Ocular Toxoplasmosis in a Tertiary Referral Center in Sydney Australia—Clinical Features, Treatment, and Prognosis

Abstract

Purpose: The aim of this study was to provide a retrospective analysis of the presentation, demographics, and treatment regimens for ocular toxoplasmosis at a large tertiary referral uveitis center. Design: Retrospective cohort study. Participants: A total of 48 patients with ocular toxoplasmosis who presented to Sydney Eye Hospital participated in this study. Methods: This is a retrospective review of patient files who presented to Sydney Eye Hospital between 2007 and 2016 with clinical features consistent with ocular toxoplasmosis. Baseline risk factors and treatment details were recorded and analyzed. Main outcome measures were visual acuity and relapse rate compared with other studies in ocular toxoplasmosis. Results: The median age was 35.5 (interquartile range 21–50) with 30 (60%) patients having no previous symptomatic episodes or evidence of chorioretinal scarring. Visual acuity at presentation was 0.51 or 6/19 (SE 0.096) and at follow-up 0.31 or 6/12 (SE 0.094). Nine patients experienced a recurrence during the period of observation with median time to recurrence 2.2 years (SE 0.45) and the relapse rate was 0.09/person-years. Location of lesion was predominantly within the vascular arcades (n = 44) with macular involvement in 9 patients. Most patients received clindamycin therapy (n = 34) with pyrimethamine and sulfadiazine was used for those with macula involvement. Conclusions: Patients with ocular toxoplasmosis had fewer recurrences compared with other published series and had better visual recovery. The majority of patients received clindamycin and oral prednisolone which were well tolerated with pyrimethazine and sulfadiazine reserved for those with macula-involving disease.

Treatment Strategy in Human Ocular Toxoplasmosis: Why Antibiotics Have Failed

“…In line with this, the second study found no effect of ABs (Pyrimethamina and Sulfadiazine (PY/SA)) and corticosteroids on BCVA but on time to healing and recurrences compared to steroids alone [ 46 ]. The third study refers to a non-comparative case series treated with ABs (PY/SA) and corticosteroids and reported in the absence of a comparator a positive effect on BCVA and time to healing [ 47 ], which was confirmed by a British retrospective comparative case series that reported a shorter time to healing and less recurrences after 2 different AB treatments (Pyrimethamine and Spiramycin) compared to nothing or corticosteroids alone [ 48 ], and an Australian study using different antibiotics in combination with corticosteroids [ 53 ]. A French RCT compared systemic (PY/SA) and parabulbar antibiotics (Clindamycin) and found no difference in BCVA and time to healing [ 49 ].…”

“…Treatment outcome parameters ( Table 1 ) and outcomes were reported in 10 larger case series and clinical trials ( Table 2 [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]). Five of the 10 treatment studies referred to European and Northern American cohorts [ 45 , 46 , 47 , 48 , 49 ], two each to Iran [ 50 , 52 ] and Brazil [ 51 , 54 ] and one to Australia [ 53 ]. Two of four recurrence prophylaxis studies in immunocompetent individuals with OT came from Brazil, where the incidence and risk of recurrences are significantly higher, thus allowing us to analyze prophylactic strategies during a reasonable study period of 24 months.…”

“…In the studies reported above, limited evidence further supports a synergistic effect of the combination of systemic and intravitreal [ 47 , 48 , 53 ] ABs and corticosteroids [ 51 ] regarding time to healing, whereas one small study did not support a synergistic effect [ 46 ].…”

“…Whereas most of the reported studies differ as much in the treatment protocol and follow-up as in their aims and primary outcomes, visual outcome and reduction in lesion size do not qualify in assessing the effect of antibiotic treatment and thus are not suitable clinical endpoints [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]. In consequence of this mismatch in outcomes, a report by the American Academy of Ophthalmology found that there is a lack of level I evidence to support the efficacy of routine antibiotic or corticosteroid treatment for acute OT in immunocompetent patients [ 36 ].…”

“…An effect of ABs has been reported when given in combination with corticosteroids. In this case, the time to clearance of a functionally relevant vitreal infiltration and thus of visual recovery is shorter, whereas lesion size regression is more pronounced compared to ABs given alone [ 47 , 48 , 51 , 53 ]. This is not surprising, since both vitreal infiltration and inflammatory tissue destruction are biomarkers of the host immune response, but only to a minor part linked to parasite–host interaction in immunocompetent individuals [ 3 ].…”