Abstract
Purpose:
The diagnosis and treatment of Acanthamoeba keratitis (AK) are still a major challenge for ophthalmologists due to the variability of cases. Aim of this examination was to evaluate patients with suspicion of AK regarding confocal microscopy (CM), histocytology of corneal scrapings, and polymerase chain reaction (PCR) using corneal cells.
Methods:
The ophthalmological appearance of AK will be compared with findings in CM, corneal scraping and PCR tests in a retrospective, single centre study. CM was only accepted positive if one or more double walled cysts could be detected and corresponded with the morphology of Acanthamoeba cysts in microscopy (HE staining). CM used Rostock cornea module of Heidelberg retina tomograph and was applied by two investigators. We evaluated 46 patients, who had the suspected diagnosis of AK between 2003 and 2012.
Results:
CM performed in 18 cases resulted positive in 8 cases (44%), corneal scraping resulted positive in 29 of 31 cases tested (94%), and PCR was positive one times of 11 cases tested (9%). Of 46 patients tested 33 were positive for at least one of the applied diagnostic procedures. The median age of AK positive patients was 40 years (2-75 years). The follow up was in median 18 months (2 to 102 months). 17 patients have worn contact lenses. The duration of symptoms at the first visit in our hospital was in average 33 weeks. The period of time between the first visit and AK diagnosis was 23 days. 11 patients had additional corneal diseases like herpetic, bacterial or fungal keratitis, proven by microbiological tests. 21 of the AK-patients underwent surgical therapy. One or more amniotic membrane transplantations were performed in 11 cases. A keratoplasty had to be done in 12 eyes; a re-keratoplasty in 6 eyes. Cryotherapy was performed in 7 eyes. At the end of follow up 5 eyes had to be enucleated, as result of devastating ocular infection.
Conclusions:
The suspected diagnosis of AK could be confirmed in 71%. A long period of time often lays between the first symptoms and the final diagnosis of AK due to difficult diagnostics and variable symptoms. A prolonged as well as conservatively and surgically challenging therapy is often needed. In our case series 15 % had to be enucleated despite all the care taken. Objective parameters are needed for an improvement of diagnostic and treatment approach in AK.
Keywords: 402 Acanthamoeba •
573 keratitis •
418 amoeba