Case Report:
A 19-year-old woman came to the emergency department around noon because
of acute vertigo with unsteadiness and light-headedness triggered by
changing her head position. She woke up around 3:00 am with vertigo on
the day of the emergency department visit. Her symptoms partially
subsided when lying in bed and not moving. She denied headaches,
photophobia, migraines, vomiting, diarrhea, recent viral illness, head
injury, loss of hearing, or trauma. She previously had a similar episode
of vertigo that resolved on its own. She had no other relevant medical
history.
With the present episode, the emergency department physician performed a
Dix-Hallpike maneuver and diagnosed a left-sided BPPV,presumably of the posterior canal , though the details of
any elicited nystagmus were not reported. The patient was treated with aleft-sided Epley maneuver, and upon a repeat Epley
maneuver, her symptoms and nystagmus were documented as resolved by the
emergency department physician. During the first Epley maneuver, the
patient developed vertigo when lying with her head turned to the left
side. After her head was moved to point to the floor for two minutes
more, her vertigo stopped. No imaging was obtained, and the patient was
discharged directly from the emergency department with a diagnosis of aleft-sided BPPV , presumably pcBPPV.
While the patient was in the emergency department, she was also enrolled
in a clinical trial to assess her vertigo symptoms. A video-oculography
(VOG) study was obtained by our research staff before undergoing any
treatment maneuvers. The VOG study was not repeated after the emergency
department physicians’ treatment, as the patient had been discharged
following the resolution of symptoms. The details of the recording and
analysis are described in the legend of Supplemental Video 1. Hearing
was normal.
Video Head Impulse Testing (vHIT) was performed for the horizontal
canals, and gains were within normal limits without corrective saccades
(head left, 0.83; head right, 0.97). With the VOG, with the patient
sitting upright in the dark at center gaze, there was a right-beating
spontaneous nystagmus of 1-2 °/s. In the supine position, there was a
right-beating spontaneous nystagmus of 3 °/s. The cause of the weak
spontaneous nystagmus on center gaze and in the supine position could
have been from the residual effects of prior testing maneuvers, the
presence of pseudo-spontaneous nystagmus, or be within normal
limits.[8-12] In the chin-down (bow position), there was a
right-beating sustained horizontal nystagmus (maximum slow-phase
velocity [SPV] of 7°/s). In the right Dix-Hallpike maneuver, no
nystagmus occurred. In the left Dix-Hallpike maneuver, there was a
right-beating horizontal nystagmus that was sustained (maximum SPV of 12
°/s). In the SRT, in the right ear-down position, there was a
crescendo-decrescendo right-beating nystagmus, lasting around 40 seconds
(maximum SPV of 12 °/s), as shown in Supplemental Video 1. In the left
ear-down position, there was a briefer decrescendo left-beating
nystagmus, lasting around 15 seconds (maximum SPV of 13°/s), as shown in
Supplemental Video 2. Since the chin-down position elicited
right-beating nystagmus, a diagnosis of right-sided
hcBPPV , with geotropic horizontal positional nystagmus
was thought most likely.[13]
In summary, the diagnosis by the emergency department clinicians wasleft-sided BPPV , presumably of the posterior
canal , for which they applied an “appropriate”left-sided Epley maneuver. However, after the emergency
department visit, the expert review of the research VOG recordings found
the overall picture was most consistent with hcBPPV,
geotropic variant, on the right side . The BPPV was likelyright-sided , based on the intense right-beating nystagmus
induced in the bow position.[13] Thus, in the emergency department,
the patient was diagnosed with the incorrect side, the incorrect canal,
and applied the incorrect treatment. Nevertheless, the patient’s
symptoms and nystagmus resolved. Despite several diagnostic and
treatment errors in this patient with BPPV, we wondered why the
treatment worked, so we performed simulations to test the hypothesis.