Department of Otolaryngology, Suita Municipal Hospital, Osaka University School of Medicine, Osaka, Japan.
Otol Neurotol. 2010 Feb;31(2):250-5. doi: 10.1097/MAO.0b013e3181cabd77.
To investigate the occurrence rate, prognosis, and inner ear abnormality in intractable benign paroxysmal positioning vertigo (BPPV).
A prospective study.
Tertiary referral university hospital.
Intractable BPPV was defined in case of either a persistent nystagmus or a frequent relapse each lasting more than 1 year after the initial diagnosis.
T2-weighted 3-dimensional fast imaging employing steady-state acquisition sequences of magnetic resonance imaging (MRI) were reconstructed 3-dimensionally for 13 intractable BPPV patients and 14 control volunteers.
Transition and relapse of nystagmus were monitored. Semicircular canals were evaluated for a stenosis or filling defect (obturation).
Eighteen patients (4 with posterior canal type, 2 with horizontal canal type with geotropic nystagmus, and 12 with apogeotropic nystagmus) fulfilled the above criteria for intractability among 495 BPPV patients. The occurrence rate of intractable BPPV was 3.6%. Also, the rate of nystagmus transition was significantly higher in patients with geotropic nystagmus and the posterior canal type (100%) compared with those with apogeotropic nystagmus (33.3%). Of the 13 intractable BPPV patients who underwent MRI, 11 (84.6%) had a total of 23 canals with abnormal appearance (29.5%), showing a significantly higher incidence compared with controls. There was no correlation between the affected canal diagnosed by MRI and the type of nystagmus.
The low incidence of nystagmus transition in patients with apogeotropic nystagmus suggests a difference in pathophysiology between apogeotropic nystagmus and other types of BPPV. Stenosis and filling defect (obturation) of canals on MRI, which would indicate an innate narrowing and/or an otoconial jam of the semicircular canal, may account for the intractability of BPPV.
探讨难治性良性阵发性位置性眩晕（BPPV）的发生率、预后及内耳异常。
前瞻性研究。
三级转诊大学医院。
难治性 BPPV 的定义为初始诊断后持续眼震或频繁复发，持续时间均超过 1 年。
采用稳态采集序列的 T2 加权 3 维快速成像对 13 例难治性 BPPV 患者和 14 例对照志愿者进行 3 维重建。
监测眼震的转变和复发。评估半规管狭窄或充盈缺损（闭塞）。
在 495 例 BPPV 患者中，有 18 例（4 例后半规管型、2 例向地性水平半规管型伴眼震、12 例背地性眼震）符合难治性标准。难治性 BPPV 的发生率为 3.6%。此外，向地性眼震和后半规管型患者的眼震转变率明显高于背地性眼震患者（100%比 33.3%）。在接受 MRI 的 13 例难治性 BPPV 患者中，11 例（84.6%）共 23 条半规管出现异常（29.5%），明显高于对照组。MRI 诊断的受累半规管与眼震类型之间无相关性。
背地性眼震患者眼震转变发生率低，提示背地性眼震与其他类型 BPPV 的病理生理学不同。MRI 显示的半规管狭窄和充盈缺损（闭塞），可能提示半规管先天狭窄和/或耳石嵌顿，可能是 BPPV 难治性的原因。
