Why You Shouldn’t Ask “What Do You Mean, Dizzy?”
Why You Shouldn’t Ask “What Do You Mean, Dizzy?”
According to Dr Jonathan Edlow, an emergency physician at Beth Israel Deaconess Medical Center in Boston, the evaluation of a dizzy patient is a common occurrence in the ED and in the office, which can be frustrating and challenging for both clinician and patient. Dr Edlow covered this topic during his lecture at the American College of Emergency Medicine 13th annual symposium in Seattle (ACEP13) entitled “Why ‘What Do You Mean Dizzy?’ Should Not Be the First Question You Ask of a Dizzy Patient.”
The traditional approach to the “dizzy” patient starts by trying to place the predominant symptom into one of 4 categories:
This approach assumes that patients can reliably select a single category or lead the clinician to select one of these dizziness subtypes—and that these 4 categories are reliably linked with a somewhat limited differential diagnosis. Unfortunately, recent research and our day-to-day clinical experience bears out that both assumptions are frequently untrue. Patients often describe a combination of these symptoms rather than just one, or they are not really able to distinguish one from another. And even when they do, the correlation with the category they “choose” does not correlate with the final diagnosis.
Dr Edlow described a more fruitful approach to the evaluation of dizziness by focusing more on other aspects of the history—specifically timing, triggers, and associated symptoms, followed by a complaint-directed physical exam with special attention to specific germane aspects of the neurologic exam and (when indicated) selective testing.
The mnemonic he uses is “ATEST”: Associated symptoms, Triggers & Timing, Exam Signs, and Selective Testing.
Associated symptoms may help suggest the cause of dizziness. If there is a change in hearing or ear pain, then a condition causing peripheral vertigo is more likely. If there is headache or neck pain, visual changes, ataxia, or troubles with speech or other CNS complaints, then a central cause of vertigo should be investigated. If the patient takes psychotropic medications or abuses alcohol or drugs, a toxicological cause should be considered. If there is syncope, vomiting, fever, melena, or diarrhea, then a cardiovascular cause or volume or blood loss should top the differential diagnosis.
Timing and triggers also help narrow the list of possible causes. Did symptoms come on gradually or abruptly? Is the dizziness intermittent or continuous? Are there certain activities that either trigger or worsen the symptomatology? Acute onset vertigo that is not intermittent is most likely vestibular neuronitis, but a brainstem or cerebellar stroke might also be the cause.
Dr Edlow noted that although the vast majority of posterior circulation strokes have additional signs and symptoms, about 10% of small cerebellar strokes mimic a peripheral vestibular diagnosis and require careful examination to sort out. Brief episodes of dizziness that last around 1 minute are usually caused by benign paroxysmal positional vertigo (BPPV), but orthostatic hypotension also needs to be considered—especially if the trigger is standing rather than rotational head movements in a horizontal position.
Dr Edlow commented that although research shows that we currently miss only about 1 in 500 posterior circulations strokes, sequelae of these misses, such as a second stroke or brain swelling causing tonsillar herniation can be significant. Unfortunately more imaging is not the answer: CT misses more than 50% of posterior strokes and even MRI can miss 12% of posterior circulation strokes in the first 48 hours.
What is the answer? The same study that showed that MRI had a 12% miss rate found that a properly directed physical exam was 100% sensitive.
The key basic aspects of the physical exam in a patient with dizziness consistent with vertigo include gait, finger-nose-finger, heel-shin, rapid alternating movement, and cranial nerves.
Additional special tests that should be done to evaluate for a possible CNS cause can be remembered with the mnemonic “HINTS”—which stands for Head Impulse, Nystagmus, and Test of Skew.
One should go online and view some of the brief education videos that will better demonstrate these tests, but they will be briefly described here.
A head impulse test checks the vestibulo-ocular reflex. If abnormal, it suggests a peripheral cause. The technique is to grasp the patient’s head, instruct him or her to focus on your nose, and rapidly twist the head 20o to each side. With a normal reflex, the eyes stay on your nose in both directions, making a peripheral cause unlikely. With an abnormal reflex, in one of the directions the eyes move and then correct, suggesting a peripheral cause.
Assessing for nystagmus is explained in the chart below taken from the pocketbook entitled, Quick Essentials Emergency Medicine. The test of skew is to assess for vertical misalignment of the eyes by having the patient again look at the examiner’s nose and alternatively covering one, then the other eye.
An abnormal finding is that one or both eyes will show a vertical correction when uncovered. This suggests a central cause.
Again, go online to find a video to help you with these tests.
According to Dr Edlow, testing for inability to stand and walk, abnormal CNS findings, a normal head impulse test, nystagumus that is not unidirectional horizontal, or an abnormal test of skew all suggest a possible CNS cause of vertigo. If any one of these is present, there should be evaluation for a CNS cause. If none are present the cause is most likely peripheral.
Recommended webpage with links to videos and articles can be found here.