Acanthamoeba Endophthalmitis And Scleritis In A Refractory Infectious Keratitis

Acanthamoeba keratitis (AK) is a chronic and predominantly contact lens-related corneal infection caused by the ubiquitous Acanthamoeba amoeba. Diagnosis of the infection presents challenges in a clinical setting, and treatment is frequently refractory. Although uncommon, intraocular penetration can ensue, culminating in fatal consequences as a result of the potential dissemination of the pathogen to the central nervous system.

A patient with refractory AK treated in Cornea Department in Centro Hospitalar Universitário do São João, Porto, Portugal.

A healthy 23 year-old-woman presented to our department with complaints of redness and pain in her right eye (OD) that had been present for 8 days. She used soft daily contact lenses. In biomicroscopy, an epithelial ring was observed in a pseudodendritic pattern with no underlying stromal involvement. We collected cornea swabs for mycobacteriology cultures, as well as for polymerase chain reaction (PCR) Acanthamoeba, which confirmed the diagnosis of AK. The patient began treatment with topical chlorhexidine and propamidine 6 times daily. After 13 months of intensive medical therapy, the AK worsened, resulting in a loss of cornea transparency. 

A reinforcement of chlorhexidine and propamidine (each hour) was initiated and she was submitted to her first penetrating keratoplasty (PK).The condition persisted and frequent flares were observed over the next 12 months. The patient underwent four more PK, a facectomy and began rescue oral treatment with 50 mg miltefosine twice a day. Despite these measures, progression to scleritis and endophthalmitis occurred. A vitrectomy pars plana was performed and vitreous samples were collected. The presence of Acanthamoeba in vitreous was confirmed by PCR. Due to concerns about extraocular spread, she underwent evisceration of the OD. Currently there is no radiological evidence of central nervous system infectious dissemination.

In our case, despite optimized medical therapy and multiple penetrating keratoplasties, the patient's AK worsened and progressed to scleritis and endophthalmitis, resulting in the need for evisceration of the affected eye. This case mirrors the challenge in managing this pathology as well as the breadth of infrequent and highly dangerous presentations that demand vigilant awareness from ophthalmologists.