Does Dizziness Cause You Diagnostic Disequilibrium?
Although most providers have developed a standardized approach for the evaluation of dizziness, the variation from one provider to the next is likely as vast as the difference in the ways patients report their symptoms.
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ACEP Now: Vol 34 – No 03 – March 2015For several reasons, including improved outcomes, utilization control, operational efficiency, and patient safety, it’s time to narrow the gap in practice variation.
Most cases of vertigo are benign and are not associated with serious pathology or likely to result in bad outcomes no matter what we do. However, the real key is to trim the diagnostic fat without becoming so diagnostically lean that you miss something important. One way, and perhaps the most common, is the shotgun approach (check all the boxes and let the tests guide you), and another is the dartboard approach (random selection of testing combinations based on gestalt). However, a rational approach to dizziness is available with a review of the evidence.
Nine months ago, I started down my evidence-based pathway, evaluating a 67-year-old female patient with new-onset dizziness. I was working at a facility that had easy access to MRI. Despite the fact that brain CT lacks sensitivity for posterior fossa pathology, it is often ordered in the evaluation of dizziness. We do so because MRI frequently isn’t available emergently for this complaint and brain imaging of some kind just seems to make sense. Well, with MRI readily available, I elected not to order the standard CT, which rarely if ever yielded any positive findings, and ordered an MRI, which ultimately was normal as well. This patient led me to challenge whether imaging is necessary at all in patients with dizziness, whether CT has any utility, and in which patients imaging should be obtained. Three studies answered these questions for me, taking care of my diagnostic disequilibrium.
In 2012, Chase et al from Beth Israel Deaconess Medical Center in Boston published a study to determine what clinical factors were associated with stroke in vertiginous patients.1 MRIs of the brain were obtained during the ED visit or within two weeks. Of the 131 patients, 12 (9.2 percent) experienced a cerebellar or brainstem stroke (posterior fossa). CTs were negative in all five stroke cases in which one was performed. The complaint of gait instability and subtle neurological findings were associated with stroke, with odds ratios (ORs) of 9.3 and 8.7, respectively. Of particular note was that nystagmus was only present in a third of those with stroke and in a fifth of those without stroke.
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4 Responses to “Myths in Emergency Medicine: Diagnostic Imaging for Dizziness”
March 22, 2015
Alan J. Sorkey MDGood to know that CT scan are worthless in these cases. I will be sure to send a copy of this article to the patient I recently saw with dizziness and an acute brainstem infarct on CT scan. He had just been sent home from a stroke center with no CT scan.
How does this balance with the malpractice payout for missed stroke diagnosis? How about factoring in the time spent in responding to patient complaints and to peer review.
Take-home point: CT is not worthless in the evaluation of dizziness. It is what the patient expects, it is what the peer review panel (in retrospect) will expect. A normal CT makes for a happy patient and protects the doctor, very worthwhile in my opinion.
March 22, 2015
Chuck PilcherSince a large percentage of posterior fossa strokes are from vertebral artery dissections, what is the value of CT Angiograms?
March 22, 2015
Jonathan EdlowAlthough it is good to see an emphasis on the diagnosis of the dizzy patient, Dr. Klauer is perpetuating another myth – that “nystagmus is unreliable”. He is right that the mere presence of any kind of nystagmus does not help to differentiate peripheral from central causes of the acute vestibular syndrome. However that is akin to saying that “the presence of EKG changes is unreliable” for diagnosing an ACS. All abnormalities are not created equal; a flat T wave does not have the same significance as ST segment elevation.
It’s the same with nystagmus. Its mere presence does not always help – but the KIND of nystagmus is VERY helpful to the diagnostician in sorting out the cause of dizziness. Some of the source for this comes from the Chase article but this article (I was an author) only described presence or absence of nystagmus (unfortunately, this is the way more EPs chart it), but it’s not meaningful.
In a patient with ongoing dizziness, one should be hesitant to diagnose vestibular neuritis or labyrinthitis if there is NO nystagmus. The nystagmus is “direction-fixed” – i.e., the fast component always beats to the same side no matter what direction the patients is looking in.
On the other hand, direction-changing nystagmus is this setting means that there is a central process (probably stroke). So does torsional or vertical nystagmus. Patients with peripheral causes will have direction-fixed horizontal nystagmus.
In positional (episodic) dizziness, these rules shift. Emergency physicians must learn some of the details about nystagmus as it can really help us to make a confident diagnosis.
The presence/absence of nystagmus but more importantly, its quality, is very helpful in making a specific diagnosis in dizzy patients.
April 23, 2015
strength in numbers: dizziness | DAILYEM[…] Cribbed from this March ACEP Now article: […]