Original article
Diagnosis of toxoplasmic retinochoroiditis with atypical clinical features

https://doi.org/10.1016/S0002-9394(02)01500-3Get rights and content

Abstract

PURPOSE: To determine the value of aqueous humor analysis for confirming the diagnosis of ocular toxoplasmosis in patients who present with atypical clinical features and to relate the results of local antibody production and polymerase chain reaction (PCR) with the extent of active retinitis and the immune status of the patient.

DESIGN: Retrospective case series.

METHODS: Sixty-seven consecutive patients with retinitis or retinochoroiditis that was clinically consistent with atypical ocular toxoplasmosis underwent diagnostic anterior chamber paracentesis and serological studies. The aqueous humor was analyzed both by PCR to detect Toxoplasma gondii B1 gene and by the Goldman-Witmer coefficient to determine levels of local anti-T. gondii antibody production.

RESULTS: In nine of the 67 cases, PCR was positive for T. gondii; seven of these were negative for local antibody production. All nine patients had illnesses associated with immunosuppression or advanced old age and all had active retinitis with a mean area of 11.5 disk areas (DA). Twenty-five of the remaining 58 cases were positive for local antibody production. These 25 had a mean area of active retinitis measuring 2.6 DA, and 24 of these patients were immunocompetent. All 34 cases with laboratory evidence of ocular toxoplasmosis diagnosed by either method responded to anti-T. gondii agents. The remaining 33 were negative for T. gondii infection by these two methods; some had laboratory evidence of other infections.

CONCLUSIONS: Although in the present study, the sensitivity and specificity of the aqueous humor PCR and Goldman-Witmer coefficient could not be ascertained in the laboratory diagnosis of toxoplasmic retinochoroiditis, the PCR method appears to confirm the diagnosis in immunocompromised individuals with large atypical foci of retinitis. Conversely, determination of local antibody production may be appropriate for proper diagnosis in immunocompetent individuals presenting with small foci of retinitis.

Section snippets

Design

Retrospective case series.

Methods

Sixty-seven consecutive patients who presented initially with clinical features suggestive of atypical T. gondii retinochoroiditis underwent a diagnostic anterior chamber paracentesis. Clinically, all 67 patients showed retinitis without a retinal or chorioretinal scar and the presence of varying numbers of cells in the vitreous humor. All 67 cases also had one or more of the following features: (1) multiple foci of acute retinitis or retinochoroidal lesions either in the posterior pole or in

Results

The PCR test was positive for T. gondii in nine patients, and seven of these nine were negative for the Goldman-Witmer coefficient (≤ 3.0). These nine cases also had retinal lesions measuring 12.1 ± 6.6 DA (Figure 1). Eight of these nine patients had obvious causes of immunosuppression (Table 1). The ninth patient was an 86-year-old woman with no apparent cause of immunosuppression. All nine patients showed positive serological tests (IgG) for T. gondii infection; two also showed anti-T.

Discussion

The typical clinical presentation of ocular toxoplasmosis includes focal retinitis at the border of a preexisting pigmented retinochoroidal scar. In recent years, however, it appears that such typical manifestations may not be observed in all cases. Patients often present with one large focus or multiple smaller foci of posterior retinitis, peripheral necrotizing retinitis, signs of retinal vasculitis, or a focus of retinitis without adjacent pigmented retinal scars.1 Such atypical

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