Die Akanthamöbenkeratitis – ein seltenes und oft spät diagnostiziertes Chamäleon

 

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Zusammenfassung

Der Anteil der Kontaktlinsenträger bei Patienten mit Akanthamöbenkeratitis liegt bei 83 – 93 %. Zur Diagnosestellung einer Akanthamöbeninfektion werden heute – aufgelistet in absteigender Reihenfolge bezüglich Sensitivität und Spezifität – Polymerase-Kettenreaktion (PCR), konfokale Biomikroskopie, In-vitro-Kultivierung und histopathologische Untersuchungen eingesetzt. Das typische Bild der Akanthamöbenkeratitis wird durch pseudodendritiforme Epitheliopathie, Perineuritis, Ringinfiltrat oder multifokale stromale Infiltrate geprägt. Des Weiteren kann eine Limbitis mit Infiltration der Konjunktiva oder eine Uveitis anterior auftreten. Informationen über die Effektivität und Sicherheit der medikamentösen und chirurgischen Therapie konnten bisher nur aus publizierten Fallserien gezogen werden und wurden noch nicht durch randomisierte kontrollierte klinische Studien abgesichert. Wird die Diagnose rechtzeitig gestellt, kann eine Akanthamöbenkeratitis durch dreifache medikamentöse Therapie (Polyhexamid, Propamidinisoethionat, Neomycin) behandelt werden. Die Therapiedauer beträgt jedoch auch bei rechtzeitigem Beginn bis zu einem Jahr. Bei Therapieresistenz kann eine Kryotherapie, Amnionmembrantransplantation, Crosslinkingtherapie oder eine therapeutische Keratoplastik notwendig werden. Die Prognose einer Keratoplastik verbessert sich, wenn mindestens drei Monate lang vor der Operation keine Infektionszeichen mehr bestanden.

Abstract

In 83 – 93 % of the cases of acanthamoeba keratitis the patients are contact lens wearers. Acanthamoeba keratitis is diagnosed – with descending order of sensitivity and specificity – through polymerase chain reaction (PCR), confocal biomicroscopy, in-vitro cultivation and histopathological examination. The typical clinical appearance of acanthamoeba keratitis includes pseudodendritic epitheliopathy, perineuritis, ring infiltrate or multifocal stromal infiltrates and in some cases limbitis with infiltration of the conjunctiva and/or sterile anterior uveitis. Information on reliability and efficacy of the medical/surgical therapy for acanthamoeba keratitis has only been published for case series and It has not been verified through randomised controlled clinical studies so far. By early diagnosis, using triple-topical therapy (polyhexamid, propamidinisoethionat, neomycin) acanthamoeba keratitis often heals appropriately. However, even if diagnosed early, topical therapy should be continued for 1 year. In therapy-resistant cases cryotherapy, amniotic membrane transplantation, cross-linking therapy, and therapeutic keratoplasty are performed. The prognosis of keratoplasty following acanthamoeba keratitis is more favourable when there were no signs of infection at least during the preceding 3 months.

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