Keywords
cupulolithiasis - supine roll test - apogeotropic - head-shaking maneuver
Introduction
Benign paroxysmal positional vertigo (BPPV) is a common mechanical disorder of the
vestibular labyrinth. Horizontal semicircular canal variant of the BPPV (HSC-BPPV)
is characterized by positional vertigo and direction-changing horizontal nystagmus
inducible by lateral head roll to either side with head anteflexed 30 degrees in the
supine position during the supine roll test (SRT) or head yaw test. [Table 1] shows that 1.94 to 38% of all BPPV patients diagnosed at any specialty clinic suffer
from HSC-BPPV.[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11] Evidently, HSC-BPPV is less common than the posterior semicircular canal BPPV.
Table 1
Frequency of different variants of benign paroxysmal positional vertigo attending
a specialty clinic
|
Authors
|
No. of patients
|
PSC-BPPV
|
HSC-BPPV
|
ASC-BPPV
|
Multiple canals
|
|
Abbreviations: ASC-BPPV, anterior semicircular canal benign paroxysmal positional
vertigo; HSC-BPPV, horizontal semicircular canal benign paroxysmal positional vertigo;
PSC-BPPV, posterior semicircular canal benign paroxysmal positional vertigo.
|
|
De la Meilleure et al,[1] 1996
|
287
|
78.05%
|
16.38%
|
–
|
5.57%
|
|
Honrubia et al,[2] 1999
|
292
|
85.62%
|
5.14%
|
1.37%
|
7.87%
|
|
Macias et al,[3] 2000
|
259
|
93.02%
|
1.94%
|
–
|
5.04%
|
|
Korres et al,[4] 2002
|
122
|
90.16%
|
8.2%
|
1.64%
|
–
|
|
Sakaida et al,[5] 2003
|
50
|
56%
|
38%
|
|
6%
|
|
Imai et al,[6] 2005
|
108
|
64.82%
|
33.33%
|
–
|
1.85%
|
|
Nakayama and Epley,[7] 2005
|
833
|
66.39%
|
10.08%
|
2.28%
|
21.25%
|
|
Cakir et al,[8] 2006
|
169
|
85.21%
|
11.83%
|
1.18%
|
1.78%
|
|
Moon et al,[9] 2006
|
1,692
|
60.9%
|
31.9%
|
2.2%
|
5.0%
|
|
Jackson et al,[10] 2007
|
260
|
66.9%
|
11.9%
|
21.2%
|
–
|
|
Chung et al,[11] 2009
|
589
|
61.8%
|
35.3%
|
2.9%
|
–
|
The HSC-BPPV is caused by the otoconial debris either free-floating within the arms,
commonly long posterior (nonampullary) arm and less commonly short anterior (ampullary)
arm of the HSC (canalolithiasis), or else becoming adherent to the cupula (cupulolithiasis)
on canal (Cup-C) or utricular side (Cup-U).[12]
Because three different possible sites of pathologies within the HSC can masquerade
as apogeotropic HSC-BPPV (short anterior ampullary arm canalolithiasis, Cup-C and
Cup-U types of cupulolithiasis), it is imperative to unerringly localize one of the
three pathological sites responsibly leading to its causation. If the SRT elicits
persistent apogeotropic horizontal nystagmus lasting ≥ 1 minute and there are no changes
in the direction of nystagmus even after repetitive head roll tests, it is explicable
by the horizontal canal cupulolithiasis either on canal-side (Cup-C) or on the utricular-side
(Cup-U).[13] The side to which otoconial debris is adherent (Cup-C or Cup-U) in the horizontal
semicircular cupulolithiasis cannot be determined except perhaps by response to treatment
in selected cases.
The treatment options for the horizontal semicircular cupulolithiasis are not very
well established. The wide variety of methods described in the medical literature
for treating horizontal semicircular cupulolithiasis namely forced prolonged positioning,[14] head-shaking maneuver (HSM),[15]
[16] mastoid vibration,[17] and cupulolith repositioning maneuvers (CuRM) target to detach otoconial debris
adherent to the utricular (Cup-U) and/or canal (Cup-C) side of the cupula.[18]
[19] A recent double-blind randomized controlled trial comparing efficacy of CuRM, HSM,
and modified Lempert maneuver found that the CuRM is theoretically a better therapeutic
option, but the therapeutic efficacy of CuRM was not statistically different compared
with the other two maneuvers on the 2nd day and at 1 week after treatment.[20]
A case of a 25-year-old female patient that presented with an 8-day history of vertigo
on rolling to either of the lateral recumbent positions is reported. Her SRT elicited
an asymmetrical apogeotropic horizontal positional nystagmus (right stronger than
left) lasting ≥ 1 minute on lateral head roll to either side. She was successfully
treated with therapeutic HSM with the head pitched 30 degrees in flexion. At 1 hour
and after 24 hours after the HSM, she neither had vertigo on rolling to either of
the lateral recumbent positions nor the SRT elicited horizontal positional nystagmus.
The author was able to video record the SRT eliciting apogeotropic horizontal positional
nystagmus before treatment and its disappearance at 1 hour and after 24 hours.
Case Description
History
A 25-year-old female patient presented in the first week of November 2019 with 8 days
history of vertigo on rolling to either of the lateral recumbent positions. There
was no history of staggering during the walk, diplopia, difficulty in swallowing,
hiccups, drooping of upper eyelids, dysarthria, or facial or limb weakness. There
was also no history of coronary artery disease, diabetes, hypertension, hypothyroidism,
jaundice, craniocervical trauma, cervical radiculopathies, cervical canal stenosis,
rheumatoid arthritis, Paget’s disease, ankylosing spondylitis, low back dysfunction,
spinal cord injuries, or cerebrovascular disease.
Examination
The general physical examination and vitals of the patient were normal. The screening
examination of the cervical spine did not reveal any limitation of movement. The examination
of the back region did not reveal kyphoscoliosis. The examination of the lumbosacral
spine, including straight-leg raising (SLR) test and reverse SLR test, was normal.
The neurological examination revealed normal cranial nerve examination; strength was
grade 5/5 in all four limbs with normal deep tendon reflexes, and bilateral plantar
reflexes were flexor. The examination of the cerebellar system revealed no spontaneous
or gaze-evoked nystagmus, and there was no appendicular or axial incoordination. The
otoneurological examination revealed normal vertical and horizontal saccadic and smooth
pursuit eye movements. The head impulse test was bilaterally normal. The presence
of spontaneous nystagmus was ruled out by using takeaway Frenzel goggles.[21] The Dix–Hallpike test performed, as per the clinical practice guidelines, of the
American Academy of Otolaryngology, Head, and Neck Surgery Foundation,[22] did not elicit positional nystagmus in the 20 degrees head hanging position to the
either side. The SRT was performed with the patient in long sitting on the examination
table. She was made to lay supine with her head landing on a four-inch-thick pillow,
so it got anteflexed to 30 degrees in this position. SRT elicited an apogeotropic
horizontal positional nystagmus on yawing the head maximally to the right as well
as to the left but was visibly stronger on the right. The latency of the apogeotropic
horizontal positional nystagmus was 4 seconds on either side, and its duration is
190 seconds on the right and 60 seconds on the left side ([Video 1]). The SRT indicated the involvement of the left HSC. The characteristics of the
apogeotropic horizontal positional nystagmus did not change during several cycles
of the diagnostic SRT, and lasted ≥ 1 minute, implying in all probability a pathology
of left horizontal semicircular cupulolithiasis either to the canal (Cup-C) or utricular
side (Cup-U).
Video 1Supine roll test elicits an apogeotropic horizontal positional nystagmus on yawing
the head maximally to the right as well as to the left, which is visibly stronger
on the right. The latency of the apogeotropic horizontal positional nystagmus is 4
seconds on either side, and its duration is 190 seconds on the right and 60 seconds
on the left side. The characteristics of the apogeotropic horizontal positional nystagmus
did not change during several cycles of the diagnostic supine roll test, implying
in all probability a pathology of left horizontal semicircular cupulolithiasis.
Diagnosis
The aforesaid clinical history and examination, is consistent with the diagnosis of
left horizontal semicircular BPPV (apogeotropic variant, possibly, left HSC cupulolithiasis).
Video recording of the initial SRT ([Video 1]), not merely facilitated the identification of apogeotropic positional nystagmus
(and hence localization of the involved semicircular canal) but also precisely lateralized
the involved HSC by comparing its strength, as per the Ewald’s second law. The video
recording of the SRT that elicited asymmetric apogeotropic horizontal positional nystagmus
was observed several times on a bigger screen of the computer to identify the weaker
nystagmus, and hence the involved HSC.
Intervention
HSM ([Fig. 1], [
Video 2
]) was performed with the patient in short-sitting and lower limbs hanging on the
long edge of the examination table. The head was anteflexed 30 degrees in the pitch
plane and briskly shaken by the excursions of 30 degrees side-to-side at an approximate
rate of 3 Hz in the yaw axis for around 25 seconds. Two sequent HSM were done in one
session of treatment.
Video 2Head-shaking maneuver (HSM) is performed with the patient in short-sitting and lower
limbs hanging along the long edge of the examination table. The head is anteflexed
30 degrees in the pitch plane and briskly shaken by the excursions of 30 degrees side-to-side
at an approximate rate of 3 Hz in the yaw axis for around 30 seconds.
Fig. 1 Head-shaking maneuver (HSM): The patient instructed to be in short-sitting with lower
limbs hanging on the long edge of the examination table. The head was anteflexed 30
degrees in the pitch plane and briskly shaken by the excursions of 30 degrees side-to-side
at an approximate rate of 3 Hz in the yaw axis for around 25 seconds (right panel).
Owing to the inertial force generated by rapid acceleration and deceleration during
HSM, the otoconial debris adherent to the utricular side of the cupula of horizontal
semicircular canal (in red) detaches and disperses in the utricular matrix (small
red dots).
Prognosis and Intervention
An SRT done at 1 hour ([Video 3]), and repeated 24 hours after ([Video 4]), the therapeutic HSM did not elicit any positional nystagmus. The patient neither
complained of rotational vertigo or any nonvertiginous dizziness either after 1 hour
or 24 hours after the therapeutic HSM indicating cure. She was telephonically questioned
weekly regarding the recurrence of rotational vertigo for the next 4 weeks, and it
was confirmed that she remained symptom free till then.
Video 3The verifying supine roll test of patient performed an hour after the head-shaking
maneuver (HSM) did not elicit any lying down nystagmus or horizontal positional nystagmus
on maximal yawing of the head to the right and left and the patient did not complain
of vertigo either.
Video 4The verifying supine roll test of patient performed 24 hours after the head-shaking
maneuver (HSM) did not elicit any lying down nystagmus or horizontal positional nystagmus
on maximal yawing of the head to the right and left and the patient did not complain
of vertigo either.
Discussion
The apogeotropic variant of HSC-BPPV is caused by either short anterior (ampullary)
arm canalolithiasis due to free-floating otoconial debris or by the latter getting
adherent to the cupula rendering it heavy and gravity sensitive (cupulolithiasis).
The otoconial debris can adhere to either canal (Cup-C) or utricular side (Cup-U)
of the cupula. The treatment options for the horizontal semicircular cupulolithiasis
are not very established. HSM can result in immediate resolution of positional vertigo
and nystagmus if the otoconial debris is adherent to the utricular side of the cupula
(Cup-U). On the contrary, in the Cup-C variant of the horizontal semicircular cupulolithiasis,
the otoconial debris getting detached by HSM is relocated in the HSC either in its
short anterior (ampullary) arm or the long posterior (nonampullary) arm; thereupon
transformation to either geotropic long posterior (nonampullary) arm horizontal semicircular
canalolithiasis or the apogeotropic short anterior ampullary arm canalolithiasis occurs.
The rapid acceleration and deceleration during HSM generate inertial forces in the
otoconial debris adherent to the cupula that causes its detachment. In the case reported
here, two short-term follow-ups at 1 hour and 24 hours after HSM, with verifying SRT,
were undertaken. In either of the two follow-ups, neither the previously elicited
horizontal positional nystagmus was observed, nor did the patient have vertigo on
rolling to lateral recumbent positions. Given the high rate of spontaneous resolution
in HSC-BPPV reported in some studies,[6]
[23] a favorable therapeutic audit of HSM at two short-term follow-ups indicate a beneficial
effect of applied maneuver rather than spontaneous remission. The dramatic response
of HSM in the reported case indicates that the patient suffered from Cup-U variant
of cupulolithiasis. If the patient had Cup-C variant of HSC-BPPV, the otoconial debris
disengaged by the inertial forces generated during HSM would have fallen into the
canal thereby transforming it to the left horizontal semicircular canalolithiasis
(apogeotropic/geotropic).
Conclusion
Patients with a history of vertigo triggered by positional changes of rolling on the
bed that elicits apogeotropic horizontal positional nystagmus of ≥ 1 minute duration
on SRT, which does not change after many sequences of SRT, in all probability suffer
from the horizontal semicircular cupulolithiasis. An HSM is an excellent option to
offload the heavy cupula by generating inertial forces by rapid acceleration and deceleration
of the head in the yaw axis. If HSM disengages the otoconial debris from the cupula,
it either results in a cure in Cup-U variant; and in the Cup-C variant, it is liable
to transform cupulolithiasis of the HSC into canalolithiasis (geotropic or apogeotropic),
which is much more amenable to the repositioning maneuvers.
