A CHALLENGING JOURNEY THROUGH THE DIAGNOSIS AND TREATMENT OF ACANTHAMOEBA KERATITIS

To report a case of delayed diagnosis of Acanthamoeba keratitis, complicated by chronic scleritis and persistent uveitis with final microbiological diagnosis following enucleation.

Clinical records and slit-lamp photos review, laboratory investigations, imaging and histological review of a case that resulted negative for Acanthamoeba on multiple testing.

Results: A 76 years old female with previous history of right Bell's palsy and monthly contact lens wear for hypermetropia presented with a red and painful right eye for 5 days, a clear cornea, no visual loss, no scalp tenderness, no jaw claudication. She reported similar self-resolving episodes affecting left eye during the previous 6 months. After the first month of topical antibiotics and lubricants she developed an epithelial defect that progressively enlarged to 5x7mm and became associated with anterior uveitis, corneal oedema, progressive stromal neovascularisation, hypopyon, intense pain and light sensitivity. She underwent vitreous and anterior chamber biopsy, the corneal biopsy resulted negative on three occasions, the in vivo confocal microscopy resulted negative. Due to the persistent uveitis and intense ocular pain, the patient was initiated on oral prednisolone and methotrexate. 13 months after presentation, due to the progressive loss of vision and persistence of pain, the patient underwent enucleation and histology. The immunohistochemistry showed acanthamoeba cysts in the posterior cornea associated with reactive scleritis.

This case shows many important learning points on the clinical management of this infection and the challenges of false negative diagnostic testing.