Elhardt Carolin, Schweikert Romina, Hartmann Lennart Maximilian, Vounotrypidis Efstathios, Kilani Adnan, Wolf Armin, Wertheimer Christian Maximilian
Department of Ophthalmology, University Hospital Ulm, Prittwitzstrasse 43, Ulm, 89075, Germany.
J Ophthalmic Inflamm Infect. 2023 May 2;13(1):23. doi: 10.1186/s12348-023-00345-2.
Acanthamoeba keratitis is often misdiagnosed at disease onset. This study presents data to confirm the diagnosis using calcofluor white (CFW) staining.
Forty three patients were retrospectively included who presented to the Department of Ophthalmology at the University Hospital Ulm with keratitis between 2000 and 2022. Condition positive cases were diagnosed based on the typical clinical presentation of Acanthamoeba keratitis with a positive polymerase chain reaction (PCR). Condition negative were patients with ulcers due to other causing pathogens with a negative Acanthamoeba PCR result. The condition was compared with the CFW test results.
After symptom onset, time until presentation was 17 ± 12 days and until diagnosis 27 ± 13 days in the 15 condition positive patients. Among the 35 patients with additional CFW test, 7 patients were condition positive and 28 negative. 5 of the 7 patients were true positive, 2 were false negative. In the 28 condition negative patients, 1 was false positive. Sensitivity of CFW was 71% and specificity 96%. The positive PCR results were available 3.4 ± 2.3 days after corneal scraping, the positive CFW test results on the same day in each case.
Our data demonstrate that diagnosis of Acanthamoeba keratitis remains difficult and therapy is initiated late. A positive CFW test confirms the diagnosis as there are almost no false positive results and it was available faster than PCR. In case of a negative CFW test, Acanthamoeba keratitis cannot be ruled out because of a high false negative rate.
棘阿米巴角膜炎在疾病发作时常常被误诊。本研究提供数据以证实使用荧光增白剂（CFW）染色进行诊断。
回顾性纳入了2000年至2022年间在乌尔姆大学医院眼科就诊的43例角膜炎患者。确诊阳性病例基于典型的棘阿米巴角膜炎临床表现及聚合酶链反应（PCR）阳性结果。确诊阴性为因其他致病病原体导致溃疡且棘阿米巴PCR结果为阴性的患者。将确诊情况与CFW检测结果进行比较。
在15例确诊阳性患者中，症状出现后至就诊时间为17±12天，至诊断时间为27±13天。在另外进行CFW检测的35例患者中，7例确诊阳性，28例确诊阴性。7例患者中有5例为真阳性，2例为假阴性。在28例确诊阴性患者中，1例为假阳性。CFW的敏感性为71%，特异性为96%。角膜刮片后3.4±2.3天可获得阳性PCR结果，而阳性CFW检测结果在每种情况下均于同一天获得。
我们的数据表明，棘阿米巴角膜炎的诊断仍然困难，且治疗开始较晚。CFW检测结果阳性可确诊，因为几乎没有假阳性结果，且其结果比PCR更快获得。若CFW检测结果为阴性，由于假阴性率高，不能排除棘阿米巴角膜炎。
