Anterior canal BPPV

I love vertigo. Remember that 10% of your average grandmothers out there actually harbour some stones in their canals [Oghalai 2000]. Here are (in order of my subjectively experienced prevalence) the most important BPPV syndromes:

  • posterior canal benign positional vertigo (pBPPV) with canalolithiasis
  • horizontal (aka lateral) canal benign positional vertigo (hBPPV) with canalolithiasis
  • hBPPV with cupulolithiasis
  • Sitting-up vertigo (an abortive form of BPPV?)
  • anterior canal benign positional vertigo (aBPPV) with canalolithiasis
  • pBPPV with cupulolithiasis
  • aBPPV with cupulolithiasis

We covered hBPPV and pBPPV in the past and today approach the vertex of vertigo: anterior canal canalolithiasis. I myself have not often diagnosed it, not the least because I did not know enough about it. Since the diagnostic maneuver is simple to integrate into my screening procedures, I added it to my repertoire recently and found some instances of aBPPV already.

Here is my standard program in positional vertigo (a melange of Asprella, Dix-Hallpike and others):

  • If the history is unclear, I start by lying the patient straight back and watch the eyes (Asprella’s maneuver). If a pure horizontal nystagmus is evoked – go on the head roll test. If a torsional component is seen then go on to Dix-Hallpike on the respective side. If no nystagmus comes up let the head hang some more (the straight head hanging test). If nothing is evoked, put the head back in neutral and do the head roll test to both sides.
  • If nothing has come up yet, do Dix-Hallpike on the side that fits the patients’ history best. If no side can be determined from the history, I start right. I do DH with head turned and reclined and lying on the back (not as some perform it to the side).
  • I recommend Frenzel glasses (for BPPV rather than vor Neuritis, where it can be substituted for a bright light and a hand) or freeze frame on an iPhone.

Now back to the anterior canal. Here are some pearls about it – as gathered from the literature.

  • It might be rare but that is partly due to being overlooked.
  • It can arise during treatment of pBPPV
  • The torsional component of DH nystagmus in aBPPV is less pronounced than in pBPPV so that it mimicks central positional downbeat nystagmus.
  • Conversely sometimes the vertical component is less pronounced so that it mimicks pBPPV.
  • aBPPV often causes nystagmus on both Dix-Hallpike-sides
  • The more the head hangs the better (which is strange as the AC is far from the sagittal plane)
  • It is not so much the speed of the movement but the final position that is the problem
  • Possibly there are more cupulolithiasis cases than canalolithiasis in aBPPV than in pBPPV

I sometimes find it hard to distinguish PC from AC in the DH test, so I recommend the head hanging test to specifically diagnose AC. If you want to diagnose it during DH, you have to watch out for the vertical component of the nystagmus, which often is hard to spot, resulting in low percentages of aBPPV in BPPV. Using VNG improves the rate considerably, but that is not helpful in the ER setting.

As for therapy, the modified Epley is probably enough – if you find the proper side to treat [Jackson et al. acBPPV. Otology and Neurotology 2007].  Yet there is this cool maneuver that does not require this information, since it just works in the sagittal plane.

References:

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