Tozzi Andrea, Castellucci Andrea, Martellucci Salvatore, Malara Pasquale, Eliezer Michael, Ferrulli Giuseppe, Ruberto Rosanna Rita, Brizzi Pasquale, Armato Enrico, Marchetti Alessio, Marchioni Daniele, Ghidini Angelo, Moratti Claudio
Department of Otorhinolaryngology-Head and Neck Surgery, University Hospital of Modena, 41125 Modena, Italy.
ENT Unit, Department of Surgery, AUSL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy.
Audiol Res. 2025 May 18;15(3):61. doi: 10.3390/audiolres15030061.
Vestibular atelectasis (VA) is a rare clinical entity characterized by a collapse of the endolymphatic space resulting in vestibular loss with the possible onset of positional and/or sound/pressure-induced vertigo. It could be idiopathic or secondary to other inner-ear diseases including Meniere's disease (MD). A collapse of the membranous labyrinth involving the semicircular canals (SCs) and the utricle represents its distinctive histopathological feature. While specific radiological patterns consistent with VA have been described on contrast-enhanced MRI with delayed acquisitions, an impairment of the blood-labyrinthine barrier (BLB) could be detected in several disorders leading to vestibular loss. We conducted a narrative review of the literature on VA focusing on the putative pathomechanisms accounting for positional and sound/pressure-induced nystagmus despite unilateral vestibular loss (UVL) in this condition, providing two novel cases of VA. Both patients presented with a clinical picture consistent with unilateral MD that rapidly turned into progressive UVL and positional and/or sound/pressure-induced vertigo. In both cases, the posterior SC was initially impaired at the video-head impulse test (vHIT) and both cervical and ocular VEMPs were initially reduced. Progressively, they developed unsteadiness with paretic spontaneous nystagmus, an impairment also for the lateral and anterior SCs, caloric hypo/areflexia and VEMPs areflexia. They both exhibited ipsilesional nystagmus to sound/pressure stimuli and in one case a persistent geotropic direction-changing positional nystagmus consistent with a "light cupula" mechanism involving the lateral SC of the affected side. A collapse of the membranous labyrinthine walls resulting in contact between the vestibular sensors and the stapes footplate could explain the onset of nystagmus to loud sounds and/or pressure changes despite no responses to high- and low-frequency inputs as detected by caloric irrigations, vHIT and VEMPs. On the other hand, the onset of positional nystagmus despite UVL could be explained with the theory of the "floating labyrinth". Both patients received contrast-enhanced brain MRI with delayed acquisition exhibiting increased contrast uptake in the pars superior of the labyrinth, suggesting an impairment of the BLB likely resulting in secondary VA. A small intralabyrinthine schwannoma was detected in one case. VA should always be considered in case of positional and/or sound/pressure-induced vertigo despite UVL.
前庭性肺不张（VA）是一种罕见的临床病症，其特征为内淋巴间隙塌陷，导致前庭功能丧失，并可能引发位置性和/或声音/压力诱发的眩晕。它可能是特发性的，也可能继发于其他内耳疾病，包括梅尼埃病（MD）。涉及半规管（SCs）和椭圆囊的膜迷路塌陷是其独特的组织病理学特征。虽然在延迟采集的对比增强磁共振成像（MRI）上已描述了与VA一致的特定放射学模式，但在几种导致前庭功能丧失的疾病中可检测到血迷路屏障（BLB）受损。我们对VA的文献进行了叙述性综述，重点关注在这种情况下尽管存在单侧前庭功能丧失（UVL），但仍可解释位置性和声音/压力诱发的眼球震颤的假定发病机制，并提供了两例VA的新病例。两名患者均表现出与单侧MD一致的临床表现，迅速发展为进行性UVL以及位置性和/或声音/压力诱发的眩晕。在这两个病例中，后半规管在视频头脉冲试验（vHIT）中最初受损，颈肌和眼肌前庭诱发肌源性电位（VEMPs）最初均降低。逐渐地，他们出现了共济失调，伴有麻痹性自发性眼球震颤，外侧和前半规管也受损，冷热试验减退/无反应以及VEMPs无反应。他们对声音/压力刺激均表现出同侧眼球震颤，在一个病例中，出现了持续的地向性方向改变的位置性眼球震颤，与涉及患侧外侧半规管的“轻嵴帽”机制一致。膜迷路壁的塌陷导致前庭感受器与镫骨足板接触，这可以解释尽管冷热试验、vHIT和VEMPs检测到对高频和低频输入无反应，但对大声响和/或压力变化仍会出现眼球震颤。另一方面，尽管存在UVL，但位置性眼球震颤的发生可以用“漂浮迷路”理论来解释。两名患者均接受了延迟采集的对比增强脑部MRI检查，显示迷路上部对比剂摄取增加，提示BLB受损，可能导致继发性VA。在一个病例中检测到一个小的迷路内神经鞘瘤。对于尽管存在UVL但仍出现位置性和/或声音/压力诱发的眩晕的情况，应始终考虑VA。
