Stroke or Vestibular Neuritis? Use the HINTS

The other day, Tom and I had a patient with the symptom of continuous vertigo. This is to be distinguished from someone with episodic triggered vertigo, such as when turning their head to the right, which we associate with benign paroxysmal positional vertigo (BPPV). The differential for continuous vertigo includes vestibular neuritis (a relatively benign diagnosis, the “Bells Palsy of Cranial Nerve 8”) and posterior circulation stroke (a potentially lethal disease if missed).

And as deus ex machina, Johnathan Edlow published an article on just this subject.

He believes the old teaching is failing us. We were taught to first ask “dizziness means different things to different people” to distinguish lightheadedness from ataxia from vertigo. If it was was to differentiate central from peripheral by using a constellation of symptoms: sudden or insidious onset, vomiting or not, severity of vertigo. The problem is, patients cannot make the distinction between vertigo and lightheadedness reliably and those distinguishing symptoms are all very insensitive.

So Edlow presents a different approach: timing and triggers.

  • Acute Vertiginous Syndrome (AVS): vertiginous symptoms that lasts days, is continuous and may be accompanied by nausea, vomiting and change with motion. This is not BPPV.
    • Benign: vestibular neuritis, labyrinthitis
    • Serious: posterior circulation stroke, multiple sclerosis, cerebellum hemorrhage
  • Triggered Episodic Vestibular Syndromes (t-EVS): lasts a short time, exacerbated by a specific trigger, such as moving the head or standing up.
    • Benign: BPPV
    • Serious: hypovolemia (hemorrhage, sepsis), central paroxysmal positional vertigo (CPPV)
  • Spontaneous Episodic Vestibular Syndromes (s-EVS): episodes last minutes to hours without a particular trigger
    • Benign: vestibular migraines, Ménière’s disease
    • Serious: TIA
  • Chronic Vestibular Syndromes (CVS): vertigo that lasts weeks to months
    • Benign: medication side effects, anxiety
    • Serious: posterior fossa mass

Our patient suffered from AVS. The HINTS exam has been shown to be even more sensitive the MRI in distinguishing between vestibular neuritis and a posterior circulation stroke.

The Anatomy

Pictured here is an actual photograph from a meticulous dissection. The thing that matters is that the cochlea (responsible for hearing) and vestibular apparatus (responsible for balance) are supplied by the vestibular and cochlear nerve, which come from the vestibulo-cochlear nerve. Both are supplied by the anterior inferior cerebellar artery, part of the posterior circulation. Occlusion of this artery can lead to balance and hearing changes as well as edematous cerebellar strokes that herniate. Hence it’s important to be able to distinguish the cause of acute vertiginous symptoms.

Inflammation of the vestibular nerve leads to vestibular neuritis. Inflammation of the vestibulo-cochlear nerve leads to labyrinthitis.

The Five Questions You Need to Ask in AVS

There are five questions you need to ask in order to distinguish between this central and peripheral cause.

  1. Is there central nystagmus?
  2. Is there skew deviation?
  3. Is the head impulse test negative in a patient with nystagmus?
  4. Are there any CNS signs on exam?
  5. Any gait or truncal ataxia?

If you answer yes to any of these questions, evaluate for a central cause. If all are no, it’s likely vestibular neuritis. These questions will take us through the HINTS exam, but we don’t perform the exam in the order of the letters H-I-N-T-S, instead it’s N – TS – HI. But that doesn’t spell anything.

1. Is there central nystagmus?

First we should talk about nystagmus, the “n” in HINTS. These are the quick saccade movements that occur in patients with vestibular issues. There is a fast followed by slow movement and the nystagmus is named for the direction of the fast component. No nystagmus is considered normal.

Now have the patient look to the left and right. It may be necessary to hold a piece of paper to the side so the patient isn’t looking at anything in particular (which can extinguish nystagmus).

  • Here you can see that when the patient is looking to the left (top drawing), there is a fast component to the right followed by slow to the left.
  • When the patient looks to the right (bottom drawing), there is a fast component to the right followed by slow to the left.

This is unidirectional nystagmus. Contrast this with bi-directional nystagmus.

  • Here you can see that when the patient looks to the left, there’s a fast to the right followed by slow to the left.
  • When the patient looks to the right, there’s a fast to the left followed by a slow to the right.

The fast and slow components change direction when the patient looks in different directions.

Type of nystagmus What’s it mean?
No nystagmus normal state… though you can sometimes see this with a cerebellar stroke. Great.
Spontaneous horizontal nystagmus not diagnostic
Gaze evoked horizontal nystagmus not diagnostic, though probably BPPV
Direction changing horizontal nystagmus Central cause
Vertical nystagmus Central cause
Torsional nystagmus Central cause

Nystagmus if the first thing to look for.

2. Is there skew deviation?

The next question to ask is if the eyes deviate upward and downward when you cover and uncover it. You are looking for small deviations so look first at one eye, cover and uncover both. Then look at the other eye, cover and uncover both.

Tell the patient to focus on your nose.

  1. Cover one of the patient’s eyes
  2. Uncover it and look for an upward deviation. It may be as small as 1 mm.
  3. Cover the other eye. The patient is still looking ahead.
  4. Uncover that eye and that eye may deviate downward 1 mm.

3. Is there head impulse in a patient with nystagmus?

Tell the patient to relax their head and focus on your nose. Then gently rotate the head left and right about 10-15° then quickly bring them back to center.

Normal is no saccade. This is what you would expect in a patient without nystagmus, so if the patient demonstrates no nystagmus in the first step, you do not progress further and get to this step.

If there is a saccade in a patient with vertigo, this represents a peripheral lesion.

Lack of vertigo in a patient with vertigo represents a central problem. So a “normal finding in a patient without vertigo” is the same as an “abnormal finding in a patient with vertigo.”

4. Are there any CNS signs on exam?

Ask if any of these are present.

  • Abnormal neurologic exam → central cause
  • Abnormal hearing exam → central or peripheral
  • Anioscoria → central cause
  • Ptosis → lateral medullary infarct
  • Hoarseness → lateral medullary infarct
  • Loss of facial pain and temperature sensation → lateral medullary infarct
  • Abnormal finger-to-nose or heel-to-shin → cerebellar problem

5. Any gait or truncal ataxia?

  • Cannot sit up without holding the railings → truncal ataxia → cerebellar or brainstem problem
  • Cannot walk without ataxia → gait ataxia → cerebellar or brainstem problem

So what do you do if you suspect a central cause?

Do not order a CT scan. It gives you false reassurance and you’re more likely to send home a posterior stroke than if you hadn’t gotten the CT in the first place.

An MRI with diffusion weighted imaging (which is normally good for strokes) can miss strokes as well. The HINTS exam is said to be better than MRI in the first 48 hours.

Studies have not been done proving that ER docs can do this exam reliably, but it’s not outside of our skill set.

Documentation

So here’s how I may document my exam for patients with an acute vertiginous syndrome.

1. Is there central vertigo?
	*** No Nystagmus → not vestibular neuritis
	*** Spontaneous horizontal nystagums → non-diagnostic
	*** Gaze Evoked horizontal nystagmus → non-diagnostic
	*** Direction Changing nystagmus → possible central cause
2. Skew deviation 
	*** exists suggesting a central cause
	*** does not exist, potentially not a central cause
3. Head impulse test shows
	*** no saccade in a patient without vertigo
	*** saccade in patient with vertigo, possible peripheral cause
	*** no saccade in a patient with vertigo, possible central problem
4. Neurologic testing shows:
	*** normal neuro exam
	*** normal hearing exam
	*** no aniosocoria
	*** no ptosis
	*** no hoarse voice
	*** no facial numbness or temp insensitivity
	*** finger-to-nose and heel-to-shin are normal
5. *** No gait or truncal ataxia

How to Read A Paper

Using evidence in the practice of medicine requires minding three areas:

  1. the best available evidence,
  2. the clinical scenario and
  3. the patient’s values.

There are four steps to carry out this process.

  1. ASK a clinical question (PICO).  During the care of your patients, you’ll come across something to which you don’t know the answer. This uncertainty is the start of your EBM journey. If the answer is well established can easily be found in a textbook, it’s considered background information. If the answer is being newly discovered and found in the literature, it’s considered foreground information.You’ll need to shape that question into one which can be fit to the literature. This most commonly used format is PICO.
    • P = patient – describe your patient, demographics, co-morbidities, etc so you can find as good a match of patients in the literature
    • I = intervention – what is the intervention about which you have a question? Are wondering about the effectiveness of a new drug, the potential harm of continued exposure to a toxin or the usefulness of a new blood test in diagnosing your patient.
    • C = comparison – you need to compare your intervention against something. Usually, this will be against what a placebo drug (for new treatments), unexposed people (for patients exposed to a toxin) or a gold standard test (for new diagnostic tests).
    • O = outcome – what is the outcome you’re looking at? Will the patient’s disease improve? Will the exposure cause cancer or death? Or will the new blood test have a high sensitivity in picking up the disease?
  2. ACQUIRE the evidence. Next, you need to acquire the evidence. This is easier said than done. If you put the question into a search engine you may get thousands of irrelevant hits. Even specialized search engines such as PubMed or Google Scholar can lead to unrelated articles. Using the proper search terms and tools helps narrow down the results.
  3. APPRAISE the evidence. Once you have the article, you need to read it and appraise it’s validity. Is this paper done well? Can you trust the results? Can you use the results? The famous Users Guide to the Medical Literature (from JAMA in the 1990’s by Guyatt and Leavitt) provides a framework for how to evaluate papers based on the type of question.

    We’ll look at these in each of the small groups.

  4. APPLY the evidence to your patient. If you’ve determined the paper is usable, then you need to apply it to your patient. Part of this should include an audit of how well that evidence worked.

How to read papers


Here’s how Anthony Krocko (from Sketchy EBM) reads research papers. He recommends starting with the Methods section first, then Results section and disregarding the Introduction and Discussion (as these are mostly just opinion).



I don’t exactly agree with that. There is some good information in the Introduction. It frames this paper in the context of all the papers that came before it. Similarly the Discussion section frames the results of this paper in this context and extrapolates future studies. Here’s an alternate method to attacking papers.

  1. Read the ABSTRACT to get a general idea of the direction in which we’re going.
  2. Read and interpret all the TABLES and FIGURES, using the captions if needed.
  3. Now you can go and read the METHODS and RESULTS. Armed with the info you learned in Step 2, this should go much more quickly.
  4. Now come up with your own interpretation results of the study.
  5. Now you can read the INTRODUCTION and DISCUSSION. Does this match with what you came up with in the step above?

You can practice with NEJM’s Coffee and Pancreatic Cancer (1981) or just use this to follow along with the videos.

Good luck and happy appraising.

EKG 201

If you’re ready to jump in to try reading some EKG’s, here are Twelve ECG’s (but only 11 cases) for you to practice your ECG skills upon. There’s also an EKG worksheet at this link.

11 Answers

Here are the answers to the EKG’s. Try them on your own first. If you have difficulty then watch these. The first video goes through a lot of of the details on how to read an EKG. So that one is longer. The rest just go through the finer points of each EKG.

  1. EKG 1
  2. EKG 2
  3. EKG 3
  4. EKG 4
  5. EKG 5
  6. EKG 6
  7. EKG 7
  8. EKG 8
  9. EKG 9
  10. EKG 10
  11. EKG 11

ECG 101

If you need help with the basics, watch the ECG 101 series of videos.