Benign paroxysmal positional vertigo (BPPV) is most closely associated with which mechanism?

Benign paroxysmal positional vertigo (BPPV) is most closely associated with which mechanism?

• A. Otoconia displaced into the semicircular canals
• B. Inflammation of the cochlea
• C. Tumor of the vestibular nerve
• D. Migraine-related vertigo

Answer: (A)

BPPV is caused by loose otoconia from the utricle drifting into one of the semicircular canals, most commonly the posterior canal. These crystals make the canal abnormally sensitive to head position. When you move the head, gravity moves the crystals, causing abnormal endolymph flow and stimulation of the hair cells in the canal. This produces brief, intense vertigo and often a brief nystagmus that occurs with specific positional changes, such as rolling in bed or looking up. This mechanism is distinct from the other possibilities: inflammation of the cochlea would affect hearing and balance more diffusely (labyrinthitis), a vestibular nerve tumor tends to cause gradual, persistent imbalance with possible hearing loss, and migraine-related vertigo is not due to displaced otoconia in the canals.

BPPV is caused by loose otoconia from the utricle drifting into one of the semicircular canals, most commonly the posterior canal. These crystals make the canal abnormally sensitive to head position. When you move the head, gravity moves the crystals, causing abnormal endolymph flow and stimulation of the hair cells in the canal. This produces brief, intense vertigo and often a brief nystagmus that occurs with specific positional changes, such as rolling in bed or looking up.

This mechanism is distinct from the other possibilities: inflammation of the cochlea would affect hearing and balance more diffusely (labyrinthitis), a vestibular nerve tumor tends to cause gradual, persistent imbalance with possible hearing loss, and migraine-related vertigo is not due to displaced otoconia in the canals.