneurysms. Vasospasm was demonstrated in 53% of 19
patients who had angiographic studies performed after the
3rd day and between the 1st and 2nd week after SAH, the
period most frequently associated with the development
of vasospasm. None of the patients who developed vaso­

spasm had an increased mortality and no cerebral infarc­
tion was seen at autopsy ]5|. In another study 7 of 54 cases
under the age of 20 years showed radiographic vaso­
spasm. Autopsies on 4 of these 7 cases showed no cerebral
infarctions, despite the presence of severe radiographic
vasospasm in 2 autopsied cases [2], A possible explana­
tion is the increased resilience of childhood arteries com­
pared to adults, although no evidence is provided for this
hypothesis [13]. We feel that this child had a silent, minor
bleeding episode which resulted in focal cerebral vaso­
spasm of the perforating branches of the middle cerebral
artery. This caused an infarction which subsequently pre­
sented as hemiplegia. This hypothesis is supported by evi­
dence of an old hemorrhage in the wall of the aneurysm
and adjacent parenchyma, and autopsy confirmation of the

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328

Ruptured Aneurysm Presenting as Cerebral Infarction

329

Fig. 5. Fibroblastic proliferation in intitna showing occasional giant
cells (arrows). HE. Original magnification X 100.

Fig. 3. A single aneurysm is seen, arising from the left middle cere­
bral artery, with adjacent clotted blood. The frontal tip of the left tem­
poral lobe has been resected to permit visualization of the aneurysm.

Fig. 4. Section through the neck and body of the aneurysm showing
normal arterial wall with lamina (arrow) and expanded aneurysm wall
with intimal thickening and absence of elastic lamina and smooth
muscle. Verhoeff van Gieson stain. Original magnification x20.

old infarction. In the absence of typical signs of SAH and
angiography for detection of the aneurysm or the pre­
sumed vasospasm, interpretation of this child’s clinical
presentation with hemiplegia was difficult.
An unusual pathological feature of this case is the
intense fibroblastic reaction with occasional giant cells
seen in the intima of the vessel. Histopathologic studies of
cerebral blood vessels in vasospasm related to SAH have
shown changes including intimal swelling and prolifera­
tion. as well as a variety of other histopathologic features
consistent with complement-dependent immune reactions
[14-16]. Intimal proliferation has previously been de­
scribed in an 11-month-old infant who also showed fibro-

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Fig. 6. Old infarction involving caudate, putamen and internal cap­
sule (arrow). Subarachnoid hemorrhage is also evident in this coronal
section through the frontal lobes.

Rojiani/Poskitt/Cochrane/Macnab/Norman

muscular hyperplasia of the renal arteries [17]. While no
gross abnormalities were identified in other extracranial
vessels examined in our case, both cases represent
aneurysms of the ‘congenital type', with an absence of
elastic lamina and smooth muscle within the media. Al­
though the giant cells seen in this case may indicate an
inflammatory process, such as some form of vasculitis,
other intracranial vessels examined were histologically
normal. The precise etiopathogenesis of this proliferative
reaction is uncertain.
In conclusion, we describe a young child who suffered
a clinically silent early hemorrhage, presumed cerebral
vasospasm and resulting cerebral infarction, a rare presen­
tation for a ruptured intracranial aneurysm in early child­
hood.

Acknowledgement
We thank coroner Dennis McSweeney for permission to publish
this case.

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Dr. M.G. Norman
Department of Pathology
British Columbia’s Children's Hospital
4480 Oak Street
Vancouver, B.C. V6H 3V4 (Canada)

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