When examining a patient who has had transient neurologic symptoms that have now resolved, you have to decide whether or not those symptoms were due to a transient ischemic attack (TIA).
And if you decide it was a TIA, a normal neurologic exam, even of the highest quality, doesn’t help you rule out transient ischemic attack. In this case see my post Transient Ischemic Attack: Know What It Is and Take Immediate Action. Posted on December 2, 2011. The post is a thorough review of how to workup what you (the physician) have decided was a TIA.
Now to Dr. Weingart:
Here is my summary [so you should still listen to the podcast] of Dr. Weingart’s remarks on the HINTS exam of Podcast 33:
The key point of this podcast and all the resources is that posterior stroke can present subtly with only vertigo and subtle signs that might only be brought out by the HINTS exam.
First thing: Benign positonal vertigo is an intermittent vertigo that stops when the patient stops moving his head. So a constant vertigo (one present when the patient is not moving his head) is not benign positional vertigo.
Vertigo is due to acute peripheral vestibulopathy (acute vestibular neuritis or acute labyrinthine neuritis [acute vestibular neuritis with hearing symptoms) or to a brainstem or cerebellar infarct or hemorrhage.
The HINTS exam is used for the patient with isolated vertigo whom you might be inclined to send home with the diagnosis of acute peripheral vestibulopathy because your routine neurological exam is completely normal and they have no worrisome signs or symptoms (vertigo and headache, vertigo and gait ataxia, vertigo and truncal ataxia, vertigo in a patient on anticoagulation [or I think vertigo in a patient on antiplatelet therapy], or vertigo in an older patient.
If the patient has an abnormal neurologic exam or any of the worrisome signs and symptoms above, then he or she needs a neurologist evaluation or an MRI.
You will only do the HINTS exam if none of the above are abnormal and you think that the patient can go home without either a neurologist evaluation or an MRI.
So here is what the HINTS exam consists of:
Head Impulse Testing looking for the presence or absence of the vestibular ocular reflex [the reflex is present in normal patients]. Loss of the reflex indicates that the patient has an acute peripheral neuropathy. If the reflex is maintained (is normal) in a patient with vertigo, this suggests a central cause of vertigo (brainstem or cerebellar stroke or bleed).
Nystagmus looking for vertical nystagmus (indicates a central cause of vertigo) or bidirectional nystagmus (also indicates a central cause). Unidirectional nystagmus is nystagmus in which the fast component is in only one direction regardless of which side the head is turned to. Unidirectional nystagmus is consistent with a peripheral vestibular neuropathy.
Test for Skew is the final component of the HINTS exam. Here we are looking for a vertical disconjugate gaze. That is, the eyes are misaligned vertically (one eye is higher than the other). Sometimes it can be obvious. But sometimes it can only be demonstrated with the alternate cover test because the patient can overcome the misalignment by fixation. In this test you have the patient look at your nose and then you cover one eye. This prevents the covered eye from fixating. And rapidly remove your hand from in front of the covered eye. Then what you’ll see is that covered eye that is misaligned coming back into alignment and that is abnormal. What you are seeing is the realignment of your eyes as they fixate on your nose. You want to test both eyes. If the patient complains of binocular double vision that is also due to a vertical skew deviation.
On the video below, Dr. Weingart shows how to do the Head Impulse Test using an iphone and the $0.99 SloMo app from the app store (Outstanding–there are also slow motion apps available on Google Play for the Android smart phone):
Below is Dr. Weingart’s video, Video for Diagnosing Posterior Stroke, which goes along with Podcast 33 (but you need to listen to Podcast 33, embedded above, before watching this video):
Be sure to click on and read the show notes link above for Podcast 33. Dr. Weingart has included a number of outstanding resources that should be carefully read and reviewed. Also click on and read the comments above as they often have helpful thoughts.
In EMCrit Podcast 34- ACLS Guidelines embedded below, Dr. Weingart spends the first three minutes going over some questions raised in Podcast 33 and he reinterates the most important concepts of Podcast 33. So you can listen to the first three minutes related to Post 33 right here:
And here is a transcript of the first three minutes of Dr. Weingart’s remarks at the start of Podcast 34:
Resources cited by Dr. Weingart in the show notes above:
HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging [PubMed Abstract] [PubMed Related Citations] [Full Text HTML] [Full Text PDF]. Stroke. 2009 Nov;40(11):3504-10. doi: 10.1161/STROKEAHA.109.551234. Epub 2009 Sep 17. Kattah JC1, Talkad AV, Wang DZ, Hsieh YH, Newman-Toker DE.
Video for Diagnosing Posterior Stroke. This is the video for cerebellar stroke diagnosis. Listen to the podcast [above] first.Video clips are from Dr. David Newman-Toker’s site and from the article: Kattah JC, Talkad AV, Wang DZ, Hsieh YH, Newman-Toker DE. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke. 2009 Nov;40(11):3504-10.
Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome [Full Text PDF]. CMAJ 2011. DOI:10.1503/cmaj.100174
A practical approach to acute vertigo [Full Text PDF]. Pract Neurol 2008; 8: 211–221.
The HINTS Exam in Vertigo–Journal Club Podcast #10: January 2014. The EMJClub Emergency Medicine Podcast, The Washington University Emergency Medicine Journal Club. “Dr. David Newman-Toker, the authority on the HINTS exam, joins me to talk about oculomotor testing in acute vertigo…”
Transient Ischemic Attack: Know What It Is and Take Immediate Action. Posted on December 2, 2011 by Tom Wade MD.