Thomas P A
Institute of Ophthalmology, Joseph Eye Hospital, Tiruchirapalli, India.
J Med Vet Mycol. 1994;32(4):235-56. doi: 10.1080/02681219480000321.
Mycotic keratitis, an important ophthalmologic problem, especially in outdoor workers in the tropics, is frequently caused by filamentous fungi such as species of Fusarium, Aspergillus and Curvularia, and by yeast-like fungi such as Candida. A rapid, presumptive diagnosis can be made by recognition of certain typical clinical features and by direct microscopic detection of fungi in corneal scrapings stained by various methods. The diagnosis is confirmed by culture. In difficult cases, microbiological studies on corneal biopsies or histopathological studies on tissue sections may need to be performed. The use of fluorescein-conjugated lectins and similar diagnostic tools is aimed at providing rapid, species-specific detection of fungi in corneal tissue. Antifungal therapy must be instituted as soon as the diagnosis is made. While keratitis due to Aspergillus, Candida and dematiaceous fungi can be successfully treated by many of the currently available polyenes and azoles, the treatment of Fusarium keratitis still frequently requires the use of pimaricin or econazole. Treatment by the oral and parenteral routes may prove useful in severe mycotic keratitis. Surgery may need to be performed on cases unresponsive to medical therapy or where serious complications are likely to occur. The pathogenesis of mycotic keratitis appears to involve agent factors, such as invasiveness and toxigenicity, and host factors, such as trauma and intrinsic defects in resistance. Areas for future research include the development of rapid, species-specific diagnostic aids, of broad-spectrum antifungal compounds active by various routes, and of therapeutic modalities which act on the fungus and on molecules involved in the pathogenesis of the condition.
真菌性角膜炎是一个重要的眼科问题，尤其在热带地区的户外工作者中，常由丝状真菌如镰刀菌属、曲霉菌属和弯孢霉菌属，以及酵母样真菌如念珠菌引起。通过识别某些典型临床特征以及直接显微镜检测经各种方法染色的角膜刮片中的真菌，可做出快速的初步诊断。通过培养来确诊。在疑难病例中，可能需要对角膜活检组织进行微生物学研究或对组织切片进行组织病理学研究。使用荧光素结合凝集素及类似诊断工具旨在对角膜组织中的真菌进行快速、种属特异性检测。一旦做出诊断，必须立即开始抗真菌治疗。虽然由曲霉菌、念珠菌和暗色真菌引起的角膜炎可通过许多现有的多烯类和唑类药物成功治疗，但镰刀菌性角膜炎的治疗仍常常需要使用匹马霉素或益康唑。对于严重的真菌性角膜炎，口服和胃肠外途径治疗可能有效。对于药物治疗无反应或可能发生严重并发症的病例，可能需要进行手术。真菌性角膜炎的发病机制似乎涉及病原体因素，如侵袭性和产毒性，以及宿主因素，如创伤和内在抵抗力缺陷。未来的研究领域包括开发快速、种属特异性诊断辅助工具；开发通过各种途径具有活性且有广谱抗真菌作用的化合物；以及开发作用于真菌和该疾病发病机制中涉及分子的治疗方法。
