Afonso Joana M, Falcão Manuel, Schlichtenbrede Frank, Falcão-Reis Fernando, Silva Sérgio Estrela, Schneider Till M
Department of Ophthalmology, São João University Hospital, Porto, Portugal.
Department of Ophthalmology, University Hospital Mannheim, Mannheim, Germany.
Front Neurol. 2017 May 1;8:172. doi: 10.3389/fneur.2017.00172. eCollection 2017.
Characterized by a progressive onset of gait disturbances, dementia, and urinary incontinence, idiopathic normal pressure hydrocephalus (iNPH) is considered a rare, but under-diagnosed disease. Non-invasive diagnostic markers are still insufficient to enable the diagnosis of iNPH with certainty and yet early treatment with ventriculoperitoneal (VP) shunting can reverse symptoms and stop disease progression. Vascular circulation abnormalities in iNPH may be reflected by changes in subfoveal and peripapillary choroidal thickness (PPChT). This study uses spectral domain-optical coherence tomography (SD-OCT)-based measures of retinal and choroidal thickness to test this hypothesis and to assess ophthalmological non-invasive markers for iNPH.
Twelve patients who displayed neurological and neuroradiological characteristics of iNPH were subject to a full ophthalmological examination including enhanced depth imaging (EDI) SD-OCT. Of the 12 included iNPH patients, 6 had undergone VP shunting with beneficial outcome. Parameters studied with EDI SD-OCT were macular retinal thickness (MT), subfoveal choroidal thickness (SFChT), retinal nerve fiber layer thickness (RNFL), and PPChT. Results were compared with 13 healthy, age-matched controls.
Macular thickness and RNFL and MT values of iNPH patients did not reflect atrophy. Non-shunted iNPH patients showed significantly lowered median PPChT and SFChT values compared to healthy controls. Shunted iNPH patients displayed a significantly higher median PPChT and SFChT compared to non-shunted iNPH patients. SFChT and PPChT values in shunted patients were not significantly different to values in healthy controls.
Although limited by small sample size, SD-OCT measures in this study reveal significant changes of choroidal thickness and support the hypothesis of choroidal susceptibility to hemodynamic alterations in iNPH. Non-shunted iNPH patients in this study show choroidal thinning in combination with normal RNFL and MT values. In addition to neurological and neuroradiological exams, this pattern may aid in the challenging diagnosis of iNPH.
特发性正常压力脑积水（iNPH）的特征为步态障碍、痴呆和尿失禁逐渐出现，被认为是一种罕见但诊断不足的疾病。非侵入性诊断标志物仍不足以确诊iNPH，然而早期进行脑室腹腔（VP）分流治疗可逆转症状并阻止疾病进展。iNPH中的血管循环异常可能通过中心凹下和视乳头周围脉络膜厚度（PPChT）的变化得以反映。本研究采用基于光谱域光学相干断层扫描（SD-OCT）的视网膜和脉络膜厚度测量方法来验证这一假设，并评估iNPH的眼科非侵入性标志物。
对12例表现出iNPH神经学和神经放射学特征的患者进行全面眼科检查，包括增强深度成像（EDI）SD-OCT。在这12例纳入研究的iNPH患者中，6例已接受VP分流且效果良好。通过EDI SD-OCT研究的参数包括黄斑视网膜厚度（MT）、中心凹下脉络膜厚度（SFChT）、视网膜神经纤维层厚度（RNFL）和PPChT。将结果与13名年龄匹配的健康对照进行比较。
iNPH患者的黄斑厚度、RNFL和MT值未反映出萎缩情况。与健康对照相比，未分流的iNPH患者的PPChT和SFChT中值显著降低。与未分流的iNPH患者相比，分流后的iNPH患者的PPChT和SFChT中值显著更高。分流患者的SFChT和PPChT值与健康对照的值无显著差异。
尽管本研究受样本量小的限制，但SD-OCT测量结果显示脉络膜厚度有显著变化，并支持iNPH中脉络膜对血流动力学改变敏感的假设。本研究中未分流的iNPH患者表现出脉络膜变薄以及正常RNFL和MT值。除神经学和神经放射学检查外，这种模式可能有助于iNPH的挑战性诊断。
