CASE REPORT
Nagoya J. Med. Sci. 85. 343–349, 2023
doi:10.18999/nagjms.85.2.343

A rare pure intraventricular hemorrhage caused by ruptured
internal carotid artery-anterior choroidal artery aneurysm:
a case report and literature review
Yota Suzuki1, Yoshiki Hanaoka1,2, Yuki Inomata1, Takaaki Kamijo2,
Yu Fujii1, Toshihiro Ogiwara1 and Tetsuyoshi Horiuchi1,21Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan2
Neuroendovascular Therapy Center, Shinshu University Hospital, Matsumoto, Japan

ABSTRACT
Although intraventricular hemorrhage (IVH) frequently develops secondary to intraparenchymal or
subarachnoid hemorrhage, pure IVH—non-traumatic spontaneous intracranial hemorrhage confined to the
cerebral ventricular system—is rare. Moreover, pure IVH caused by ruptured proximal aneurysm is anextremely rare but life-threatening condition. Herein, we present a case of pure IVH due to a ruptured
internal carotid artery -anterior choroidal artery (ICA-AChA) aneurysm and review related literature. A
77-year-old man presenting with altered mental status was hospitalized due to a massive pure IVH withventriculomegaly. The patient was conservatively managed because his consciousness level improved. On
the following day, computed tomography angiography revealed a right ICA-AChA aneurysm embeddedin the temporal lobe adjacent to the anterior part of the inferior horn of the lateral ventricle, which wasconsistent with the hemorrhagic origin. Coil embolization of the aneurysm was successfully performed,
and the postprocedural course was uneventful. To date, only a few cases have described pure IVH caused
by a ruptured proximal aneurysm. If the ruptured proximal aneurysm remains unnoticed, catastrophic
rehemorrhage may occur. Aneurysm obliteration should precede the treatment of acute hydrocephalus.
Neurosurgeons/neurointerventionalists must be aware about pure IVH caused by a ruptured proximal
aneurysm even if it rarely occurs.
Keywords: acute hydrocephalus, isolated intraventricular hemorrhage, primary intraventricular hemorrhage,
ruptured cerebral aneurysm, solitary intraventricular hemorrhage
Abbreviations:
AChA: anterior choroidal artery
ICA: internal carotid artery
IVH: intraventricular hemorrhage
This is an Open Access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
License. To view the details of this license, please visit (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Received: February 22, 2022; accepted: April 25, 2022
Corresponding Author: Yoshiki Hanaoka, MD, PhD
Department of Neurosurgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621,
Japan
Tel: +81-263-37-2690, E-mail: hanaoka@shinshu-u.ac.jp343

Yota Suzuki et al

INTRODUCTION
Ruptured cerebral aneurysm is life-threatening and requires urgent medical attention. It commonly causes subarachnoid hemorrhage (SAH), which is occasionally associated with intraparenchymal hemorrhage (IPH), intraventricular hemorrhage (IVH), or subdural hematoma. However,extremely rare cases of pure IVH (isolated, primary, or solitary IVH), that is, non-traumatic
spontaneous intracranial hemorrhage in the cerebral ventricular system without any evidence of
IPH or SAH that is caused by ruptured proximal aneurysms such as supraclinoid internal carotid
artery (ICA), anterior communicating artery (ACoA), and basilar artery aneurysms, have beenreported.1-8 In such cases, the ruptured cerebral aneurysm can be overlooked, potentially leading
to fatal rebleeding. Herein, we present a rare case of pure IVH due to a ruptured ICA-anteriorchoroidal artery (AChA) aneurysm and a review of related literature.

CASE REPORT
A 77-year-old man with altered mental status (Glasgow Coma Scale [GCS] score, E2V2M5)
presented to a nearby hospital. He had no history of hypertension, dyslipidemia, diabetes mellitus, stroke, and smoking or alcohol abuse. On admission (day 0), computed tomography (CT)revealed a massive pure IVH with ventriculomegaly but no SAH (Fig. 1). Owing to the patient’s
gradually improving consciousness (GCS score, E3V4M6), conservative treatment was applied.
On day 1, CT angiography (CTA) disclosed a right ICA-AChA aneurysm (11 mm) embeddedin the temporal lobe contiguous to the anterior part of the inferior horn of the lateral ventricle(Fig. 2). The hematoma distribution indicated that the ICA-AChA aneurysm was compatible
with the hemorrhagic origin. On the same day, the patient was transferred to our institution
for emergent endovascular treatment. Under general anesthesia, a 6F Simmons guiding sheath(6F Axcelguide Stiff-J-1, 90 cm; Medikit, Tokyo, Japan) was introduced into the right common
carotid artery via a right transradial approach.9-12 After a 6F intermediate catheter (6F SOFIA,
115 cm; MicroVention-Terumo, Aliso Viejo, California, USA) was delivered into the ICA petrous
segment, coil embolization of the aneurysm was performed using the double-catheter technique.
Aneurysm obliteration and AChA patency were confirmed on postprocedural angiography (Fig. 3).

Fig. 1 Head computed tomography (CT) images on admission
CT shows a massive pure intraventricular hemorrhage with ventriculomegaly but no evidence of subarachnoid
hemorrhage.
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Pure IVH caused by ruptured ICA aneurysm

Fig. 2

Preprocedural computed tomography angiography (CTA) source image (left) andthree-dimensional CTA image (right)
The CTA source image demonstrates a right internal carotid artery-anterior choroidal artery (ICA-AChA)
aneurysm (arrows) compatible with a hemorrhagic origin. The ICA-AChA aneurysm projected posterolaterally
and is embedded in the temporal lobe adjacent to the anterior part of the inferior horn of the lateral ventricle.

Fig. 3

Preprocedural three-dimensional rotational angiography (3DRA) (A)/angiography (B) andpostprocedural angiography images (C)Fig. 3A: Right anterior oblique view of the preprocedural 3DRA image showing a right internal carotid arteryanterior choroidal artery (ICA-AChA) aneurysm (arrow). The right AChA (arrowheads) originates fromthe aneurysm neck.
Fig. 3B: Right anterior oblique view of the preprocedural angiography image showing the right ICA-AChA
aneurysm (arrow) and right AChA (arrowheads).
Fig. 3C: Right anterior oblique view of the postprocedural angiography image confirming the successful obliteration of the ICA-AChA aneurysm and right AChA patency (arrowheads).

The postprocedural course was uneventful. The patient’s consciousness gradually recovered. On
day 11 and day 18, follow-up magnetic resonance angiography revealed no evidence of cerebral
infarction and delayed cerebral vasospasm. On day 21, satisfactory aneurysm obliteration was
confirmed on follow-up angiography. On day 36, magnetic resonance imaging revealed that the
IVH was completely washed out without ventriculomegaly (Fig. 4). On day 39, the patient wasdischarged home, with clear consciousness.
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Yota Suzuki et al

Fig. 4

Postprocedural fluid-attenuated inversion recovery (FLAIR) (A) and magnetic resonanceangiography (MRA) maximum intensity projection (MIP) images (B) and
MRA source image (C) 37 days after onset of hemorrhage
Fig. 4A: FLAIR images showing the intraventricular hemorrhage completely washed out with no evidence ofischemic stroke and ventriculomegaly.
Fig. 4B, 4C: Follow-up MRA MIP and source images showing no evidence of recanalization of the treatedaneurysm (arrows).

DISCUSSION
IVH frequently develops secondary to IPH or SAH. However, pure IVH is rare, accounting for
0.31% and ≤3% of all stroke and intracranial hemorrhage cases.2,5 Initial manifestations include
headache (69%), altered mental status (66%), and nausea/vomiting (53%).2 The overall in-hospitalmortality was 39%. High patient age, low initial GCS score, large amount of IVH, and acutehydrocephalus are poor independent prognostic predictors.2,5 While Moyamoya disease, duralarteriovenous fistulas, intraventricular/paraventricular cavernous malformations, or intraventricular/paraventricular tumors rarely cause pure IVH, cerebral aneurysms and arteriovenous malformations
are the most common vascular causes.2,13 Pure IVH caused by ruptured cerebral aneurysm has
high morbidity and mortality.6 The aneurysms were reported to be predominantly peripheral,
including intraventricular aneurysms (eg, distal AChA aneurysm, medial posterior choroidal arteryaneurysm, lateral posterior choroidal artery aneurysm, lenticulostriate artery aneurysm, distal
posterior inferior cerebellar artery aneurysm and distal superior cerebellar artery aneurysm) whichusually are very small and occur secondary to arteriovenous malformation, Moyamoya disease,
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NA

29/F

Flint et al, (2008)

Prasad et al,3 (2009)

Nakagawa et al,(2014)

Nagoya J. Med. Sci. 85. 343–349, 2023

347

53/F

58/M

70/M

77/M

Anagnostopoulos etal,6 (2019)

Kim et al,7 (2019)

Oberman et al,8(2020)

Present case

Yes
Yes

Altered mental status(stupor)Yes

Headache/alteredmental status(disorientation)

Headache/nausea

Yes

Altered mental status(coma)NA

Yes

Headache/alteredmental status(confusion)

NA

No

Headache/vomiting

NA

Yes

Altered mental status(coma)

NA

Acutehydrocephalus

CTA

CTA

CTA

Angiography

NA

CTA

CTA

Angiography

Angiography

Modality

Diagnosis

2

1

1

3

NA

1

1

NA

1

PAD

11

7

7

NA

NA

NA

NA

NA

24

Size
(mm)

ICA-AChA

ACoA

ICA-AChA

ICA-PCoAACoA

ICA-PCoAICA-PCoA

Pericallosal

BA tipLocation

Ruptured aneurysm

Postero-lateral

Antero-superior

Postero-lateral

Postero-lateralNA

LateralLateralNA

NA

Projection

Summary of case reports of pure IVH caused by ruptured proximal aneurysms

Initial manifestation

AChA: anterior choroidal artery
ACoA: anterior communicating artery
BA: basilar artery
CTA: computed tomography angiography
EVD: external ventricular drainage
F: female
GOS: Glasgow Outcome Scale
ICA: internal carotid artery
IVH: intraventricular hemorrhage
LD: lumbar drainage
M: maleNA: not available
PAD: post-admission day
PCoA: posterior communicating arteryNA

Lee et al,5 (2017)

4

45/F

50/M

2

Thai et al, (2005)

1

Age(years)/sex

Table 1

No

NA

No

NA

NA

NA

NA

NA

No

Cerebralvasospasm

5

1

Clipping
followed by
EVD
Coiling

4

5

NA

5

5

NA

2

Discharge
GOS
score

Coiling followed by LD

EVD followedby coilingNA

Coiling
followed by
EVD

CoilingNA

Coiling

Treatment

Pure IVH caused by ruptured ICA aneurysm

doi:10.18999/nagjms.85.2.343

Yota Suzuki et al

infection, or head trauma.2,14,15 As they occasionally disappear spontaneously, conservative treatment may be used for ruptured intraventricular aneurysms if there is no possible treatment.14 By
contrast, pure IVH caused by ruptured proximal aneurysms is extremely rare, with only 9 cases,
including our case, reported so far (Table 1).1-8 Such aneurysms have a rebleeding risk, which
can be potentially devastating and fatal. The case reported by Oberman et al was diagnosed as
pure IVH caused by a ruptured ACoA aneurysm on day 0.8 On day 2, the patient’s consciousness deteriorated before treatment, which indicated rebleeding of the aneurysm. The patient dieddespite aneurysm clipping and external ventricular drainage. To prevent catastrophic rebleeding,
the ruptured cerebral aneurysm must be correctly identified and treated immediately. The reported
aneurysms were ≥7 mm (range, 7–24 mm) and located in the ICA-posterior communicating artery(PCoA; n = 3), ICA-AChA (n = 2), ACoA (n = 2), pericallosal artery (n = 1), and basilar
artery (n = 1; Table 1). Pure IVH can occur theoretically if the aneurysm protrudes into the
cerebral ventricular system. In clinical practice, all ICA aneurysms (n = 5) were embedded in
the temporal lobe adjacent to the anterior part of the inferior horn of the lateral ventricle (Table
1). Diagnosis was performed using angiography (n = 3) and CTA (n = 5; Table 1). Angiography
is a promising modality for identifying potentially treatable causes of pure IVH, including verysmall intraventricular aneurysms.2 Considering aneurysm size (≥7 mm), CTA will be a usefuldiagnostic modality for pure IVH caused by ruptured proximal aneurysm because it can detect
the anatomical relationships between the aneurysm, cerebral ventricular system, and hematoma
distribution. Acute hydrocephalus occurred in 6 cases and was treated conservatively (n = 2),
with coiling/clipping followed by cerebrospinal fluid drainage (n = 3), and with cerebrospinal
fluid drainage followed by coiling (n = 1; Table 1). In another reported case, external ventriculardrainage was used for acute hydrocephalus associated with pure IVH before identification of thecausative vascular lesion (day 0).6 Fortunately, aneurysm coiling was achieved without rebleeding
after detection of the ruptured ICA-PCoA aneurysm on day 2. For intracranial pressure control
and/or hematoma removal, external ventricular drainage, and/or endoscopic surgery should beconsidered urgently for acute hydrocephalus associated with IVH, especially in patients withdecreased consciousness,2,16,17 but these could cause rebleeding from the ruptured aneurysm,18
which can be a pitfall in patients with pure IVH caused by ruptured proximal aneurysms. In
patients with pure IVH, vascular imaging is mandatory, not optional. Surgical/endovascular treatment for ruptured aneurysm should precede treatment for acute hydrocephalus. Neurosurgeons/neurointerventionalists must be knowledgeable about pure IVH caused by a ruptured proximal
aneurysm even if it rarely occurs.

AUTHOR CONTRIBUTIONYS and YH contributed equally as first authors to this work.

CONFLICTS OF INTEREST
The authors have no conflicts of interest to disclose.

ETHICS APPROVALThis study was performed in accordance with the ethical standards of the 1964 Declarationof Helsinki and its later amendments.
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