Download Posterior Stroke and HINTS

Posterior Stroke
and the
H.I.N.T.S exam
LMH Emergency Rounds
Prepared by Shane Barclay
Posterior Stroke Presentation
Often will only present with one symptom:
Vertigo
The differential is ‘peripheral’ causes of
vertigo versus ‘central’ causes.
Definition of Vertigo
Perception of movement (rotational or otherwise)
where no movement exists
Pathophysiology
• Mismatch or asymmetric activity of visual,
vestibular, and/or proprioceptive systems
Must distinguish peripheral from central cause
• Peripheral: 8th CN, vestibular apparatus
• Central: Brainstem, cerebellum
Case
86 year old woman presented with a 2 day history of fairly
sudden onset severe vertigo and nausea. No vomiting. One
to two weeks prior described a mild viral URTI with some
sinus ‘fullness’.
PHx: HTN – controlled
Meds: HCTZ
Exam: CN normal, finger to nose normal, heel/shin normal.
Strength and reflexes normal. CV/chest benign. DixHalpike exam non conclusive. Slight ataxia on walking.
Labs – CBC, glucose, lytes, GFR – normal.
Neurology
July 8, 2014
“Frequency of False-Negative MRIs and non-lacunar infarcts”
Saber Tehrani AS et al.
105 patients over 13 yrs were reviewed. All presented with
acute vestibular syndrome (days to weeks of continuous
vertigo, nausea or vomiting, head-motion intolerance, gait
unsteadiness and nystagmus).
Early MRI (within 48 hrs of symptoms) was 47% sensitive
for detecting acute infarcts of < 10 mm (most involving the
inferior cerebellar peduncle or lateral medulla)
and 92% sensitive for infarcts > 10 mm
Detailed beside exam including HINTS was > 99% sensitive
for diagnosing infarcts of all sizes. (HINTS was false
negative in only one case)
Differentiating Central versus
Peripheral Vertigo
PERIPHERAL
Benign Positional Vertigo
Migranous Vertigo
Vestibular Neuritis
Meniere’s
Viral Labyrinthitis
Drug Toxicity
Differentiating Central versus
Peripheral Vertigo
PERIPHERAL
CENTRAL
Benign Positional Vertigo
Cerebellar infarct
Migranous Vertigo
Vertibrobasilar TIA
Vestibular Neuritis
Chiari Malformation
Meniere’s
Multiple Sclerosis
Viral Labyrinthitis
Neoplasms
Drug Toxicity
Clinical Features
Peripheral Vertigo
Onset
Sudden
Severity
Intense spinning
Pattern
Paroxysmal, intermittent
Aggravated by
position/movement
Yes
Nausea/diaphoresis
Frequent
Nystagmus
Horizontal
Fatigue of
symptoms/signs
Yes
Hearing loss/tinnitus
May occur
Abnormal tympanic
membrane
May occur
CNS symptoms/signs
Absent
Clinical Features
Peripheral Vertigo
Central Vertigo
Onset
Sudden
Sudden or slow
Severity
Intense spinning
Ill defined, less intense
Pattern
Paroxysmal, intermittent
Constant
Aggravated by
position/movement
Yes
Variable
Nausea/diaphoresis
Frequent
Variable
Nystagmus
Horizontal
Vertical or multidirectional
Fatigue of
symptoms/signs
Yes
No
Hearing loss/tinnitus
May occur
Does not occur
Abnormal tympanic
membrane
May occur
Does not occur
CNS symptoms/signs
Absent
Usually present
Diagnosis
Sensitivity of Studies
Preference is for MRI due to greater
sensitivity
HINTS Exam
Stroke
September 2009
Journal of the American Heart Association
HINTS to Diagnose Stroke in the Acute Vestibular Syndrome: Three-Step
Bedside Oculomotor Examination More Sensitive Than Early MRI DiffusionWeighted Imaging
Jorge C. Kattah, Arun V. Talkad, David Z. Wang, Yu-Hsiang Hsieh
and David E. Newman-Toker
Diagnosis
Test
HINTS
MRI (24hrs)
MRI (48hrs)
CT non con
Sensitivity
100%
68.40%
81%
26%
HINTS Exam
3 Components
1. Head Impulse test of vestibulo-ocular reflex
function
2. Observation for Nystagmus in primary, right,
and left gaze
3. Alternate cover Test for Skew deviation.
HINTS Exam
HEAD IMPULSE (or Head Thrust)
1. Have patient fix their eyes on your nose
2. Move their head in the horizontal plane to the left and right.
3. When the head is turned towards the normal side the
vestibular ocular reflex remains intact and eyes continue to
fixate on the visual target
4. When the head is turned towards the affected side, the
vestibular ocular reflex fails and the eyes make a corrective
saccade to re-fixate on the visual target. It is reassuring if
the reflex is abnormal (due to dysfunction of the peripheral
nerve) ie abnormal means it is a peripheral cause of vertigo.
HINTS Exam
NYSTAGMUS
Peripheral causes of vertigo (ie BPV) can give
HORIZONTAL nystagmus but ONLY in one direction.
Move the head right, left or up and down and the
nystagmus will ONLY be in one direction.
However if you have the patient look to the left and there is
left beating nystagmus and then have the patient look to the
right and there is right beating nystagmus, that is known as
direction changing nystagmus and that is BAD. ie occurs
with central cause of nystagmus.
Vertical nystagmus is always BAD.
HINTS Exam
TEST of SKEW
Skew is also known as vertical dysconjugate gaze and is a sign
of a central lesion.
1. Have pt look at your nose with their eyes and then
cover one eye
2. Then rapidly uncover the eye and quickly look to
see if the eye moves to re-align.
3. Repeat on each eye
(4. or if pt complains of binocular diplopia that is a
positive test too)
Summary
Patient presents with Continuous Vertigo and no hearing loss.
1 Head Impulse
- Normal patient, eyes will remain fixed on the target
(your nose)
- Peripheral Vertigo Pt – rapid rotation of the head
toward the affected side will result in loss of fixation
and movement of the eyes away from the target.
- With Central Vertigo, there is typically NO corrective
saccade.
i.e. you want there to be saccade motion
Summary
Patient presents with Continuous Vertigo and no hearing loss.
2. Nystagmus
- Normal Pt’s will have NO nystagmus
- Pt’s with peripheral vertigo cause will have
unidirectional, horizontal nystagmus
- Pt’s with central vertigo can have rotatory or vertical
nystagmus, or direction changing nystagmus (right
beating nystagmus when looking right and left beating
nystagmus when looking left)
i.e. you want there to be unidirectional, horizontal
nystagmus.
Summary
Patient presents with Continuous Vertigo and no hearing loss.
3. Test of Skew
- Normal Pt’s will have no skew deviation.
- Pt’s with peripheral vertigo will also not have any
skew deviation
- Pt’s with central vertigo will have misalignment and
therefore as the cover is moved off from the eye,
a slight correction (up or down) will occur.
i.e. you want the patient to NOT have any skew deviation.
Summary
Patient presents with Continuous Vertigo and no hearing loss.
So, you can rule out a central cause of vertigo if:
Pt has no corrective saccade with head impulse
Pt has unidirectional horizontal nystagmus.
Pt has no skew deviation.
If the patient has any of the following along with suggestive history, they
should be admitted for further evaluation (MRI) for possible central stroke:
Pt has no corrective saccade with head impulse.
Pt has rotatory or vertical nystagmus or direction changing
nystagmus
Pt has misalignment and correction of eyes with uncovering of the
eye.
HINTS – Summary
Head Impulse
You want the Head Impulse test to be ABNORMAL to reassure
you the patient has a peripheral cause of vertigo.
Nystagmus
You want the nystagmus to be fast beating in ONLY ONE
DIRECTION to reassure you the patient has a peripheral cause of
vertigo.
Test of Skew
You want PERFECT VERTICAL ALIGNMENT of the eyes to
reassure you the patient has a peripheral cause of vertigo
Head Thrust Test
Pt with peripheral cause of vertigo – there is corrective saccade
Nystagmus – Central
Nystagmus is in both directions
Test of Skew
Positive test for Central lesion
HINTS Exam
If ANY one of the HINTS exam components is
positive, the patient needs a neurological
consult/MRI.
A positive HINTS exam: 100% sensitive and 96%
specific for the presence of a central lesion.