良性陣發性位置性眩暈

Benign Paroxysmal Positional Vertigo

良性陣發性位置性眩暈（benign paroxysmal positional vertigo, BPPV）是頭暈最常見的病因。Dix-Hallpike maneuver可診斷約佔耳石症8成的後半規管耳石症（posterior canal BPPV, PC-BPPV），患耳的耳石因重力之故，帶動內淋巴液流動，致壺腹（ampulla）的頂帽（cupula）偏移，誘發出向上併廻旋性眼振，Epley maneuver和Sémont maneuver等耳石復位術是治療首選。平躺下左右側躺檢查（supine to head-lateral test）可診斷約佔耳石症2成的水平半規管耳石症（horinzotal canal BPPV, HC-BPPV），出現向地眼振為管耳石型水平半規管耳石症，出現逆地眼振為頂帽沉石型水平半規管耳石症。治療方式有持續姿勢法（forced prolonged position, FPP），即讓病患躺向眼振較弱側連續10-12小時，難以承受長時間側躺者可採用其它復位術治療，如barbecue maneuver和Gufoni maneuver。前半規管耳石症（anterior canal BPPV, AC-BPPV）最為罕見，Dix-Hallpike maneuver呈向下眼振，治療方式毋須考慮患耳為何側，均採頭仰懸復位術（deep head hanging maneuver）。

Benign paroxysmal positional vertigo (BPPV) is the most common cause of dizziness. Posterior canal BPPV (PC-BPPV) accounts for about 80% of all types of BPPV, can be diagnosed by Dix-Hallpike maneuver, otolith can trigger flow of endolymphatic fluid by gravity, then cause deviation of cupula and induce upward rotatory nystagmus. PC-BPPV can be treated by canalith repositioning procedure, such as Epley maneuver and Sémont maneuver. Horizontal canal BPPV (HC-BPPV) accounts for about 20% of all types of BPPV, can be diagnosed by supine to head-lateral test, geotropic nystagmus means canalithiasis of HC-BPPV, apogeotropic nystagmus means cupulolithiasis of HC-BPPV. HC-BPPV can be treated by forced prolonged position (FPP), let the patient lie to the weaker side of nystagmus for 10~12 hours continuously, if the patient cannot endure long term side lying then choose other methods, such as barbecue maneuver and Gufoni maneuver. Anterior canal BPPV (AC-BPPV) is very rare, downbeat nystagmus can be induced by Dix-Hallpike maneuver, can be treated by deep head hanging maneuver no need to consider which side is lesion side.