Ocular Toxoplasmosis: Correlation Between Serologic and Ophthalmologic Findings in Acute and Reactivated Choriorretinitis

Abstract

Abstract: : Introduction: Toxoplasmosis is the main cause of retinochoroiditis in humans. Its agent is Toxoplasma Gondii, an obligate intracelular parasite. Infection is acquired by ingestion of food or water contaminated with oocysts shed by cats, or by eating undercooked meat containing tissue cysts. Most of ocular toxoplasmosis seen in adults represent congenital infection. Purpose: To evaluate the reliability of clinical diagnosis of toxoplasmic choriorretinitis, based on serologic findings. Methods: Retrospective study. 110 patients were evaluated and classified clinically as acute or reactivated choriorretinitis. Serologic evaluation was performed to all of them. Clinical and serologic findings were correlated. Classification criteria was as follows. – Clinical Criteria: Acute Choriorretinitis: First episode presenting a sole inflammatory active lesion, without a chorrioretinal scar. Reactivated Choriorretinitis: Congenital infection or acute lesion in the presence of a choriorretinal scar or background of similar episodes. – Serologic Criteria: Acute: Sabin–Feldman (SF) = or > 1:4000, Complement Fixation (CF) >1:10 and/or IgM (ISAGA) positive. Reactivated: SF = or < 1:1000, CF 0 or < 1:10 and IgM (ISAGA) negative. Results: Acute Choriorretinitis (Clinical Criteria): 32 patients. Average 39 Years Old; 13 male; 19 female. OD: 17; OS 15; Bilateral 1. Median SF 1:16000 (256 – 64000). Average CF: 71.5. Reactivated Choriorretinitis (Clinical Criteria): 78 Patients. Average 23 Years Old, 31 male, 48 Female. OD 29; OI 33; Bilateral 17. Median SF 1:256 (16 – 16000). Average CF: 8.5. 94% of patients clinically diagnosed as acute choriorretinitis had also serologic criteria for acute choriorretinitis. 85% of patients clinically diagnosed as reactivated choriorretinitis had also serologic criteria for reactivated choriorretinitis. 15% had intermediate SF levels, between 1:1000 and 1:4000, and FC up to 1:20. Global coincidence was 87,2%. Conclusions: Clinical evaluation of toxoplasmic choriorretinitis had a high coincidence rate with serologic findings. Nevertheless, serologic tests should be performed to patients presenting toxoplasmic choriorretinitis. This will help to confirm doubtful cases and perform an individual follow up.

Keywords: toxoplasmosis • chorioretinitis • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology