常见致病真菌所致角膜炎的激光扫描共焦显微镜图像特点分析

The features of in vivo laser confocal microscope images of frequent fungal keratitis

背景真菌性角膜炎仍是中国主要的感染性眼病，传统的确诊方法主要是角膜刮片后进行菌种培养。激光扫描共焦显微镜检查是近年来使用的无创性活体眼表检查的方法，但目前关于真菌性角膜炎病灶区相关检查特点的研究工作尚不够系统和完善。目的研究和分析中国常见的4种致病菌引起的真菌性角膜炎的激光扫描共焦显微镜检查特点。方法采用回顾性研究设计，对2007年1月至2011年11月在南京军区南京总医院初诊且进行激光扫描共焦显微镜检查的65例真菌性角膜炎患者的临床资料进行分析，患者均为单眼患病。所有患眼均进行角膜真菌的实验室培养和激光扫描共焦显微镜检查，对不同菌种引起的真菌角膜炎激光扫描共焦显微镜图像特点进行分析，主要包括菌丝的特点、孢子的分布及菌丝与病灶周围组织反映的关系，并总结激光扫描共焦显微镜下真菌菌丝与其他角膜组织的鉴别要点。结果角膜感染菌的实验室培养结果显示，本研究中纳入的患眼中镰刀菌角膜感染者占63．0％，曲霉菌感染者占16．9％，念珠菌感染者占3．0％，链格孢霉菌感染者占4．6％。激光扫描共焦显微镜检查显示，镰刀菌感染性角膜炎病灶中的菌丝在角膜浅基质层呈树枝样高反光，而在深基质层表现为线型，病灶区炎性细胞较少；念珠菌感染性角膜炎病灶中的假菌丝位于角膜浅、中基质层，有散在的孢子和炎性细胞浸润，基质纤维增生活跃；曲霉菌感染病变区的菌丝呈蠕虫状，形状较镰刀菌细且短；链格孢霉菌感染病灶区的菌丝长、直且粗大，并有球形厚垣孢子位于菌丝顶端。激光扫描共焦显微镜下各种真菌性角膜炎病灶区的菌丝与角膜上皮下神经丛、树突状细胞、角膜的增生纤维等均表现为高反射，但其形状、分布及走行均有所不同。结论真菌菌丝是诊断和鉴别真菌性角膜炎感染菌属的主要依据，激光扫描共焦显微镜可在活体提供有用的相关信息，为真菌性角膜炎的早期诊断和治疗提供可靠依据。

Background Fungal keratitis is one of primary infectious ocular diseases in China. Conventional diagnostic method is fungal cultivation. In vivo laser confocal microscope is a noninvasive examination of ocular surface. However,the study on features of in vlvo laser confocal microscope images of frequent fungal keratitis is still not thorough. Objective This study was to analyze laser confocal microscope imaging features of four typical fungal keratitis. Methods The clinical data of 65 eyes from 65 patients with fungal keratitis were retrospectively analyzed. The patients were initially diagnosed in Nanjing General Hospital of Nanjing Military Command PLA from January 2007 to November 2011, and laser confocal microscope examination of ocular surface and fungal cultivation were performed. The characteristics of laser confocal microscope images were investigated,including shape and type of hypha,distribution of spores and the relationship of hypha with lesion. The differentiation between fungal hypha and other corneal tissues was summarized. Results Fungal cultivation showed that among the 65 patients,Fusarium, Aspergillus,Candida and Alternaria were common pathogenic fungus with the infected proportion 63.0%, 16.9%, 3.0% and 4.6% ,respectively, and 12. 5% patients were infected by other fungus. In the images of laser eonfocal microscope,hyphae of Fusarium presented the branch-like high reflective structure in the corneal superficial stromal layer and thinning line shape in the deep stromal layer. Few inflammatory cells were found. The peudohyphae and spores from Candida were seen in corneal superficial and mid stroma layers, with few inflammatory cells and many proliferating stromal fibers in the lesions. The hyphae of Aspergillus presented worm-like, showing the thinner and shorter shapes in comparison with those of Candida. The hyphae of Alternaria were long,straight and thick in shape, and spherical chlamydospores were found on the hyphal tip. The hyphae, subepithelial plexus, dendritic ceils, fibrosis of the cornea all showed high reflection under the laser confocal microscope, but evidently differences appeared in shape,distribution and course in corneas. Conclusions Hyphae are the main basis to diagnose fungal keratitis and differentiate fungi. As a non-invasive examination method,laser confocal microscope can provide useful information for the early diagnosis and treatment of fungal keratitis in vivo.