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Brain & Development 1994; 16:233-7

Case Report

A case of cerebral aneurysm associated
with complex partial seizures
Katsuji Tanaka a, MD, Ken Hirayama a, MD, PhD, Hideji Hattori a MD, PhD,
Osamu Matsuoka a, MD, Hiroaki Sakamoto b, MD, PhD, Akira Hakuba b, MD, PhD,
Ryosuke Murata a, MD, PhD

We report a 20-month-old girl with an unruptured aneurysm of the middle cerebral artery. The initial sign was
complex partial seizures. Magnetic resonance angiography showed an aneurysm of the right middle cerebral artery.
Cerebral angiography confirmed the presence of a saccular aneurysm. After 3 months, the aneurysm spontaneously
thrombosed without neurological deficit. The seizures were controlled by anti-convulsants. The aneurysm was
probably near the focus of the complex partial seizures. This is a rare case of a childhood cerebral artery aneurysm
that first manifested itself by complex partial seizures.

Key words." Cerebral aneurysm; Cerebral vascular anomaly; Epileptogenic focus; Complex partial seizure in infancy;
Magnetic resonance angiography

1. INTRODUCTION
Cerebral aneurysms are rare in early childhood [1].
One common result of an aneurysm in both adults and
children is subarachnoid hemorrhage, and epilepsy
from this cause is rare. We report a patient with an
unruptured aneurysm of the right middle cerebral
artery (MCA) who presented with complex partial
seizures. The aneurysm was detected by magnetic resonance angiography (MRA), and it thrombosed spontaneously, which is rare in childhood [2].

Departmentsof a Pediatrics and b Neurosurgery, Osaka City University Medical School, Osaka, Japan
Received 7 October 1993; accepted 16 January 1994
Correspondence address: Dr. K. Tanaka, Department of Pediatrics,
Osaka City University Medical School, 1-5-7 Asahi-machi, Abeno-ku,
Osaka 545, Japan. Fax: (81) (6) 646-5862.
0387-7604/94/$07.00 © 1994 ElsevierScience B.V. Allrightsresewed
SSDI 0 3 8 7 - 7 6 0 4 ( 9 4 ) 0 0 0 1 7 - R

2. CASE REPORT

A 20-month-old girl was hospitalized at our hospital
for treatment of seizures. The first episode, in which
the patient suddenly stared to the left side for about 1
min with impairment of consciousness, occurred when
she was 16 months old. The seizures reoccurred every
few days. She was first hospitalized elsewhere. Results
of electroencephalography ( E E G ) are shown in Fig. 1.
There were spikes and slow waves in the right occipital
area (Fig. 1A). Computed tomography (CT) of the
brain revealed a high-density lesion in the right temporal lobe (Fig. 2A). Complex partial seizures were diagnosed from the E E G findings and seizure type. Phenytoin and valproate did not control the seizures.
The patient was referred to our hospital for further
evaluation and therapy. The family history and perinatal history were negative. Development was slightly
delayed; she first walked alone at the age of 18 months.
There were no other neurological abnormalities. The

IL Tanaka et al. /Brain & Decelopment 1994, 16:233 7

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1. A :

temporal

EEG at 16 months of age. T h e spikes and waves are in the right occipital area. B,C: EEG on admission. The sharp wave is in the right
area and the spikes are in the right central area.

laboratory data were normal. EEG showed focal spikes
and sharp waves in the right central and temporal
areas (Fig. 1B,C). Contrast-enhanced CT showed enhancement of the lesion (Fig. 2B). T:weighted magnetic resonance imaging (MRI) showed a high-signal

area surrounding a signal void in the right hippocampus (Fig. 3A). T:weighted images showed a signal void
with a high-signal area inside (Fig. 3B). Because these
findings suggested that there was a vascular disorder,
probably a partially thrombosed aneurysm, MRA was

Fig. 2. A: plain C T scan at 16 months of age. T h e r e is a high-density area in the right temporal lobe. B: contrast-enhanced C T scan at 20 months.
The right temporal lesion is enhanced.

K. Tanaka et al. /Brain & Development 1994; 16." 233-7

done. M R A showed a n a n e u r y s m in the M~ p o r t i o n of
the right M C A (Fig. 3C). This a n e u r y s m was also
revealed by c e r e b r a l angiography, which showed a sac-

235

cular a n e u r y s m of the right M C A m e a s u r i n g 15 × 8
m m (Fig. 3D). T h e r e was stenosis of the right M C A
proximal to the a n e u r y s m .

Fig. 3. Initial MRI, cerebral angiography, and MRA. A: the Tl-weighted image shows a signal void surrounded by a high-signal area in the right
hippocampus. B: the T2-weighted image shows a signal void containing a smaller high-signal area. C: MRA shows a large aneurysm in the M~
portion of the right MCA. D: digital subtraction angiography done during the first admission shows a large saccular aneurysm of the right MCA
(arrow). The parent artery is narrow.

23~

K. Tanaka et al. / Brain & Del~elopment 1994," 16." 233-7

The seizures were controlled by valproate, diazepam, and carbamazepine. Three months later, the
patient was re-admitted because surgical treatment was

planned. MR1 and M R A were done again. The thrombosed aneurysm was visible, but the right M C A was not
(Fig. 4 A - C ) . Cerebral angiography (Fig. 4D) showed

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Fig. 4. MRI, MRA, and cerebral angiography on second admission. A: the Ti-weighted image shows a high-signal area in the right hippocampal
region. B: the T2-weighted image shows a signal void containing a smaller high-signal area. C: MRA shows that the aneurysm had thrombosed,
but that the right MCA bad not. D: digital subtraction angiography. The trunk of the right MCA and the aneurysm are not visible.

K. Tanaka et al. /Brain & Development 1994; 16. 233-7

occlusion of the right MCA; the aneurysm was not
seen. Through collateral vessels, there was retrograde
filling of the area distal to the MCA occlusion.
[123I]Iodoamphetamine single-photon emission tomography showed decreased cerebral blood flow in the
right temporoparietal region. There was no neurologic
deficit.

3. DISCUSSION
The MCA is frequently the affected artery in children with cerebral aneurysm [1]. The signs and symptoms of unruptured aneurysms can include headache,
cranial nerve palsies, and other neurologic deficits.
Epilepsy is an initial manifestation of unruptured
aneurysms in adults [3-6], but to the best of our
knowledge, there are few reports of epilepsy in this
condition in early childhood [1]. Aneurysms associated
with epilepsy are usually large, and are often of the
MCA [3-6]. The seizure type is usually of complex
partial seizures [3-6], although the type depends on
the location of the aneurysm.
In this case, it seemed that the aneurysm caused the
epilepsy. Complex partial seizures are uncommon in
children under 3 years of age [7,8]. Etiological factors
associated with complex partial seizures are birth asphyxia, congenital infections, neoplasms, arteriovenous
malformations, and congenital cerebral anomalies.
Aneurysm is a very rare cause of complex partial
seizures [9]. It is not known how an aneurysm causes
epilepsy. At least three mechanisms have been proposed: compression of the adjacent cortex by the
aneurysm [4], subclinical hemorrhage from the
aneurysm resulting in tissue damage with later development of an epileptic focus [4-6], and ischemia secondary to embolization by the thrombus from an unruptured thrombosed aneurysm [6]. Our patient had
complex partial seizures and the E E G findings were of
focal spikes and slow waves from the occipital to the
temporal area in the right hemisphere. The aneurysm
was adjacent to the cortex of the right medial temporal
lobe, and it was large. These factors may have been
associated with the seizures.
During the first admission, cerebral angiography
showed stenosis of the right MCA proximal to the
partially thrombosed aneurysm. Occlusion of the par-

237

ent artery of an aneurysm is very rare [10]. That the
patient had no neurological deficit suggests that the
occlusion progressed slowly. Compression of the parent
artery by the aneurysm itself and the propagation of
thrombosis from the aneurysm may occlude the parent
artery [10]. We assume that compression of the parent
artery by the aneurysm slowed the blood flow, and that
the thrombus was propagated from the thrombosed
aneurysm into the parent artery.
Treatment for epilepsy caused by an unruptured
aneurysm includes anti-convulsant therapy and surgery.
Surgery can prevent subarachnoid hemorrhage and alleviate seizures. For epilepsy, an aneurysmectomy is
more effective than wrapping of the aneurysmal walls
[4]. In our patient, there was little risk of subarachnoid
hemorrhage, because the aneurysm and parent artery
had thrombosed.

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