54歳男性; めまい
• 高血圧, 高脂血症の既往がある54歳男性.
• 前日までは特に問題無し.
朝起床時に体のフラツキを自覚。立ってられなくなり救急要請.
車内で嘔気多数. 1回嘔吐あり. 食物残渣.
• 体がふらつくという訴え.
一方方向へ傾くことは無い. 同様のエピソード無し.
感冒症状無し.
• 構音障害, 嚥下障害, 複視, 耳鳴り, 麻痺は無し.

DIZZINESSの原因
South Med J. 2000 Feb;93(2):160-7
• 12 trialのMeta-analysis (primary care 2, ER 4, Referral center 6)
• 12 trials, N=4536での解析. 原因 頻度
Peripheral vestibular BPPV 16%[4-44]
• 末梢性前庭神経症状 44%, 迷路炎 9%[3-23]
メニエール病 5%[0-10]
中枢性前庭神経症状 11%,
その他(薬剤など) 14%[0-30]
精神疾患 16%,
Central vestibular 脳血管疾患 6%[0-20]
その他 39% 脳腫瘍 <1%[0-6]
その他(MS, 片頭痛) 3%[0-12]
Psychiatric 精神疾患 11%[2-26]
過換気症候群 5%[0-24]
非前庭N, 非精神 Presyncope 6%[0-16]
平衡障害 5%[0-15]
その他 13%[0-53]
不明 不明 13%[0-37]

South Med J. 2000 Feb;93(2):160-7
プライマリケア
救急
めまいクリニック
診療状況別の原因頻度 神経内科
50.000%
37.500%
25.000%
12.500%
0%
末梢性前庭神経症状 中枢性前庭神経症状 精神疾患 非前庭神経 非精神疾患 不明
末梢性 中枢性 非前庭神経
診療状況 精神疾患 不明
前庭神経症状 前庭神経症状 非精神疾患
プライマリケア 43% 9% 21% 34% 4%
South Med J. 2000 Feb;93(2):160-7
救急(ER) 34% 6% 9% 37% 19%
めまいクリニック 46% 7% 20% 20% 18%
神経内科 49% 19% 10% 17% 10%

めまいの訴えは変化する
• めまいを訴える872名の患者で初期問診と,
再度病歴聴取時の症状の一致性を評価.
Mayo Clin Proc. 2007;82(11):1329-1340
• 62%は1つのTypeに分類できないめまい,
• 52%は回答が変化. 2回目の評価
V(15) F(50) U(58) D(52) L(95) C(34)
Vertigo(V)(20) 30% 15% 10% 20% 20% 5%
1回目の評価
Faint(F)(39) 10.3% 53.8% 12.8% 5.1% 10.3% 7.73%
Unsteady(U)(58) 3.4% 10.3% 56.9% 6.9% 15.5% 6.9%
Dizzy(D)(69) 2.9% 8.7% 10.1% 33.3% 36.2% 8.7%
Light-headed(L)(85) 1.2% 12.9% 9.4% 17.6% 54.1% 4.7%
Confused(C)(33) 0% 9.1% 9.1% 12.1% 21.2% 48.5%
めまいの患者では, めまいの性状に捕われすぎる必要は無い.
むしろ, めまいの起きた状況の方が重要となる

• Vital Sign BP130/60, HR 100reg, BT 36.8, Sat 98%, RR 22
• 臥位の状態で左向き眼振あり. 水平性か回旋性かは判別困難.
開眼にて悪心訴え, それ以上の診察はできなかった.
• 顔貌左右差無し, 提舌正中, 構音障害無し. 顔面知覚左右差無し.
睫毛反射正常. 明らかな四肢麻痺無し. 感覚障害無し.
四肢失調も認められない.
• プリンペラン, アタPを投与し, やや症状軽快
• その後, 眼振は全眼位で右向き眼振. 眼球運動障害無し.
対光反射迅速.

病歴, 所見より末梢 VS 中枢を評価
前庭神経炎を示唆 Strokeを示唆
徐々に発症するめまい 急性発症のめまい
めまいの前駆症状複数回認める
頸部痛, 頭痛を伴わない 頸部痛, 頭痛を伴う
複視など神経症状を認める
年齢<50yr 年齢>50yr
他の脳血管障害リスクを認める
外傷の既往あり
神経所見異常無し HITが正常
CMAJ 2011;183:E571-E592

中枢性を疑うSIGNS
• 中枢性の眼振
– Downbeat nystagmus; 小脳中心, 尾側, 桃の傷害を示唆
原因 頻度 原因 頻度
塞 25% 腫瘍 3%
小脳変性 24% アルコール性小脳失調 2%
多発性硬化症 13% 動静脈奇形 2%
発達障害/奇形 12% AIDS, 家族性周期性失調 各1%
薬剤性 4% Viral encephalitis, 放射線 各1%
外傷 3% 原因無し 5%
– その他, 方向交代制眼振, Purely vertical nystagmus
持続性, 非減衰性眼振
起立不可, 異常肢位
局所症状(+)
Horners syndrome
Dysarthria, Dysphagia, Diplopia, Dysmetria
感覚障害, 難治性しゃっくりは, 中枢障害を示唆
(Otolaryngologic Clinics of N Am 2000;33:issue3)

末梢 VS 中枢の鑑別
• Acute vestibular Syndrome(AVS)
(回転性めまい, 眼振, 嘔気, Head-motion intolerance, 歩行障害)
– AVSでER受診し, 1つ以上のStroke Riskを持つ患者101名を対象
(Stroke 2009;40:3504-10)(Prospective)(Stroke 76名, 末梢性25名)
– Reference standardをMRI, CTで診断された脳 塞とし,
中枢性めまいに対する身体所見の有用性を評価.
• 身体所見は3つ; 水平HIT, 方向交代性眼振, Skew deviation(斜変位)
• HIT; 中枢性ではHITのVestibulo-ocular reflexは正常
• 方向交代性眼振; 末梢性ならば眼振は一方向性.
垂直方向性の眼振も同様だが, 頻度が少ない.
• Skew deviation; 左右のVestibular toneのバランスが障害され,
垂直方向の眼球変位が起こる.
眼球位置を合わせようと, 頭位を傾けることもあり

末梢 VS 中枢の鑑別
• Skew deviationは17%に認められたが, 複視を自覚したのは3名のみ
• Skew deviationの約60%は延髄, 橋側面の病変による
PAVS(25) CAVS(76) NLR central Sn Sp NLR Stroke
頭痛, 頚部痛 12% 38% 0.70[0.56-0.88] General neurological signs 19% 100% 0.81[0.72-0.91]
重度の体幹失調 0% 34% 0.66[0.56-0.77] Obvious oculomotor signs 28% 100% 0.72[0.63-0.84]
垂直, 回旋性眼振 0% 12% 0.88[0.81-0.96] Severe truncal ataxia 33% 100% 0.67[0.56-0.79]
眼球運動障害 0% 21% 0.79[0.70-0.89] Any obvious signs 64% 100% 0.36[0.27-0.50]
3-Step Exam 4% 100% 0.00[0.00-0.11] Initial MRI with DWI 88% 100% 0.12[0.06-0.22]
方向交代性眼振 0% 20% 0.80[0.72-0.90] Dangerous bedside HINTS 100% 96% 0.00[0.00-0.12]
Skew deviation(+) 4% 25% 0.78[0.67-0.91]
h-HIT 正常 0% 93% 0.07[0.03-0.15]
• Skew deviation, h-HIT, Direction-changing nystagmusを
3-step bedside examination batteryとして行うと(HINTS)
Sn 100%, Sp 96%, LR(+) 25[3.66-170.59], LR(-) 0.00[0.00-0.11]で
中枢性の病変を示唆する.
– 通常の診察での感度は51%,
発症早期のMRIの感度も72%(後日のフォローでStrokeと判明)であり,
それら検査よりも優れているという結果.

HEAD IMPULSE TEST • 前庭機能を評価するTest
• VORを評価
(Vestibulo-ocular reflex)
患者姿勢; 座位
向かい合い, 検者の鼻を見るよう指示
両手で患者の頭部を保持し,
Midlineより20度程度,
素早く頭部を回旋させる.
A; 正常: 患者の目線は
検者の鼻から動かない
前庭機能良好, VOR(+)
Strokeを示唆
B; 異常: 患者の目線が一旦
検者の鼻から外れる
前庭機能異常, VOR(-)

James D. Fix, et al. 神経解剖学集中講義 第1版 90-91, 2007
前庭眼反射 oculo-vestibular reflexの経路

小脳小節, 小脳片葉の障害では
反射は正常となる.
前庭眼反射に異常がでる部位
James D. Fix, et al. 神経解剖学集中講義 第1版 90-91, 2007

前庭神経核の限局性 塞ならば
PICA 塞でもHIT陽性の脳幹 塞となるか？
• 理論上はなるが, 報告例はかなり乏しい.
• 2010年のStrokeに1例報告あり, Stroke 2010, 41:1558-1560
• 53yr女性, HTとDMあり. めまいとふらつきを主訴に受診.
1560 Stroke July 2010
左向きの回旋性眼振を認め, HIT陽性であった.
脳幹症状, 麻痺, 感覚障害のいずれも認めず.

HEAD IMPULSE TEST; 末梢 VS 中枢の鑑別
• 回転性めまいを主訴にER受診した33名
+ 既にStrokeの診断がついている10名でHITを施行
(Reference Standard; MRI, 術者Blind, Strokeは35/43)(Neurology 2008;70：2378-85)
– HIT(-)/Stroke(+) 31/34,
HIT(+)/Stroke(-) 8/8
– Neg HITのStrokeに対するSn 100%, Sp 72%
HIT(+)ならば中枢性のVertigoはほぼ否定可能
• HIT, 方向交代制眼振, Skew deviationの感度, 特異度
CMAJ 2011;183:E571-E592
感度 特異度 LR(+) LR(-)
HIT正常 85%[79-91] 95%[90-100] 18.39[6.08-55.64] 0.16[0.11-0.23]
PICA, SCA 塞 99%[96-100] - - 0.01[0.00-0.10]
AICA 塞 62%[35-88] - - 0.40[0.20-0.80]
方向交代制眼振 38%[32-44] 92%[86-98] 4.51[2.18-9.34] 0.68[0.60-0.76]
Skew deviation 30%[22-39] 98%[95-100] 19.66[2.76-140.15] 0.71[0.63-0.80]
• AICA 塞に関しては, HIT異常でも中枢除外が困難...

つまりHITとは
• PICA 塞に伴う前庭神経症状と
末梢性前庭神経障害との鑑別には非常に有用
• 例外は前庭神経核の単独 塞だが, 非常に稀.
• AICA 塞は内耳 塞によりHITが末梢性パターンを示す
• ただしその場合は難聴を伴う.
脳 塞で難聴を伴うのは99%AICA 塞.
0.7%がPICA 塞.
• つまり, 難聴+前庭神経症状ではHITはアテにならないが,
前庭神経症状単独ならばHITは非常に有用と言える.

• ちなみに,
• 右向き眼振の際には, 右回旋位 → 正中位 でHITが末梢パターン,
左向き眼振の際には, 左回旋位 → 正中位 でHITが末梢パターンとなる.
• 前庭神経炎では眼振は健側方向となる.
右回旋運動では右三半規管,
左回旋運動では左三半規管が刺激されるため,
HITは患側方向への回旋時に末梢パターンを示すようになる.

Isolated Nodular Infarction
Stroke 2009;40:487-491
mPICA 塞で小脳小節のみ病変を認める場合は,
HIT正常の急性の前庭神経症状を呈する.
その場合眼振は患側,
体幹は健側に倒れることが多い.
Head-shaking Nystagmusも
患側方向へ認める.
前庭神経炎ではその逆！
眼振は健側,
体幹は患側に倒れる.
17

PICA 塞の眼振
Stroke 1993;24:76-83
36名のPICA 塞の症状を評価 症状 PICA
(小脳 塞部位は不明) 頭痛(頸部, 後頭部) 64%
Vertigo 78%
PICA 塞だが,
嘔吐 61%
小脳小節, 桃の 塞かどうかは不明 歩行不安定 75%
四肢失調 50%
歩行失調 58%
脳幹症状 33%
眼振 75%
患側方向 47%
健側方向 5%
両側性 11%
垂直方向 11%
18

reported similar results: of 29 patients with vertebrobasilar peduncle, and anterior inferior cerebellum including the floc-
insufficiency, 21% had episodic vertigo for at least 4 weeks culus.9 Since AICA always supplies the lateral pontine teg-
as the only presenting symptom.5 I recently reported three pa- mentum and middle cerebellar peduncle, AICA territory in-
tients with anterior inferior cerebellar artery (AICA) infarction farcts usually involve the brainstem and are virtually never
who experienced isolated episode of recurrent vertigo, fluctu- limited to the cerebellum itself whereas infarcts in the territory
AICA 塞による急性前庭神経障害
ating hearing loss, and/or tinnitus (similar to MeniereMs dis- of the PICA or SCA usually involve only the cerebellum.
ease) as initial symptoms 1-10 days prior to the infarction. 6 There are common anatomic variants, in which AICA domi-
All of these data suggested that isolated episodic vertigo with nance on one side and PICA dominance on the opposite side
or without auditory symptom can be the only manifestation are commonly seen in normal person. At times either the AI-
of transient ischemia within the vertebrobasilar circulation. CA or PICA is absent or hypoplastic, in which case one AI-
Isolated vertigo especially can occur when there is a stenosis CA-PICA supplies the usual territory of both arteries. The in-
AICAは前庭神経 末梢, 中枢双方へ栄養している血管. of the caudal or middle portion of the basilar artery (presuma-
bly close to the AICA origin) or widespread slow vertebroba-
ternal auditory artery (IAA) is a usual branch of AICA and
supplies the eight cranial nerve, the cochlea and vestibular
silar flow on MRA.4,6 However, it is still unclear whether iso- labyrinth. In terms of collateral circulation, in addition to the
脳底動脈下半分より起始し, 内耳, 橋側面, 中脳脚, 小脳の前下部を栄養.
lated episodic vertigo originate from the brain or the inner ear.
When isolated vertigo occurs in transient ischemia of the pe-
dorsolateral pons and middle cerebellar peduncle, which are
known to be sensitive to ischemia, inner ear is also particular-
ripheral vestibular labyrinth,1 the superior part of the vestib- ly vulnerable to ischemia since it is supplied entirely by the
AICA 塞は殆どが脳幹を含み, 小脳に限局することは先ず無い.
ular labyrinth may selectively be vulnerable to ischemia, pos- IAA that is an end artery with minimal collaterals from the
sibly due to the small caliber of the anterior vestibular artery otic capsule and has complete absence of collateral circula-
PICA, SCA領域の 塞では小脳に限局することがある.
(AVA) and little collateralization.7 Patients with AVA infarc- tion.1,10,11 By contrast, the retrocochlear eight nerve has an
tion may subsequently develop typical episodes of benign par- abundant collateral blood supply arising from the lateral med-
oxysmal positional vertigo; these have been ascribed to is- ullary artery, the arteries supplying the adjacent dura matter
内耳動脈はAICAから分岐する動脈であり, chemic necrosis of the utricular macule and release of otoco- and the petrous bone, and the inferior lateral pontine artery.12-14
nia into the posterior canal. Since the posterior canal is suppli- A typical pattern of AICA territory infarction on brain MRI
前庭神経, 核, 内耳への血流支配はAICAが強く関連.ed by the posterior vestibular artery, a branch of the common is shown in Fig. 1.
cochlear artery, it may be spared in AVA infarction.7,8 Although
迷路 塞はAICA 塞の重要な所見の1つ. isolated episodic vertigo can occur as a manifestation of ver-
tebrobasilar insufficiency, long-lasting (>6 months) recurrent
episodes of vertigo without other symptoms are almost never
AICA 塞11/12(92%)で迷路 塞を合併.
caused by vertebrobasilar disease.
Three Cerebellar Ischemic
内耳動脈 塞は殆どがAICA, 脳底動脈の
Stroke Syndromes
動脈硬化による生じる.are three major cerebellar arteries: the posterior inferior
There
cerebellar artery (PICA), the AICA, and the superior cerebel-
lar artery (SCA). After supplying branches to the brainstem,
each of these arteries supplies the part of the cerebellum in-
dicated by its name.
Acute vestibular Clin Neurol 2009;5:65-73
J syndrome due to anterior inferi-
or cerebellar artery territory cerebellar infarction

20

AICA 塞では脳幹を絡むことが多いため,
純粋な迷路 塞のみで生じることは稀.
突如発症の回転性めまい, 難聴で生じるが,
難聴はしばしばめまいにマスクされ気づかれないことも多い.
(もしくは神経内科はあまり難聴のチェックはしない)
迷路 塞はMRIでも描出困難な 塞.
脳 塞リスクがあり, 前庭神経症状を来している例では要注意.
MRIが正常だからといって否定できない.
J Clin Neurol 2009;5:65-73

AICA 塞の聴前庭神経症状
82名の解析
回転性めまいが主症状 80/82(98%)
Central ocular motor or vestibular signs* 79/82(96%)
前庭迷路 塞 53/82(65%)
蝸牛 塞 52/82(65%)
前庭, 蝸牛 塞 49/82(60%)
前庭 塞, 聴覚障害無し 26/82(32%)
前庭 塞のみで蝸牛障害無し 4/82(5%)
蝸牛 塞のみで前庭障害無し 3/82(3%)
回転性めまいを認めない 2/82(2%)
聴前庭障害のみで中枢性の症状を認めない 1/82(1%)
*片側性の追視障害, 視線運動性の眼振. 注視による方向交代制眼振,
視覚による前庭反応調節の障害.
J Clin Neurol 2009;5:65-73

AICA 塞は以下の6パターンで発症する.
Group 1 2 3 4 5 6 7
N=82 35 13 3 4 24 1 2
回転性めまいで発症 + + + + + + -
聴前庭障害合併 + + - - - + -
聴覚障害のみ - - + - - - -
前庭障害のみ - - - + - - -
聴前庭機能正常 - - - - + - +
眼球運動障害合併 + + + + + - -
他の神経障害を合併 + + + + + - +
前駆症状として聴前庭症状あり - + - - - - -
Group 6はAICA 塞による前庭神経のみの障害.
内耳動脈を絡む場合, 中小脳脚を含む場合に認められ,
AICA syndromeと呼ぶ.
J Clin Neurol 2009;5:65-73

bone-conducted signals in an acoustic booth. The pure-tone average latencies and interpeak latencies. middle cerebellar peduncle
also showed that the
was obtained by averaging hearing thresholds at 500, 1000, and 2000 We defined hearing loss of cochlear origin as Six days later,
and dorsolateral pons were spared. follows13–17: (1)
Hz. A pure-tone average Ͼ25 dB was regarded as indicative of axial T2-weighted (C) and diffusion-weighted (D)
speech recognition scores corresponded well with the increasing
hearing loss. Mild, moderate, severe, and profound hearing loss was MRI of the brain demonstrated hyperintense foci
hearing thresholds on PTA; (2) despite the hearing loss on PTA, the
defined as 26 to 40, 41 to 70, 71 to 90, and Ͼ90 dB, respectively. We in the left middle cerebellar peduncle, left dorso-
ABR showed no abnormalities or delay in absolute latencies of all
performed additional tests to discriminate between neural and lateral pons, and ventral pons.
waves, but interpeak latencies of wave I-III-V were within normal
AICA 塞と難聴
cochlear causes of hearing loss. Speech discrimination testing was limits; and (3) stapedial reflex testing showed normal reflex thresh-
done with AB Wordlists according to the Korean Hearing Services olds. Vestibular function tests were performed by a computer-based
standard protocol. The stapedial reflex thresholds of each ear at electronystagmography (ENG) system (Nicolet ENG system) and
frequencies of 500, 1000, 2000, and 4000 Hz were measured. included examination of oculomotor movements (saccade, smooth
Measurements of stapedial reflex were performed with a GSI 33 Stroke. 2002;33:2807-2812
pursuit, and optokinetic nystagmus), spontaneous and gaze-evoked
Middle Ear Analyzer, which allows determination of stapedial reflex nystagmus, and caloric responses. All neurotologic evaluations were
12例のAICA 塞 + 突然発症の難聴症例のReview
thresholds up to the 110-dB hearing level. The activating stimuli
Illustrative Cases steps ipsilateral to the examined ear. Reflex
were presented in 5-dB
ness. Ten days before, she had 3 episodes of transient
performed during the acute period.
Case 1: Patient 10 Withthe lowest activatorUnilateral
threshold was defined as Cochlear-Type level that resulted in an left-sided tinnitus and hearing loss lasting a few minutes. One
observable meter deflection.
Hearing Loss
Results
day before, she had 2 episodes of transient isolated vertigo
最も多い責任病変は中小脳脚(11/12). lasted no more than several minutes. On neurologic
A 60-year-old woman with type 2was performed on 12 patients
Auditory brainstem response (ABR) diabetes mellitus and all that
Clinical Features
(Medelec ER94a) with previously described techniques. Rarefac-
回転性めまい, 眼振は全例で合併. examination, she wereafemale; 5 patients were male. Clinical
hypertension developed the sudden onset of vertigo, nausea,
tion click stimuli were used. For ABR, the auditory stimulation was
Seven patients had spontaneous right-beating horizontal
vomiting,ofand hearing loss insoundleft side. presented monaurally
a click 0.1-ms-long, 90-dB the that was On examination, nystagmus with aof admission are summarized component and
data at the time counterclockwise torsional in Tables 1 in
she had aof 10 Hz,4/12で2d-2moの間に前駆症状としてのめまい, 難聴の報告あり.
at a rate spontaneous right-beating horizontal nystagmus
and broadband masking (40 dB less intense than primary and rightward gaze, which changed to a left-beating
2. All patients were alert and orientated on admission.
with a counterclockwise torsional component in primary horizontal nystagmus with a clockwise torsional component
position and Classic featuresthe AICA Infarction* and showed a 12
TABLE 2. with gaze to of right or left. PTA Findings in Patients
on leftward gaze. There were diminished left facial sensation,
moderate sensorineural hearing loss of 50 dB on the left side. left limb dysmetria, and gait ataxia. MRI of the brain
Patient
Stapedial reflexes were recorded at normal levels from both demonstrated hyperintense lesions on axial T2-weighted im-
sides. Speech discrimination scores were 85%Involved left side. 1
Signs and Symptoms Structures Possibly on the 2 3 4 5 6 7 8 9 10 11
ages situated in the left middle cerebellar peduncle and left 12
Normal waveform responses were vestibular bilaterally on ABRϩ
Vertigo, nystagmus Labyrinth,
evoked nerve, vestibular ϩlateral pons (Figure 2). PTA showed a ϩ
ϩ ϩ ϩ ϩ ϩ ϩ mild (40 dB)ϩ
ϩ senso-
ϩ
testing. ENG showed no response to caloric stimulation of the
nuclei, flocculus rineural hearing loss on the left side even though she did not
left side. Axial T2- and diffusion-weighted MRI of nucleibrainϩ
Tinnitus, hearing loss Cochlea, auditory nerve, cochlear
the ϩcomplain of decreased hearing in the ϩ side during the
ϩ ϩ ϩ ϩ ϩ ϩ left ϩ Ϫ ϩ
showed a small infarct in the left ventrolateral pons, but the attack of vertigo.ϩSpeech discrimination ϩ scoresϩwere 30% on
Gait and limb ataxia MCP, anterior inferior cerebellum ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ ϩ
middle cerebellar peduncle and dorsolateral pons were appar- the left side and ϩ on the Ϫ
90% Ϫ right ϩ
side. No stapedial reflexes
ently spared. Brain MRA Spinal trigeminal tract, nucleus
Facial hemianesthesia showed moderate stenosis ofϩ ϩ Ϫ Ϫ ϩ ϩ Ϫ
were elicited from the left side. On ABR testing, no responses
Ϫ
the middle third of the basilar artery. fascicle
Facial paralysis Facial nerve Low-dose aspirinϩ Ϫ Ϫ Ϫ ϩ Ϫ Ϫ Ϫ ϩ Ϫ
were evoked by stimulation on the left side, whereas there
Ϫ Ϫ
(100 mg)sensory signs started. The hearing loss persisted, butϪ
Crossed therapy was Spinothalamic tract Ϫ
were Ϫnormal waveforms on Ϫ right side (Figure 3). ENG
Ϫ ϩ Ϫ
the Ϫ ϩ Ϫ Ϫ Ϫ
the vertigo improved steadily over a few days. Six days afterϪ
Horner’s syndrome Sympathetic fibers Ϫshowed noϪresponse to caloric stimulation ofϪ left side.
Ϫ ϩ Ϫ Ϫ Ϫ ϩ the Ϫ Ϫ
the initial onset of hearing losspeduncle. side and vertigo, the
MCP indicates middle cerebellar in the left
patient complained1 of an exacerbation of AICA infarction. com-
*Based on Adam’s clinicopathological study of the vertigo,

disappearance. All patients with acute auditory syndrome
also had transient vertigo lasting a few minutes, consistent inferior pontine infarction who presented w
with a transient ischaemic attack in the vertebrobasilar deafness, facial palsy, Horner’s syndrome, and
circulation.9 Furthermore, the tinnitus preceding the infarc- 2002, Toyoda et al reported two patients with
tion was identical to that experienced at the time of occlusion who had bilateral hearing loss as a wa
infarction, and isolated vertigo preceding the infarction was an impending stroke.19 No large consecutive clin
identical in quality to the vertigo experienced at the time of AICA infarction has focused on an acute audito
AICA 塞の前駆症状, 前兆として, infarction. as a warning sign of impending infarction.
Most previous reports of an isolated neuro-otological It is well recognised that the tinnitus is a v
symptom as a manifestation of vertebrobasilar insufficiency complaint, not only in association with deafnes
have focused on the acute vestibular symptom of vertigo.10–17 individuals with normal hearing, and it is not u
一過性の耳鳴, 難聴を認める例も報告されている. There have been few reports of an acute auditory syndrome
as an initial manifestation of vertebrobasilar insufficiency. In
as a warning sign of an impending stroke. How
the episodes of tinnitus, the patient No 2 also c
1981, Stephan et al described a patient with sudden bilateral episodic vertigo lasting a few minutes, which
hearing loss caused by basilar artery occlusion who later duration of ischaemia within the posterior
中小脳脚の 塞で多い. developed multiple brain stem dysfunctions with quadriple-
gia and mental change.6 In 1993, Huang et al described seven
Furthermore, the quality of tinnitus was ide
tinnitus experienced at the time of infarction.
patients with sudden bilateral hearing loss caused by It was surprising that all the patients had
同部位では前庭神経症状が主に生じる vertebrobasilar occlusive disease.7 Six had an acute auditory paresis to caloric stimulation yet an incomplete
1646
Figure 3 Magnetic resonance imaging findings in patient 5 with episodic prodromal unilateral hearing loss and tinnitus. (A) T2 weigh
of the brain shows a hyperintense lesion situated in the right middle cerebellar peduncle and right dorsolateral pons. (B) Magnetic r
angiography shows proximal basilar artery stenosis close to the origin of the anterior inferior cerebellar artery.
J Neurol Neurosurg Psychiatry 2003;74:1644–1648
25

眼振あり
あり
BPPVと診断.
BPPVに典型的？
あり 治療の反応性をチェック
なし
めまいと同時に難聴 HITは当てにしない
あり
なし
Skew deviation
脳幹症状, 神経症状 あり
脳 塞, 中枢性病変 !
方向交代制眼振, 垂直眼振
CT, MRIへ
なし
HITは？ 中枢パターン
末梢パターン
前庭神経炎
末梢性めまい HITの使い方

73歳男性; 起立時のふらつき
• 2週間前にDMを診断(HbA1c11.2%), 他にHTがある男性.
• 3日前より立位時の浮動感を自覚.
足に力が入らない感じがあり, 転倒することもあった.
改善しない為に救急要請し, 当院へ搬送となった.
• 臥位時には全く症状無し.
嘔気嘔吐なし. 先行感染症なし, 外傷歴なし. 頸部痛, 頭痛なし.
• 既往歴; 糖尿病, 高血圧(2週間前に診断)
• 内服; ジャヌビア, アムロジン(2日前より事故中断)
• 飲酒なし, 喫煙 10本/d x50年

• 意識清明, BP165/98, HR84reg, RR12, Sat100%, BT36.4
• 起立直後 BP144/60, HR109,
起立3分後 BP140/95, HR104.
• 眼瞼結膜蒼白なし, 口腔内は乾燥. 腋窩乾燥.
胸部∼腹部問題無し.
• 瞳孔3/3, 対光反射問題無し. 眼振なし. 眼球運動問題無し.
顔貌左右差なし, 顔面知覚左右差なし. 舌偏倚なし. カーテン兆候陰性
上下肢バレー陰性, DTR左右差なし.
MMTは上下肢ともに5/5. トーヌス問題無し.
指鼻試験スムーズ, 踵膝試験スムーズ.
• 血糖221mg/dL
• 心エコーは明らかな問題無し. Labでは軽度脱水所見のみ.

• 脱水と判断し, 補液1500ml施行後
• 臥位 BP159/90 HR71, 立位3分 BP123/90 HR100
起立時の浮動感残存. 立位保持が困難で倒れるため入院管理.
• 翌日, 立位後2分経過くらいしてから左向き眼振あり
• 全眼位で左向き眼振(+), 難聴なし.
眼振と同時期に左足の違和感, 脱力を訴える.
座位, 臥位になると眼振消失. 症状も消失する.
• Skew deviationなし. HITは中枢パターン.
脳神経所見は問題無し.
下肢筋力もMMT5/5で問題無し. 感覚左右差なし.
• 臥位時 BP132/79 HR75 立位直後 BP105/73 HR91 立位3分後 BP140/89 HR92
• Mann’s試験で左に傾く. 指鼻試験は昨日と変化無し.

• MRI所見

• 小脳 塞あり, Penumbraへの血流が立位時に低下することで
下肢失調と眼振が生じている.
• 左PICAの本幹部の狭窄.
左小脳小節, 桃の虚血 → 患側への眼振.(左)
左小脳片葉の虚血 → 左上下肢の失調.(特に下肢)
• 姿勢に応じて眼振が誘発されるが, BPPVとも異なり,
脳 塞が原因の病態を Malignant PPV “MPPV”と呼ぶ.