Posterior Stroke and the H.I.N.T.S exam LMH Emergency Rounds Prepared by Shane Barclay
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Posterior Strokeand the
H.I.N.T.S exam
LMH Emergency Rounds
Prepared by Shane Barclay
Often will only present with one symptom:
Vertigo
The differential is ‘peripheral’ causes of vertigo versus ‘central’ causes.
Posterior Stroke Presentation
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
Definition of Vertigo
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. Dix-Halpike exam non conclusive. Slight ataxia on walking.
Labs – CBC, glucose, lytes, GFR – normal.
Case
“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)
Neurology July 8, 2014
PERIPHERALBenign Positional Vertigo
Migranous Vertigo
Vestibular Neuritis
Meniere’s
Viral Labyrinthitis
Drug Toxicity
Differentiating Central versus Peripheral Vertigo
PERIPHERAL CENTRALBenign Positional Vertigo Cerebellar infarct
Migranous Vertigo Vertibrobasilar TIA
Vestibular Neuritis Chiari Malformation
Meniere’s Multiple Sclerosis
Viral Labyrinthitis Neoplasms
Drug Toxicity
Differentiating Central versus Peripheral Vertigo
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
Clinical Features
Sensitivity of Studies
Preference is for MRI due to greater sensitivity
Diagnosis
HINTS Exam
Stroke September 2009
Journal of the American Heart Association
HINTS to Diagnose Stroke in the Acute Vestibular Syndrome: Three-StepBedside Oculomotor Examination More Sensitive Than Early MRI Diffusion-Weighted Imaging
Jorge C. Kattah, Arun V. Talkad, David Z. Wang, Yu-Hsiang Hsieh and David E. Newman-Toker
Diagnosis
HINTS 100% MRI (24hrs) 68.40% MRI (48hrs) 81% CT non con 26%
Test Sensitivity
3 Components
HINTS Exam
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.
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)
HINTS Exam
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.
Summary Patient presents with Continuous Vertigo and no hearing loss.
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
HINTS – Summary
Head Thrust TestPt with peripheral cause of vertigo – there is
corrective saccade
Nystagmus – CentralNystagmus is in both directions
Test of Skew
Positive test for Central lesion
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.
HINTS Exam
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