The Journal of Emergency Medicine, Vol. -, No. -, pp. 1–4, 2017
Ó 2017 Elsevier Inc. All rights reserved.
0736-4679/$ - see front matter

http://dx.doi.org/10.1016/j.jemermed.2017.06.030

Clinical
Communications: Adult
SPONTANEOUS SUBCLAVIAN ARTERY DISSECTION CAUSING ISCHEMIA OF
THE MEDULLA OBLONGATA AND CEREBELLUM
Naoto Nagino, MD,* Hiraku Funakoshi, MD, MPH, PHD,* Takashi Shiga, MD, MPH,* and Kuniyasu Saigusa, MD, PHD†
*Department of Emergency and Critical Care Medicine, Tokyobay Urayasu Ichikawa Medical Center, Urayasu-shi, Chiba, Japan and
†Department of Neurosurgery, Tokyobay Urayasu Ichikawa Medical Center, Urayasu-shi, Chiba, Japan
Reprint Address: Naoto Nagino, MD, Department of Emergency and Critical Care Medicine, Tokyobay Urayasu Ichikawa Medical Center,
3-4-32 Todaijima, Urayasu-shi, Chiba, 279-0001, Japan

, Abstract—Background: Spontaneous subclavian artery
dissection is a rare etiology. Spontaneous artery dissection
causing brain ischemia is rare in all ischemic strokes.
However, in young to middle-aged patients with brain
ischemia, spontaneous carotid or vertebral artery dissection
causing ischemic stroke accounts for 10–25%. Case Report:
A 58-year-old man with a history of hypertension presented
to the Emergency Department with a sudden onset of leftarm paresthesia and numbness followed by symptoms of
vertigo and vomiting. A neurological examination showed
left-arm paresthesia, horizontal-rotational nystagmus, and
left-side dysmetria according to a finger-to-nose test.
Contrast-enhanced computed tomography showed left subclavian artery dissection. Diffusion-weighted imaging
demonstrated hyperintensity in the left medulla oblongata
and inferior part of the cerebellum. Why Should an Emergency Physician Be Aware of This?: Spontaneous artery
dissection is an important etiology of ischemic stroke among
young patients. Cervical magnetic resonance angiography is
the gold standard for the diagnosis of arterial dissection.
Cervical disc disease is a common etiology in a patient
with neck and shoulder pain without cause or neurologic
symptoms, when cervical MRI is negative, however, spontaneous subclavian artery dissection should be considered in
the differential diagnosis when a patient, especially in a
case of younger patient, presents with acute new-onset

neck and shoulder pain followed by the onset of neurological
symptoms. Ó 2017 Elsevier Inc. All rights reserved.
, Keywords—brain infarction; subclavian artery dissection;
vertebral artery dissection

INTRODUCTION
Subclavian artery dissection (SAD) is a rare condition
usually associated with an anomalous aortic arch, trauma,
or cardiac catheterization (1–3). Spontaneous arterial
dissection accounts for 2% of all ischemic strokes (4).
However, it is a major cause of brain ischemia in young
to middle-aged patients without any risk factors associated
with atherosclerosis (4,5).
CASE REPORT
A 58-year-old man presented to our Emergency Department via ambulance complaining of sudden left-arm
paresthesia and numbness after the onset of left shoulder and neck pain. Shortly after the onset of paresthesia, he started to have vertigo and vomiting. He
denied chest pain. On examination, he was alert and
oriented. His blood pressure was 150/66 mm Hg in
the right arm and 134/79 mm Hg in the left arm. His
pulse was 72 beats/min. The left radial pulse was
slightly weaker than the right. Left-arm paresthesia,

Informed consent was obtained from the patient for publication of this case report and accompanying images.

RECEIVED: 14 November 2016; FINAL SUBMISSION RECEIVED: 2 March 2017;
ACCEPTED: 28 June 2017
1

2

horizontal-rotational nystagmus, and left-side dysmetria, according to a finger-to-nose test, were observed.
The remainder of the examination was unremarkable.
He was a smoker with a 68-pack-year smoking history.
There was no history of trauma or neck manipulation.
Electrocardiography displayed a normal sinus rhythm
without any significant ST-T changes. Magnetic resonance imaging (MRI) of the brain 3 h after the onset
of his symptoms demonstrated normal findings
(Figure 1). Magnetic resonance angiography (MRA)
of the head and cervical region (not including aortic
arch) revealed the left vertebral artery to not be visible
(Figure 2). Subsequently, we ordered a contrastenhanced computed tomography scan of the chest and
neck to rule out the aortic dissection, which was a
possible cause of the pain and paresthesia at the left
upper extremity. Computed tomography showed a
dissection flap in the first part of the left subclavian
artery at the intersection with the left vertebral artery,
which was occluded (Figure 3A and B). A neurologist
was consulted thereafter. We did not administer
tissue plasminogen activator, and admitted him to the
general ward for follow-up. On the second hospital
day, his initial symptoms improved slightly; however,
he reported a decreased left-side facial sensation, which
had not been observed at the time of admission. His
new symptoms were not observed on physical
examination. We decided to follow up his symptoms.
A second MRI study was planned on the next
day. On the third hospital day, the left neck and
shoulder pain suddenly recurred in the early morning.

N. Nagino et al.

Figure 2. Magnetic resonance angiogram of the head and
neck 3 h after the onset of the patient’s symptoms shows
an occluded left vertebral artery.

On examination, there were decreased pain and
temperature sensations in the right-side trunk and limbs
and the left side of the face, and the pulse in the left
arm was weaker than in the right. Repeated MRI, obtained about 42 h after the onset, revealed a restricted
diffusion area in the left medulla oblongata and the
inferior part of the cerebellum (Figures 4 and 5). We
considered that those symptoms were likely to be the
result of an expanded dissection lumen. The
cardiologist decided that no intravascular intervention
or thrombolysis was needed. Blood pressure control
without antithrombotic therapy was recommended.
Continuous careful evaluation and monitoring of the
patient’s blood pressure are essential in the case of
arterial dissection. At 1 month after admission, he
was discharged with slightly decreased pain and
temperature sensations in the right-side trunk and
limbs, which completely disappeared when examined
at both 1 and 3 months after discharge.
DISCUSSION

Figure 1. A diffusion-weighted image 3 h after the onset of
the patient’s symptoms is normal.

This cerebrovascular accident was caused by left
spontaneous SAD into the left vertebral artery, which
reduced the vertebral artery flow, resulting in ischemia
of the medulla oblongata and cerebellum. The risks of
atherosclerosis, which included current smoking and
hypertension in this case, could have contributed to
the narrow arteries of the brain. Flow-limiting stenosis
or hypoplasia could have been present in the left vertebral artery, which was the risk of posterior circulation

Spontaneous Subclavian Artery Dissection

3

Figure 3. (A,B) A contrast-enhanced computed tomography scan shows the presence of a dissection flap in the first part of the
left subclavian artery (arrow) at the origin of the left vertebral artery.

ischemic stroke (6,7). We therefore hypothesized
the pathophysiology of this case. In terms of other
possible pathophysiologies, we also considered arteryto-artery embolic ischemic stroke. However, given his
clinical findings as well as the radiological findings,
we concluded the etiology of this case to be left spontaneous SAD.
SAD causing brain ischemia is rare in all ischemic
strokes (4). However, in young to middle-aged patients
with brain ischemia, spontaneous carotid or vertebral
artery dissection causing ischemic stroke account for
10–25% (4,5). Cervical MRA is the gold standard for

the diagnosis of arterial dissection when brain ischemia
within the posterior circulation is suspected. Previous
reports indicate that ischemic stroke is sometimes
caused by arterial dissection proximal to the vertebral
artery, as was seen in this case (2,3,8,9). Thus, when
ischemic stroke caused by dissection is suspected, it is
noted to evaluate from intracranial to subclavian artery
for establishing the diagnosis. Particularly in a case of a
younger patient, however, it is important to consider
that spontaneous SAD can be the underlying cause in
patients with acute new-onset neck and shoulder pain
followed by neurological symptoms.

Figure 4. A diffusion-weighted image repeated on the third
hospital day shows high intensity, indicating acute infarction
of the medulla oblongata and cerebellum.

Figure 5. Repeat magnetic resonance angiogram of the head
and neck on the third hospital day shows no significant
change in the occluded left vertebral artery.

4

WHY SHOULD AN EMERGENCY PHYSICIAN BE
AWARE OF THIS?
Ischemic stroke caused by spontaneous artery dissection
(e.g., carotid or vertebral artery) is an important etiology
of cerebrovascular accident among young patients like
the one in this case. Cervical MRA is the gold standard
for the diagnosis of arterial dissection. Cervical disc
disease is a common etiology in a patient with neck or
shoulder pain (or both) without cause or neurologic
symptoms, when cervical magnetic resonance imaging
is negative; however, spontaneous SAD should be considered in the differential diagnosis when a patient, especially in a case of a younger patient, presents with acute
new-onset neck or shoulder pain without an identified
cause, followed by the onset of neurological symptoms.
In the setting of arterial dissection, blood pressure control
and continuous clinical evaluation are necessary.

N. Nagino et al.

REFERENCES
1. Marik PE, Mclaughlin MT. Spontaneous subclavian artery
dissection: a pain in the neck diagnosis. BMJ Case Rep 2013;2013
http://dx.doi.org/10.1136/bcr-2013–201223.
2. Garewal M, Selhorstt JB. Subclavian artery dissection and triple
infarction of the nervous system. Arch Neurol 2005;62:1917–9.
3. Winblad J, Grolie T, Ali K. Subclavian artery dissection. Radiol Case
Rep 2015;7:626.
4. Schievink WI. Spontaneous dissection of the carotid and vertebral
arteries. N Engl J Med 2001;344:898–906.
5. Putaala J, Metso AJ, Metso TM, et al. Analysis of 1008 consecutive
patients aged 15 to 49 with first-ever ischemic stroke: the Helsinki
Young Stroke Registry. Stroke 2009;40:1195–203.
6. Savitz SI, Caplan LR. Vertebrobasilar disease. N Engl J Med 2005;
352:2618–26.
7. Hu XY. Relationship between vertebral artery hypoplasia and posterior
circulation stroke in Chinese patients. Neuroradiology 2013;55:291–5.
8. Iwamuro Y, Nakahara I. Occlusion of the vertebral artery secondary
to dissection of the subclavian artery—case report. Neurol Med Chir
(Tokyo) 2005;45:97–9.
9. Arning C. Spontaneous dissection of the subclavian artery and its
branches. Vasa 2005;34:50–2.