“Time will tell.” This is a quote from my mom, Marge Desmond. She likes to say this to point out that the truth usually prevails. A recent study out of China supports my informal research, and years-long soap-boxing about the inadequate diagnostic process for patients suffering from Benign Paroxysmal Positional Vertigo (BPPV). I have pointed out on this blog that the majority of patients with BPPV never undergo positional testing. This recent study discusses the second potential for error associated with misdiagnosis of BPPV. That is, misinterpreting the Dix-Hallpike exam.
Many years ago, as a less experienced practitioner, I would be frustrated when a patient presented with a history suggestive of BPPV, yet the Dix-Hallpike (as well as all other tests) was negative. Here is a short blurb from my practice website discussing an informal study we did many years ago:
BPPV is by far the most common cause of episodic vertigo, and can be successfully treated in one or two office visits approximately 90% of the time. Unfortunately, our in-office data indicates that almost 40% of patients complaining of positional vertigo are not detected through positional testing at the time of the initial exam. In 2001, we asked a series of these patients to return a few days later for repeat positional testing, this time being careful to avoid any provoking movements for several hours prior to the repeat examination. On repeat testing, 40% (10 of 25) had a positive positioning test and a clear diagnosis of BPPV was made.
There is very little literature addressing the issue of BPPV that is inactive at the time of exam. For a more in-depth review see Norre (1994) Diagnostic Problems with Patients with Benign Paroxysmal Positional Vertigo, Laryngoscope. BPPV is such a common and easily treated condition that re-examination, or a trial of home treatment, should be considered when the complaints are suggestive of BPPV, even if the exam is negative.
The recent study looked at more patients than we did (133 versus 25) and added some elements that we did not explore. However, their results are consistent with our findings from 2002. For patients meeting the criteria of: 1. A history suggestive off BPPV and, 2. A negative Dix-Hallpike exam on initial examination, 57% (compared to our 40%) had a positive exam on re-examination within 10 days. They also report that 26% of patients seen for suspected BPPV had a negative initial exam. Not surprisingly, the duration of symptoms was longer in the negative Dix-Hallpike group (presumably due to delayed diagnosis), but their response to treatment was no different from those with a positive initial examination.
The bottom line? A negative Dix-Hallpike does not, and cannot, rule out BPPV, and BPPV must remain as a suspected diagnosis in those complaining of positional vertigo. Our treatment approach to these patients was described on this site last year.
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