Canalith

Canalith is a term used in otology to refer to small calcified particles, typically otoconia, that originate in the inner ear’s utricle and can become dislodged into one of the semicircular canals. In benign paroxysmal positional vertigo (BPPV), canaliths may migrate into the posterior canal, where they move with head changes and disturb the normal flow of endolymph, leading to brief episodes of vertigo and nystagmus. The condition is often described as canalithiasis when the free-moving particles cause symptoms, as distinct from cupulolithiasis, in which particles adhere to the cupula.

Diagnosis is usually based on clinical history and positional testing, with the Dix-Hallpike maneuver commonly used to elicit vertigo and a characteristic pattern of nystagmus. Treatment focuses on repositioning the canaliths to the utricle, using canalith repositioning procedures such as the Epley maneuver or the Semont maneuver. These maneuvers aim to move the particles out of the canal and into a location where they no longer provoke symptoms. Most patients experience relief after one or a few sessions, though recurrences can occur.

Etymology: canalith combines canal, referring to the semicircular canal, with lith, meaning stone. The term is primarily encountered in clinical discussions of BPPV and otolith-related vertigo.

See also: Benign paroxysmal positional vertigo, otolith, semicircular canal, endolymph, Epley maneuver.