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Differential Diagnosis and Management of Brainstem and Cerebellar Infarctions
Combined Sections Meeting, February 7, 2015
Indianapolis, IN
Janet O. Helminski, PT, PhD
Professor, Midwestern University
Janet Callahan, PT, DPT, MS, NCS
Clinical Assistant Professor, MGH Institute of Health Professions
Clinical Specialist, Massachusetts General Hospital
(I)
Objectives: Upon completion of this educational session, the participant will be able to:
(A) Apply the process of differential diagnosis in the examination and management of
brainstem and cerebellar infarctions versus acute vestibular pathology.
(B) Identify the constellation of functional impairments associated with specific brainstem,
cerebellar and vestibular syndromes.
(C) Utilize the oculomotor examination to identify lesion locations associated with brainstem,
cerebellar and vestibular structures.
(D) Determine the long-term outcomes of the brainstem and cerebellar lesions.
(II)
Incidence of vertigo and dizziness to Emergency Department. Using data from the
National Hospital Ambulatory Medical Care Survey (NHAMCS), vertigo and dizziness
accounts for 2.6 million visits annually to US emergency departments.5 Of all cases of
dizziness, 32.9% were due to oto-vestibular causes.5 Of all oto-vestibular cases, 5.6%
were due to acute vestibular syndrome.5
(III)
Acute vestibular syndrome (AVS) may be peripheral or central in origin.
(A) Symptoms include rapid onset of:
(1) Severe, continuous vertigo or dizziness
(2) Nausea with retching or vomiting
(3) Gait instability
(4) Head motion intolerance
(5) Nystagmus
(B) Duration of symptoms – days to weeks.
(C) Cause: Most cases of acute vestibular syndrome are of benign cause (vestibular
neuritis or nonbacterial labyrithitis), but approximately 25% are caused by brain stem or
cerebellar strokes.6 Half of stroke patients have no focal neurological signs.6,7
(D) Imaging not sensitive acutely.
(1) CT scans identify 16% of posterior fossa infarctions acutely.8,9
(2) MRI with diffusion-weighted imaging of the brain identifies only 80% of posterior
fossa infarctions in the first day.6
(E) Clinical Examination important in identifying patients with acute central
vestibulopathologies.
(IV)
History:
(A) Medical History – Cardiac Risk Factors. Of patients who sustained a
brainstem/cerebellar stroke, 30% 1 cardiac risk factor and the others had at least 2 risk
factors.10
(1) Arterial hypertension
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
1
(2) Diabetes mellitus
(3) Hyperlipidemia
(4) Cigarette smoking
(5) Atrial fibrillation
(6) Hypercoagulable state
(7) Eclampsia
(8) Recent cervical trauma
(9) Prior myocardial infarction
(10) Prior stroke
(B) History of current symptoms of dizziness/vertigo – rapid onset.
(V)
Brainstem anatomy – The rule of 4 of the brainstem.11 Determine if medial or lateral
brainstem based on medial or lateral structures involved. Determine level of lesion
based on cranial nerves involved (figure 1).
Figure 1. Medial and lateral structures of
the brainstem.
http://www.cixip.com/index.php/page/content/id/1163
Figure 2. Principle arteries of the
brainstem.
(http://neuroanatomylec.blogspot.com/2009/12/brainstem.html)
(A) The 4 medial structures and the associated deficit:
(1) The Motor pathway (corticospinal tract): contralateral weakness of the arm and
leg.
(2) The Medial Lemniscus: contra lateral loss of vibration and proprioception in the arm
and leg.
(3) The Medial longitudinal fasciculus: ipsilateral internuclear opthalmoplegia (failure of
adduction of the ipsilateral eye towards the nose and nystagmus in the opposite eye
as it looks laterally).
(4) The Motor nucleus and neve: ipsilateral loss of the cranial nerve that is affected (III,
IV, VI, XII)
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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Figure 3. Blood supply to the brainstem. Paramedian and long
circumferential branches.1
(B) The 4 lateral structures and the associated deficit:
(1) The Spinocerebellar pathways: ipsilateral ataxia of the arm and leg.
(2) The Spinothalamic pathway: contra lateral alteration of pain and temperature
affecting the arm, leg and rarely the trunk.
(3) The Sensory nucleus of the V: ipsilateral alteration of pain and temperature on the
face in the distribution of the Vth cranial nerve (this nucleus is a long vertical structure
that extends in the lateral aspect of the pons down into the medulla).
(4) The Sympathetic pathway: ipsilateral Horner’s syndrome, partial ptosis and a small
pupil (miosis).
(C) There are 4 cranial nerves in the medulla, 4 in the pons, and 4 above the pons (2 in the
midbrain).
(D) There are 4 motor nuclei in the medial brainstem (cranial nerve III, IV, VI, and XII) and 4
nuclei in the lateral brainstem (V, VII, IX, and XI)
(VI)
Brainstem vascular syndromes.11
(A) The blood supply to the brainstem – vertebral basilar system (Figure 2).
(1) Paramedian branches (Figure 3) – occlusion of the paramedian branches results in
medial (or paramedian) brainstem syndromes (CST involved - motor)
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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(2) Long circumferential branches (Figure 3 and 4)– occlusion of the long circumferential
branches results in lateral brainstem syndromes (spinothalamic tract – sensation)
and cerebellar syndromes (ataxia).
(a) Posterior inferior cerebellar artery
(b) Anterior inferior cerebellar artery
(c) Superior cerebellar artery
Figure 4. Circulation to brainstem
and cerebellum - long
circumferential branches
(http://www.slideshare.net/drpsdeb/cerebellum2013).
Figure 5. Three planes of motion – pitch
(frontal plane), roll (sagittal plane), and yaw
(transverse plane).
(VII) Other Etiologies causing Brainstem Lesions mimicking vestibular lesions
(A) Multiple Sclerosis
(B) Paraneoplastic Syndromes
(VIII) Vestibular Anatomy.
(A) Three Planes of Motion (Figure 5)
(1) Pitch (sagittal plane)
(2) Roll (frontal plane)
(3) Yaw (transverse plane)
(B) Vestibular Ocular Reflex Pathway (Figure 6)
(1) Peripheral vestibular system
(a) Sensory transducer – hair cells located within sensory epithelium.
(1) Crista ampullaris of ampulla of semicircular canal. Hair cells consist of 1
kinocillium and multiple stereocillia. Hairs cells located within cupula –
gelatinous diaphragm.
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
4
Figure 6. Schematic illustrating differences in the semicircular canal-ocular and short-latency
utriculo-ocular connectivity. Blue lines afferent projections, red lines 2nd order connections,
and green lines for abducens neuron projections.4
Schematic illustrating differences in the short-latency utriculo-ocular and semicircular canal-ocular
(2) Maculae of utricle and
sacculus. Weighted sensory
epithelium consisting of hair
cells embedded within the
otolithic membrane with
calcium carbonate crystals
(otoconia) embedded on top.
(1) detect linear
acceleration.
(2) Generate translational
VOR
(b) CN VIII – vestibular nerve (Figure
7). Innervates hair cells and
project to vestibular nuclear
complex.
(1) Two branches of the vestibular
nerve.
(a) Superior vestibular nerve –
fibers originate from lateral
Figure 7 Origin (macula and crista ampullaris)
and termination (vestibular nuclear complex)
of vestibular nerve projections.2
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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canal, anterior canal, and utricle.
(b) Inferior vestibular nerve – fibers originate from posterior canal and
saccule.
(2) Discharge firing rate of vestibular nerve.
(a) At rest, tonic discharge 90 spikes/s, equal on both sides, signally the
brain that the head is not moving.
(b) With movement, asymmetry in discharge firing rate. The canal towards
which the head is turning increases and the opposite side is inhibited.
Firing rate 0-450 spikes/s depending on side.
(2) Central vestibular system
(a) Vestibular nuclear complex (figure 7) - axon projects through medial longitudinal
fasciculus.
(1) Superior vestibular nucleus – projects to oculomotor and trochlear nuclei and
integrates vertical VOR.
(2) Medial vestibular nucleus – projects to abducens nuclei, oculomotor nuclei
and bilaterally to cervical/thoracic spinal cord to integrate horizontal VOR and
vestibular colic reflex.
(3) Lateral vestibular nucleus – projects ipsilaterally to spinal cord to integrate
lateral vestibular spinal tract (protective extension).
(4) .Descending vestibular nucleus – integrates both sides.
(b) Vestibular commissural system
(c) Cerebellum
(1) Flocculus – adjusts and maintains gain of VOR
(2) Paraflocculus – adjusts gain of smooth pursuit
(3) Nodulus – adjusts duration of VOR. Processes otolithic input.
(C) Extrinsic Muscles of Eye and
innervation(Figure 8).
(1) Superior oblique – CN IV
(2) Superior rectus – CN III
(3) Inferior oblique- CN III
(4) Inferior rectus- CN III
(5) Medial rectus – CN III
(6) Lateral rectus – CN VI
(D) Direct Vestibulo-Ocular Projections:
(1) Anterior Canal
(a) Excitation: ipsilateral superior
rectus and contralateral inferior
oblique
(b) Inhibition: ipsilateral inferior rectus
and contralateral superior oblique
(2) Posterior Canal
(c) Excitation: ipsilateral superior
Figure 8. Extrinsic muscles of the eye.
oblique and contralateral inferior
(http://musom.marshall.edu/graphicdesign/ibooks/websiterectus
portfolio-images/)
(d) Inhibition: ipsilateral inferior
oblique and contralateral superior
rectus
(3) Lateral Canal
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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(e) Excitation: ipsilateral medial rectus and contralateral Lateral rectus
(f) Inhibition: ipsilateral lateral rectus and contralateral medial rectus
(IX)
Lesions to the vestibular system – Mechanisms of Compensation.
(A) Inter-relationship of vestibular neurons.
(B) Signs and symptoms of unilateral vestibular deficit.
(1) Static – At rest, asymmetry tonic firing rate results in:.
(a) Spontaneous nystagmus- lesion AVOR pathway – fast phase away from side of
lesion. Peripheral lesion spontaneous ny observed with fixation first 5 days and
without fixation from 5 days – 8 years. Central lesion spontaneous ny observed
with/without fixation.
(b) Decreased tone of extensor muscles side of lesion – lesion graviceptive pathway.
(2) Dynamic – reduced gain of the central vestibular system. Gain = output/input.
(a) Oscillopsia – an illusion that everything in the environment is moving – lesion
VOR pathway.
(b) Postural responses inadequate on side of lesion due to lesion graviceptive
pathway.
(X)
Plane specific classification of central vestibular syndromes based on
oculomotor, postural and perceptual signs.
(A) Planes of motion pitch, roll, and yaw.
(B) Lesion to graviceptive pathways results in vestibular tone imbalance (asymmetrical
resting firing rate), with the head is at rest, resulting in a syndrome consisting of a
perceptual tilt, head and body tilt, vertical misalignment of the visual axes (skew
deviation) and ocular torsion.
(C) Localizing nystagmus in brainstem disorders.12,13
Table 1. Localizing nystagmus in brainstem disorders.12,13
Plane
Direction of
Location of Lesion
Nystagmus
(Fast Phase)
Roll
Contraversive
Pontomedullary
(Frontal)
ocular torsion
Contraversive
Interstitial nucleus of Cajal
ocular torsion
Ipsiversive ocular Pontomesencephallic
torsion
Ipsiversive ocular Rostral interstitiaul nucleus
torsion
of the medial longitudinal
fasciculus
Pitch
(Sagittal)
Upbeat only
Downbeat only
Paramedian
pontomesencephalis (ventral
tegmental tract, brachium
conjunctivum)
Medulla (perihypoglossal
nuclei)
Flocculus
Duration
Side of
Lesion
Transient
Unilateral
Permanent
Unilateral
Transient
Unilateral
Permanent
Unilateral
Bilateral
Bilateral
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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Yaw
(horizontal)
Upbeat or
downbeat or
transitions
Contraversive
Horizontal
Paramedian pontomedullary
Bilateral
Root entry zone of the
vestibuar nerve, medial and
superior vestibular nuclei,
and paramedian pontine
reticular formation
pontomedullary syndromes,
vestibular neuritis
Unilateral
Combined
Torsion and
syndromes
horizontal
(roll and
yaw)
(D) Signs of plane specific vestibular syndromes.12
Unilateral
Table 2. Signs of Plane Specific Vestibular Syndromes.12
Plane
Roll
Pitch
Yaw
Vertical
Misalignment
of Visual
Axes (Skew
Deviation)
x
Ocular
Torsion
Head Tilt
Body Tilt
x
x
Forward/
backward
x
Forward/
backward
Falls
Forward/
backward
Rotation/
lateral
Perceptual
Tilt
Past
Pointing
Vertical
Horizontal
Straight
ahead
x
(E) Graviceptive pathway for roll.12 Pathway crosses at level of pons. Subjective visual
vertical is most sensitive sign in roll plane
Table 3. Graviceptive pathway for roll.12
Location of Lesion
Arterial
Ocular Tilt Reaction
Supply
Ipsiversive Contraversive
Peripheral (superior
Vertebral
X
vestibular nerve)
Pontomedullary
Vertebral
X
Junction (medial and
superior vestibular
nuclei)
Pontomesencephalic Paramedian
X
from Basilar
Thalamus
Paramedian
None
None
Thalamic
Vestibular Cortex
ThalamoNone
None
geniculate,
temporal
branches of
CMA, deep
perforators
Subjective Visual Vertical
Ipsiversive Contraversive
x
X
X
X
X
X
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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(F) Frequency subjective visual vertical (SVV) tilt, skew deviation, ocular torsion, and ocular
tilt reaction (OTR) in acute unilateral brainstem and thalamic infarctions.3
Table 3. Frequency subjective visual vertical, skew deviation ocular torsion, and ocular
tilt reaction in acute unilateral brainstem and thalamic infarctions.3
Ocular Torsion (%)
Lesion
Patients SVV Tilt Monocular Binocular
Skew
OTR (%)
(no.)
(%)
(%)
Brainstem
Medullary
36
94
27
55
44
33
(Wallenbeg’s
syndrome)
Pontomedullary
13
100
60
20
23
7.7
Pontine
34
91
47
33
26.5
12
Pontomesencephalitc
12
92
64
18
25
25
Mesencephalic
16
94
54
38
37.5
25
Mesodiencephalic
Anterior polar
4
0
0
0
0
0
thalamic
Posterlateral
17
65
13+
20+
0
0
thalamic
Paramedian thalamic
14
64
29
43
57
57
Total
111
94
47
36
31
20
(G) HINTS to Diagnose Stroke in the Acute Vestibular Syndrome – Three step bedside
examination.10
(1) Examination.
(a) Head Impulse Test
(b) Direction-changing nystagmus in eccentric gaze
(c) Skew deviation (vertical ocular misalignment
(XI)
Clinical Examination:
(A) Neurological screen to identify focal neurological signs.
(1) Motor screen
(2) Sensory screen
(3) Cranial nerves (other than III, IV, and VI)
(4) Oculomotor examination
(a) Fixation/alignment
(b) Extra-ocular movements
(c) Saccades
(d) Pursuit
(e) Gaze holding
(f) VOR
(g) Vergence
(B) Disorders of Fixation (Spontaneous nystagmus)
(1) Downbeating nystagmus:
Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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a. Most common form of acquired spontaneous nystagmus.
b. Associated with lesions in the pontomedullary tegmentum and
flocculus/araflocculus of the cerebellulm.
c. Possibly associated with brainstem connects from Anterior Semicircular
canal.
(2) Upbeating nystagmus.
a. Caudal Medulla
b. Ventral tegmental tract
(3) Torsional nystagmus
(C) Disorders of Alignment: Skew deviation (vertical ocular misalignment).
(1) Symptom:
a. Vertical diplopia
b. Subjective visual vertical
(2) Differential diagnosis
a. Graviceptive pathway
b. CN IV lesion
(3) Tests: Monocular v binocular
a. Bucket Test14
i. Ipsiversive v contraversive tilt
b. Maddox Rods
c. Upright v Supine Position Test15
(D) Disorders of gaze holding
(1) Peripheral Vestibuar Dysfunction
a. Non-direction changing due to vestibular tone imbalance
b. Alexanders Law
(2) Central Vestibular Dysfucntion
a. Direction changing
b. Neural Integrators
i. Horizontal
ii. Vertical
(E) Disorders of the VOR (Head Impulse Test)
(1) Test of peripheral vestibular function
(2) Positive in isolated medial vestibular nucleus lesions
1.
2.
3.
4.
5.
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Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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Differential Diagnosis and Management of Brainstem and Cerebellar Infarcts. February 7, 2015.
This information is property of Janet Helminski, PT, PhD and Janet Callahan, PT, DPT, MS,
NCS and should not be copied or otherwise used without express written permission of the
author.
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