EBQ:HINTS Exam

Complete Journal Club Article
Kattah, J. et al. "HINTS to Diagnose Stroke in the Acute Vestibular Syndrome: Three-Step Bedside Oculomotor Examination More Sensitive Than Early MRI Diffusion-Weighted Imaging". Stroke. 2009. 40(11):3504–3510.
PubMed Full text PDF

Clinical Question

Is the HINTS exam (Head-Impulse—Nystagmus—Test-of-Skew) more sensitive for diagnosing stroke than early MRI diffusion-weighted imaging in Acute Vestibular Syndrome?

Conclusion

A negative HINTS examination can rule out a stroke better than a negative MRI with DWI in the first 24 to 48 hours after symptom onset with a specificity of 96%.

Major Points

The 3 components of the HINTS exam include:

HINTS Test Reassuring Finding
Head Impulse Test Abnormal
Nystagmus None (normal) or horizontal unilateral only
Test of Skew Normal

Head Impulse Test

Test of vestibulo-ocular reflex function

  1. Have patient fix their eyes on your nose
  2. Move their head in the horizontal plane to the left and right
    • When the head is turned towards the normal side, the vestibular ocular reflex remains intact and eyes continue to fixate on the visual target
    • 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 [1][2]
    • Normally, a functional vestibular system will identify any movement of the head position and rapidly correct eye movement accordingly so that the center of the vision remains on a target.
      • This reflex fails in peripheral causes of vertigo effective the vestibulocochlear nerve
    • It is reassuring if the reflex is abnormal (due to dysfunction of the peripheral nerve)

Nystagmus

  1. Observation for nystagmus in primary, right, and left gaze
    • No nystagmus (normal) or only horizontal unilateral nystagmus is reassuring
    • Any other type of nystagmus is abnormal, including bidirectional nystagmus

Test of Skew

  1. Have patient 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 with on each eye
    • Skew deviation is a fairly specific predictor of brainstem involvement in patients with acute vestibular syndrome. The presence of skew may help identify stroke when a positive head impulse test falsely suggests a peripheral lesion.
    • Skew is also known vertical dysconjugate gaze and is a sign of a central lesion

Inclusion Criteria

At least one stroke risk factor:

Exclusion Criteria

A history of recurrent vertigo with or without auditory symptoms

Interventions

Patients presenting with symptoms of acute vestibular syndrome underwent neurological and vestibular examination according to a standard protocol:

  • head impulse test
  • prism cross-cover test for ocular alignment
  • observation of nystagmus in different gaze positions

All patients underwent neuroimaging, generally after bedside evaluation, otherwise the examiner was masked to these results at the time of clinical assessment.

All patients were admitted for observation and underwent serial daily examinations for evolution of clinical findings.

Outcome

Primary Outcomes

  • A positive HINTS exam: 100% sensitive and 96% specific for the presence of a central lesion.
  • The HINTS exam was more sensitive than general neurological signs: 100% versus 51%.
  • The sensitivity of early MRI with DWI for lateral medullary or pontine stroke was lower than that of the HINTS examination (72% versus 100%, P=0.004) with comparable specificity (100% versus 96%, P=1.0).

Secondary Outcomes

Subgroup analysis

Further Discussion

This was performed in an outpatient setting by neuro ophthalmologists not emergency physicians and may not be generalizable to an ED population

Further Reading

  • Newman-Toker et al. HINTS Outperforms ABCD2 to Screen for Stroke in Acute Continuous Vertigo and Dizziness. Academic Emergency Medicine. Volume 20, Issue 10, pages 986–996, October 2013
  • Babak et al. Application of the ABCD2 Score to Identify Cerebrovascular Causes of Dizziness in the Emergency Department. Stroke. 2012; 43: 1484-1489
  • Perry et al. Prospective validation of the ABCD2 score for patients in the emergency department with transient ischemic attack. CMAJ July 12, 2011 vol. 183 no. 10.

Funding

The National Institutes of Health and the Agency for Healthcare Research and Quality

External Links

See Also

Sources

  1. Barraclough K, Bronstein A. Vertigo. BMJ. 2009;339:b3493
  2. Kuo CH, Pang L, Chang R. Vertigo - part 1 - assessment in general practice. Aust Fam Physician. 2008;37(5):341-7