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Clinical Case Report

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Atypical “nine” syndrome in bilateral pontine
infarction
A case report
Shugang Cao, MM, Rongfeng Wang, MM, Mingwu Xia, MB, Wen’an Xu, MM

∗

Abstract
Rationale: “Nine” syndrome, that is “eight-and-a-half” syndrome associated with hemiplegia and hemidysesthesia, is a rare

disorder. This study aimed to report a Chinese patient with acute bilateral pontine infarction manifesting as eight-and-a-half syndrome
plus hemiplegia (atypical nine syndrome), and also the clinical and neuroimaging findings were explained and discussed with review of
the literature.
Patient concerns: A 79-year-old woman experienced sudden vertigo, nausea, vomiting, and weakness at her left arm and leg.
The neurological examination disclosed her right horizontal gaze palsy, internuclear ophtalmoplegia (INO), and right-sided peripheral
facial paralysis combined with slight left-sided hemiplegia, which were consistent with atypical nine syndrome.
Diagnoses: Cranial magnetic resonance imaging (MRI) displayed acute multiple ischemic infarction, involving bilateral pontine
tegmentum, basilar part of right paramedian pontine, and left cerebellar hemisphere. Intracranial MR angiography (MRA) revealed
right middle cerebral artery occlusion, no clear visualization of bilateral vertebral arteries, and basilar artery hypoplasia with stenotic
segments.
Interventions: Thrombolysis could not be performed due to the time window. The patient was given low molecular weight heparin
for anticoagulation because of posterior circulation and progressive stroke.
Outcomes: The vertigo disappeared, and a notable improvement with minimal restriction in the right horizontal gaze and partial
relief of her facial paralysis were found at discharge, while her left hemiparesis was fully resolved. No recurrence of cerebral infarction
was observed during follow-up as well.
Lessons: This case report with atypical nine syndrome is fairly rare. Nine syndrome may refer to the lesion located in unilateral
tegmentum of the caudal pontine plus paramedian pontine, with an important localization value.
Abbreviations: DWI = diffusion-weighted imaging, INO = internuclear ophtalmoplegia, MLF = medial longitudinal fasciculus, MRA
= magnetic resonance angiography, MRC = Medical Research Council, NIHSS = National Institutes of Health Stroke Scale, MRI =
magnetic resonance imaging, PPRF = paramedian pontine reticular formation.
Keywords: diffusion-weighted imaging, eight-and-a-half syndrome, one-and-a-half syndrome, pontine infarction, stroke

combined with ipsilateral fascicular seventh cranial nerve palsy,
which is caused by circumscribed lesions of the pontine
tegmentum involving the abducens nucleus, the adjacent facial
colliculus, and the ipsilateral medial longitudinal fasciculus
(MLF).[1] Rosini et al proposed the concept of “nine” syndrome,
which showed eight-and-a-half syndrome plus hemiplegia and
hemidysesthesia (81/2 + 1/2 = 9).[2] Since then, few variants of nine
syndrome have been reported. Mahale et al presented two
patients with a variant of nine syndrome who manifested as eightand-a-half syndrome plus hemiataxia.[3] Maas and Verrips
reported a typical “nine syndrome” patient in Neurology.[4]
Here, we reported a Chinese patient with acute bilateral pontine
infarction presenting as atypical nine syndrome (eight-and-a-half
syndrome plus hemiplegia), and discussed the clinical and
neuroimaging findings with review of the limited literature.

1. Introduction
The so-called “eight-and-a-half” syndrome, originally proposed
by Eggenberger in 1998, refers to “one-and-a-half” syndrome
Editor: N/A.
Conflicts of interest: The authors declare no conflicts of interest with respect to
the research, authorship, and funding of this article.
Department of Neurology, Hefei Affiliated Hospital of Anhui Medical University,
Hefei, Anhui Province, China.
∗

Correspondence: Wen’an Xu, Department of Neurology, Hefei Affiliated Hospital
of Anhui Medical University, 246 Heping road, Hefei, Anhui Province 230011,
China (e-mail: xuwenan550305@126.com).

Copyright © 2019 the Author(s). Published by Wolters Kluwer Health, Inc.
This is an open access article distributed under the terms of the Creative
Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NCND), where it is permissible to download and share the work provided it is
properly cited. The work cannot be changed in any way or used commercially
without permission from the journal.

2. Case presentation
A 79-year-old Chinese woman was admitted to our inpatient
department due to sudden vertigo, nausea, vomiting, and
weakness at her left arm and leg approximately 6 h after onset.
In terms of medical history, she had a history of obesity and

Medicine (2019) 98:28(e16378)
Received: 19 January 2019 / Received in final form: 6 May 2019 / Accepted: 13
June 2019
http://dx.doi.org/10.1097/MD.0000000000016378

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Cao et al. Medicine (2019) 98:28

Medicine

Figure 1. (A–D) Cranial MRI. Axial diffusion-weighted imaging (DWI) showed a high-intensity lesion comprising bilateral pontine tegmentum, basilar part of right
paramedian pontine, and left cerebellar hemisphere (A and B, white arrows), with low apparent diffusion coefficient signals in corresponding regions, indicating an
ischemic lesion (C and D, black arrows).

carotid atherosclerosis with plaque in the right common carotid
artery. Electrocardiogram showed sinus rhythm, left anterior
hemiblock, and abnormal ST segment depression. Cranial
magnetic resonance imaging (MRI) displayed acute multiple
ischemic infarction, involving bilateral pontine tegmentum,
basilar part of right paramedian pontine, and left cerebellar
hemisphere (Fig. 1a–d). Intracranial MR angiography (MRA)
revealed the right middle cerebral artery occlusion, no clear
visualization of bilateral vertebral arteries, and basilar artery
hypoplasia (the maximum diameter of basilar artery is 1.89 mm)
with stenotic segments.
After admission, thrombolysis could not be performed due to
the time window. The symptoms of right facial paralysis and left
hemiplegia were slightly aggravated (Her NIHSS score was 5),
and the patient was given low molecular weight heparin for
anticoagulation. Routine use of atorvastatin statin and symptomatic supportive treatment were given simultaneously. About 7
days later, the vertigo disappeared, and a notable improvement in
her symptoms was found at discharge. The final neurological
examination revealed minimal restriction in the right horizontal
gaze and partial relief of her facial paralysis, while her left
hemiparesis was fully resolved without dystaxia. During followup, the patient had no recurrence of cerebral infarction.

hypertension. She was diagnosed as bilateral cerebellar infarction
1 month before her admission, and she was given regular
secondary prevention. The findings of physical examination were
listed as follows: temperature (T): 36.7°C, pulse rate (P): 75 times/
min, respiration (R): 18 times/min, and blood pressure (BP): 150/
100 mm Hg; there were no abnormal findings in the lungs, heart,
and abdomen. On neurological examination, she was alert, and
her cognitive function was also normal. She presented with right
horizontal gaze palsy, internuclear ophthalmoplegia (INO), and
right-sided peripheral facial paralysis combined with slight leftsided hemiplegia (Medical Research Council (MRC) scale, V ).
She achieved stable and accurate results in finger-nose test, while
failed to complete the inspection of other coordinate movements.
The Babinski sign was negative bilaterally. There was no
paresthesia as well. Her score of National Institutes of Health
Stroke Scale (NIHSS) was 3.
The results of laboratory test were as follows: coagulation test
showed that D-dimer level was 1.000 mg/mL (normal range, 0–
0.500 mg/mL), and biochemical test demonstrated that triglyceride level was 7.20 mmol/L (normal range, 0.45–1.81 mmol/L). In
addition to those abnormal findings, the remaining test results
were normal. Echocardiography showed left ventricular diastolic
dysfunction. Carotid color ultrasonography disclosed bilateral
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3. Discussion

sclerosis, tumors located in the pontine, etc. Although our patient
had two onsets of ischemic stroke, the prognosis was satisfactory,
which might be related to basilar artery hypoplasia and possible
presence of compensatory collateral circulation.[9]
In conclusion, we reported a Chinese patient with eight-and-ahalf syndrome associated with hemiplegia, appearing with
atypical nine syndrome as a consequence of pontine infarction.
Such case report was fairly rare. Nine syndrome may refer to the
lesion located in unilateral tegmentum of the caudal pontine plus
paramedian pontine, with an important localization value for
diagnosis.

In 1967, Fisher, for the first time, proposed the concept of oneand-a-half syndrome (conjugated horizontal gaze palsy and
INO), in which the lesion involved the ipsilateral abducens
nucleus or paramedian pontine reticular formation (PPRF), and
the ipsilateral MLF.[5] Subsequently, Eggenberger put forward
eight-and-a-half syndrome (i.e., one-and-a-half syndrome plus
ipsilateral peripheral seventh cranial nerve palsy) in 1998.[1]
Accordingly, some new variants of eight-and-a-half syndrome
have been successively proposed, such as “fifteen-and-a-half”
syndrome (i.e., one-and-a-half syndrome plus bilateral seventh
cranial nerve palsy proposed by Bae et al [6]), nine syndrome (i.e.,
eight-and-a-half syndrome plus hemiplegia and hemidysesthesia
presented by Rosini et al[2]), and “thirteen-and-a-half” syndrome
(i.e., eight-and-a-half syndrome plus ipsilateral fifth cranial nerve
palsy introduced by Allbon et al[7]). Although Rosini et al. first
proposed the concept of nine syndrome,[2] Uysal et al had
previously reported a patient with the right pontine infarction
who manifested as eight-and-a-half syndrome combined with
transient hemiparesis, which should belong to atypical nine
syndrome.[8] In the present case, the patient exhibited one-and-ahalf syndrome, peripheral right facial palsy, and mild left-sided
hemiparesis, which were consistent with the characteristics of
eight-and-a-half syndrome along with contralateral hemiparesis
(i.e., atypical nine syndrome). Although the clinical manifestations on admission were very similar to the case reported by
Uysal et al,[8] the neuroimaging findings were distinctly different.
The clinical manifestations of this patient could be explained
by the anatomical location of the infarcts on DWI. The large
lesion in the right paramedian pontine tegmentum might not only
involve the ipsilateral abducens nucleus or horizontal gaze center
in PPRF and MLF, but also involve the adjacent facial colliculus,
configuring eight-and-a-half syndrome. The right lacunar paramedian pontine infarction, involving the corticospinal tract,
might result in mild left-sided hemiplegia. However, the
difference was the absence of contralateral sensory disturbance,
which might be due to the lesion not extending the medial
lemniscus. In brief, we presumed that the infarcts in the right
pontine were responsible for the patient’s atypical nine syndrome.
The definite involvement of the corticospinal tract was consistent
with the left-sided hemiplegia, which suggested a direct tissue
damage caused by ischemia rather than a transient extension of
the peri-infarct edema as recently postulated by Uysal et al.[8] In
addition, although the patient had lesion in the left pontine
tegmentum and right cerebellum, the corresponding focal
neurological signs could not be detected in the examination.
Nine syndrome is rare in clinical practice. The etiology
spectrum of several reported cases referred to vascular infarction
or hemorrhage,[2–4,8] which was different from that of eight-anda-half syndrome. Our case was the first nine syndrome reported
in China. The etiology was also considered to be vascular
infarction. However, it should be differentiated from multiple

4. Patient consent
The patient provided consent for the writing and publication of
this case report.
Written informed consent was obtained from the patient for
the publication of this case report and any accompanying images.

Author contributions
Conceptualization: Shugang Cao, Rongfeng Wang, Mingwu Xia.
Funding acquisition: Mingwu Xia.
Investigation: Shugang Cao, Rongfeng Wang.
Methodology: Shugang Cao, Rongfeng Wang, Wen’an Xu.
Supervision: Mingwu Xia, Wen’an Xu.
Validation: Mingwu Xia.
Visualization: Shugang Cao.
Writing – original draft: Shugang Cao.
Writing – review & editing: Shugang Cao, Rongfeng Wang,
Mingwu Xia, Wen’an Xu.

References
[1] Eggenberger E. Eight-and-a-half syndrome: one-and-a-half syndrome
plus cranial nerve VII palsy. J Neuroophthalmol 1998;18:114–6.
[2] Rosini F, Pretegiani E, Guideri F, et al. Eight and a half syndrome with
hemiparesis and hemihypesthesia: the nine syndrome? J Stroke
Cerebrovasc Dis 2013;22:637–8.
[3] Mahale RR, Mehta A, John AA, et al. Nine syndrome: A new neuroophthalmologic syndrome: Report of two cases. Ann Indian Acad Neurol
2015;18:335–7.
[4] Verrips A. Maas RPPWMTeaching Video NeuroImages: Nine syndrome
in inferior paramedian pontine infarction: More than meets the eye.
Neurology 2017;89:e95–6.
[5] Fisher CM. Some neuro-ophthalmological observations. J Neurol
Neurosurg Psychiatry 1967;30:383–92.
[6] Bae JS, Song HK. One-and-a-half syndrome with facial diplegia: the 15 1/
2 syndrome? J Neuroophthalmol 2005;25:52–3.
[7] Allbon DS, La HB. Thirteen-and-a-half syndrome. J Neuroophthalmol
2016;36:191–3.
[8] Uysal S, Demirtastatlidede A, Selcuk OY, et al. Diffusion-weighted
imaging in eight-and-a-Half syndrome presenting with transient hemiparesis. Clin Neuroradiol 2013;23:235–6.
[9] Park JH, Roh JK, Kwon HM. Ischemic stroke patterns and hemodynamic
features in patients with small vertebrobasilar artery. J Neurol Sci
2009;287:227–35.

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