Anti-vascular Endothelial Growth Factor for Choroidal Neovascularization Associated with Toxoplasmosis: A Case Series

The purpose of the study was to evaluate the efficacy and safety of intravitreal anti-vascular endothelial growth factor (anti-VEGF) in treatment of choroidal neovascularization (CNV) secondary to toxoplasmic retinochoroiditis in five patients. After six months the CNV resolved as confirmed by fluorescein angiography and optical coherence tomography (OCT) in all patients. The visual acuity improved from mean 20/400 to 20/80 and Central Macular Thickness (CMT) decreased from 390 μm to 253 μm, which was maintained till the last follow-up visit.


Introduction
Treatment modalities for choroidal neovascularization (CNV) due to ocular toxoplasmosis include laser photocoagulation, surgery, corticosteroids, and verteporfin therapy. Intravitreal injection of Antivascular endothelial growth factor (anti-VEGF ) in the treatment of CNV due to other conditions appears to be an effective and safe therapeutic option. We report 5 cases of successful treatment with anti-VEGF for symptomatic CNV due ocular toxoplasmosis.

Methods
The Isfahan University Medical Center approved this study. Our study population consisted of 5 patients with CNV due to ocular toxoplasmosis (3 women, 2 men) with a mean (SD) age of 27.2 (7.1) years, all with documented notes suggested of clinical and serological diagnosis of toxoplasmosis retinichoriditis and had been treated with oral sulfadiazine and pyrimethamine, along with systemic steroids at least 6 months before referral to our clinic.
All patients received a complete ophthalmologic evaluation. The anterior chamber and vitreous cavity were quiet in all patients. No signs suggestive of age-related macular degeneration were found. Fluorescein (FA) criteria included evidence of leakage caused by CNV (100% classic without an occult component) secondary to ocular toxoplasmosis and presence of intraretinal or subretinal fluid documented by optical coherence tomography (OCT). Intravitreal anti-VEGF treatment was recommended for all patients (bevacizumab, 1.25 mg for 4 eyes and ranibizumab 0.5 mg for one eye).

Results
CNV was inactive in all eyes after Intravitreal anti-VEGF treatments with an absence of leakage demonstrated by fluorescein angiography, complete disappearance of exudative signs and reduction of retinal thickness shown by OCT (Figure 1).

Discussion
CNV formation secondary to toxoplasmosis retinochoroiditis is a rare event with a poor visual prognosis. Treatment modalities for CNV secondary to toxoplasma retinochoroiditis include laser photocoagulation, submacular surgery, PDT, and anti-VEGF agents [1].
Because of the young age of our patients and occurrence of permanent scotoma or a blind spot in the central visual field with laser photocoagulation, this technique is not suitable for treatment. Surgery can have its own complications and does not prevent recurrences.
Photodynamic therapy appears to be effective. Although, an early recovery of visual acuity has been observed with PDT, multiple treatments have been required [2].
In our small series of patients at 6-to 25-month follow up, leakage diminished in all patients. A reduction of CMT was recorded in all subjects. This change of retinal morphology is likely to be the result of a combined antiexudative effect due to the decrease of vessel permeability and the antiproliferative effect due to the inhibition of further CNV growth following the VEGF blockage [1]. These anatomical improvements were associated with concomitant increases in VA. The mechanism of this outcome remains uncertain.
A previous case reports of CNV due to toxoplasmosis treated with IVB show an improvement of the patient's BCVA [3][4][5]. In our patients, VA increased to normal levels and was preserved until the end of follow-up. Unlike the repeated injections generally needed in patients of CNV secondary to age-related macular degeneration [1] in our study only one injection was required to achieve a good visual outcome.
Our data seem to confirm the efficacy and safety of anti-VEGF therapy in eyes with CNV secondary to ocular toxoplasmosis, although we realize that the present study has some limitations, including the limited number of patients and the absence of a standard protocol for follow-up and treatment.