Surgical management of acanthamoeba chorioretinitis

Abstract

Purpose: Acanthamoeba chorioretinitis is a rare manifestation of the parasitic infection, and reported cases often result in enucleation. Surgical removal of Acanthamoeba chorioretinitis has not been previously described. We report a surgical case of Acanthamoeba chorioretinitis spread from keratitis that ultimately resulted in a disease-free outcome.

Observations: A healthy 80-year-old male with a history of keratoconus requiring a penetrating keratoplasty in the fellow eye presented with a severe corneal ulcer clinically consistent with Acanthamoeba keratitis. He ultimately required a penetrating keratoplasty and improved clinically until he developed vitritis on post-operative month 1 and was diagnosed with endophthalmitis. B-scan ultrasound demonstrated vitreous opacities and a large retinal mass that reduced in size following serial intravitreal injections of antibiotics, oral antibiotics, and a limited pars plana vitrectomy. He underwent a repeat pars plana vitrectomy 6 weeks later and a retinal mass in the mid-periphery with an associated tractional retinal detachment was noted. A localized retinectomy was performed around the lesion which was excised entirely, and silicone oil was instilled. Pathology of the lesion showed acute and chronic granulomatous necrotizing inflammation with the presence of several definitive amoebic organisms and numerous cells suspicious for amoebae. The patient was maintained on oral antibiotics by the Infectious Disease Service and was disease-free 1-year post-infection.

Conclusions and importance: Acanthamoeba chorioretinitis is a rare, devastating disease and often leads to enucleation. We present a surgical case showing control of the infection utilizing a surgical retinectomy. Aggressive local therapy and a multidisciplinary approach with the Infectious Disease Service may lead to a successful outcome.

Keywords: Acanthamoeba; Chorioretinitis; Retina; Retinal detachment; Retinectomy; Vitrectomy.

Fig. 1

Clinical imaging of acanthamoeba infection. A. Slit lamp photograph of the left eye demonstrates moderate conjunctival injection with ciliary flush and diffuse corneal haze with prominent corneal neovascularization. B. Preoperative B-scan ultrasonography showed moderate vitritis, choroidal thickening, and a chorioretinal mass (arrow) measuring 4.4 mm in height. C. Vitreous cytology suggested the presence of acanthamoeba trophozoites (blue arrow) and acute inflammation with lymphocytes (red arrow). Hematoxylin and eosin, original magnification 300x. D. After a core vitrectomy and intravitreal injection of broad-spectrum antibiotics, ultrasonography showed reduced vitritis, improved choroid thickening, and reduced retinal mass size. . (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

Postoperative course after retinal biopsy where histopathological examination of retinal biopsy confirmed acanthamoeba cysts and trophozoites. A. Surgical drawing illustrates the inferonasal retinal mass in the mid-periphery with a tractional retinal detachment (blue) secondary to proliferative pre-retinal membranes (green). Pre-retinal membranes were also noted in the temporal macula. A large retinectomy to remove traction from the retinal mass was performed from 5:30 o'clock to 9:00 o'clock (red line) and the retinectomy edge was sealed with endolaser. B. Vitreous biopsy cytospin preparations showed lymphocytes, neutrophils and histiocytes. Rare cells had a morphology suspicious for amoeba (blue arrow). Hematoxylin and eosin, original magnification 300x. C. A retinal biopsy showed necrotic tissue with fragments of neurosensory retina and inflammatory cells including epithelioid histiocytes, lymphocytes, and neutrophils. Rare cells showed a morphology consistent with the trophozoite form of Acanthamoeba (red arrowheads). Wright-Giemsa stain, original magnification 300x. D. An ultra-widefield color photograph of the left eye on post-operative month 1 demonstrates attached retina under silicone oil. The retinectomy edge was flat (white arrows), and there was mild hemorrhage in the macula (white arrowhead). E. Spectral-Domain Optical Coherence Tomography of the left eye shows improvement of cystoid macular edema over the course of six months. F. An ultra-widefield color photograph of the left eye on post-operative month 6 demonstrates attached retina under silicone oil. The retinectomy edge remained flat (white arrows), and hemorrhages had resolved. No recurrence of retinitis was noted. G. Slit lamp photograph of the left eye shows a clear corneal graft with interrupted nylon sutures, and a quiet anterior chamber. . (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)