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Small Case Series
October 12, 2009

Clinical and Tomographic Features of Macular Punctate Outer Retinal Toxoplasmosis

Arch Ophthalmol. 2009;127(10):1390-1394. doi:10.1001/archophthalmol.2009.251

Classic active ocular toxoplasmosis affects the full-thickness retina with associated vitreous reaction (“light in the fog” appearance).14The observation and demonstration of deep retinal involvement in toxoplasmosis was first introduced by Gass2in 1968. Once Gass introduced this concept, other variations on nonclassic retinal toxoplasmosis were described.35Later that year, Friedmann and Knox3described new morphologic presentations of ocular toxoplasmosis affecting the retina. Punctate lesions localized in the outer (punctate outer toxoplasmosis) or inner (punctate inner toxoplasmosis) portions of the retina were first described by these authors. It was only in 1985 that Doft and Gass5elucidated the outer variation of punctate toxoplasmosis and introduced the term punctate outer retinal toxoplasmosis(PORT). According to these authors, PORT is a subset of ocular toxoplasmosis that initially and primarily affects the outer retinal layers of the macular area, with only mild vitreous reaction. Typically, recurrent lesions occurred in this variant of ocular toxoplasmosis that affected adjacent areas of the macula, resolving spontaneously or forming fine granular gray-white dots. In their small cases series, symptomatic patients seemed to respond satisfactorily early in the course of the disease to antimicrobials and steroids. In this article, we describe 5 patients who developed punctate retinal lesions in the macular area in association with toxoplasmosis. In all 5 patients, diagnosis of ocular toxoplasmosis was supported by elevated serum levels of immunoglobulin to toxoplasma (IgG and IgM) and a favorable response to therapy. Ocular clinical and tomographic findings in these cases provided new insights into the pathophysiology of ocular toxoplasmosis.

Report of Cases
Case 1

A 17-year-old healthy girl was seen initially with blurred vision in the left eye (visual acuity [VA], 20/25). The right eye's VA was normal (20/20). Results of biomicroscopy showed a mild vitreous reaction associated with an active punctate retinitis in the macula of the left eye. An optical coherence tomographic (OCT) line scan through the active lesion showed thickening and elevation of the retinal pigment epithelium (RPE) associated with minimal subretinal fluid in the macular area. Clinical suspicion of toxoplasmosis was confirmed by elevated serum levels of IgG (438 IU/mL; reference value, <2 IU/mL) and IgM (2.7 IU/mL; reference value, <0.5 IU/mL) to toxoplasma. Two weeks after treatment with an oral combination of trimethoprim (160 mg) and sulfamethoxazole (800 mg) (Bactrim F; Roche Pharmaceuticals, São Paulo, Brazil), 2 tablets per day for up to 4 weeks, and prednisone (20-40 mg/d) added 24 hours later, the lesion regressed and VA improved (20/20) (Figure 1).

Figure 1.
Case 1. A, Fundus photography shows active punctate retinitis (arrow) caused by toxoplasmosis (visual acuity, 20/25). B, An optical coherence tomographic line scan through the lesion showed thickening and elevation of the retinal pigment epithelium associated with minimal subretinal fluid in the macular area. C and D, Two weeks after treatment, the lesion regressed (arrows) and visual acuity improved (20/20).

Case 1. A, Fundus photography shows active punctate retinitis (arrow) caused by toxoplasmosis (visual acuity, 20/25). B, An optical coherence tomographic line scan through the lesion showed thickening and elevation of the retinal pigment epithelium associated with minimal subretinal fluid in the macular area. C and D, Two weeks after treatment, the lesion regressed (arrows) and visual acuity improved (20/20).

Case 2

A 11-year-old boy was seen initially with central blurred vision in the left eye (VA, 20/30). The right eye had normal VA (20/20). Results of biomicroscopy showed a mild vitreous reaction associated with active punctate retinitis in the macula of that eye. An OCT line scan through the active lesion showed attachment of the RPE-choriocapillaris layer and the neurosensory retina over the lesion with inflammatory retinal infiltrate in the deeper retinal layers and minimal intraretinal fluid in the macular area. Clinical suspicion of toxoplasmosis was confirmed by elevated serum levels of IgG (626 IU/mL; reference value, <2 IU/mL) and IgM (1.7 IU/mL; reference value, <0.5 IU/mL) to toxoplasma. Two weeks after treatment with an oral combination of trimethoprim (160 mg) and sulfamethoxazole (800 mg) (Bactrim F), 2 tablets per day for up to 4 weeks, and prednisone (20-40 mg/d) added 24 hours later, the lesion regressed and VA improved (20/20) (Figure 2).

Figure 2.
Case 2. A, Fundus photography shows active punctate retinitis (arrow) caused by toxoplasmosis (visual acuity, 20/30). B, Optical coherence tomography (OCT) shows attachment of the retinal pigment epithelium (RPE)–choriocapillaris layer and the neurosensory retina over the lesion with inflammatory retinal infiltrate in the deeper retinal layers (red) and minimal intraretinal fluid in the macular area. C, Two weeks after treatment, the lesion regressed (arrow) and the area of visual disturbance decreased (visual acuity, 20/20). D, An OCT scan showed resolution of the lesion (enhanced image). E, Note the persistence of an old deep punctate lesion (enhanced image) temporally to the fovea underneath the RPE (C, arrowhead).

Case 2. A, Fundus photography shows active punctate retinitis (arrow) caused by toxoplasmosis (visual acuity, 20/30). B, Optical coherence tomography (OCT) shows attachment of the retinal pigment epithelium (RPE)–choriocapillaris layer and the neurosensory retina over the lesion with inflammatory retinal infiltrate in the deeper retinal layers (red) and minimal intraretinal fluid in the macular area. C, Two weeks after treatment, the lesion regressed (arrow) and the area of visual disturbance decreased (visual acuity, 20/20). D, An OCT scan showed resolution of the lesion (enhanced image). E, Note the persistence of an old deep punctate lesion (enhanced image) temporally to the fovea underneath the RPE (C, arrowhead).

Case 3

A 10-year-old boy presented with blurred central vision in the right eye (VA, 20/50). The left eye had normal VA (20/20). Results of biomicroscopy showed a mild vitreous reaction associated with active recurrent punctate retinal lesions caused by presumed toxoplasmosis in the macula of that eye. Optical coherence tomography showed different patterns of retinal involvement of the lesions. Such patterns consisted of small punctate lesions showing attachment of the RPE-choriocapillaris layer and the neurosensory retina and a large punctate lesion with evidence of inner retinal involvement. Clinical suspicion of toxoplasmosis was confirmed by elevated serum levels of IgG (513 IU/mL; reference value, <2 IU/mL) and IgM (2.7 IU/ml; reference value, <0.5 IU/mL) to toxoplasma. Two weeks after treatment with an oral combination of trimethoprim (160 mg) and sulfamethoxazole (800 mg) (Bactrim F), 2 tablets a day for up to 4 weeks, and prednisone (20-40 mg/d) added 24 hours later, the lesions regressed and VA improved (20/30). Six months after presentation, the lesions have resolved. Resolution of the previous active large lesion under the RPE was noted with OCT (VA, 20/20) (Figure 3).

Figure 3.
Case 3. A, Fundus photograph shows active recurrent punctate retinal lesions caused by toxoplasmosis (visual acuity, 20/50). An optical coherence tomography (OCT)–3 scan showed small punctate lesions (B) showing attachment of the retinal pigment epithelium (RPE)–choriocapillaris layer and the neurosensory retina and a large punctate lesion (C), evidence of inner retinal involvement. D, Two weeks after treatment, the lesions regressed and visual acuity improved (20/30). E, Six months after first presentation (visual acuity, 20/20), the lesions had resolved. Resolution of the previous active large lesion under the RPE was noted with OCT.

Case 3. A, Fundus photograph shows active recurrent punctate retinal lesions caused by toxoplasmosis (visual acuity, 20/50). An optical coherence tomography (OCT)–3 scan showed small punctate lesions (B) showing attachment of the retinal pigment epithelium (RPE)–choriocapillaris layer and the neurosensory retina and a large punctate lesion (C), evidence of inner retinal involvement. D, Two weeks after treatment, the lesions regressed and visual acuity improved (20/30). E, Six months after first presentation (visual acuity, 20/20), the lesions had resolved. Resolution of the previous active large lesion under the RPE was noted with OCT.

Case 4

Recurrent vitreitis associated with active multifocal deep gray-white lesions caused by presumed toxoplasmosis was observed in a 10-year-old boy with blurred central vision in the right eye (VA, 20/400). The left eye had normal VA (20/20). Results of OCT through 1 active lesion showed thickening and elevation of the RPE. A partial posterior vitreous detachment with a thickened hyaloid was also observed in that eye. The clinical suspicion of toxoplasmosis was confirmed by elevated serum levels of IgG (827 IU/mL; reference value, <2 IU/mL) and IgM (1.9 IU/mL; reference value, <0.5 IU/mL) to toxoplasma. Four weeks after treatment with oral combination of trimethoprim (160 mg) and sulfamethoxazole (800 mg) (Bactrim F), 2 tablets a day for up to 4 weeks, and prednisone (20-40 mg/d) added 24 hours later, vitreitis and active lesions regressed and VA improved in the right eye (20/100) (Figure 4).

Figure 4.
Case 4. A, Fundus photograph shows recurrent vitreitis associated with active multifocal deep gray-white lesions (arrows) caused by toxoplasmosis (visual acuity, 20/400). B, An optical coherence tomographic line scan through 1 active lesion shows thickening and elevation of the retinal pigment epithelium. A partial posterior vitreous detachment with a thickened hyaloid was observed in this case (arrow). C, Four weeks after treatment, vitreitis and active lesions regressed and visual acuity improved (20/100).

Case 4. A, Fundus photograph shows recurrent vitreitis associated with active multifocal deep gray-white lesions (arrows) caused by toxoplasmosis (visual acuity, 20/400). B, An optical coherence tomographic line scan through 1 active lesion shows thickening and elevation of the retinal pigment epithelium. A partial posterior vitreous detachment with a thickened hyaloid was observed in this case (arrow). C, Four weeks after treatment, vitreitis and active lesions regressed and visual acuity improved (20/100).

Case 5

A 14-year-old boy was seen initially in January 2000 with multifocal subacute recrudescent retinitis caused by presumed toxoplasmosis in the left eye. His right eye had normal VA. Elevated serum levels of IgG (1769 IU/mL; reference value, <2 IU/mL) and IgM (1.7 IU/mL; reference value, <0.5 IU/mL) to toxoplasma confirmed the diagnosis of toxoplasmosis. Two weeks after treatment with oral combination of trimethoprim (160 mg) and sulfamethoxazole (800 mg) (Bactrim F), 2 tablets a day for up to 4 weeks, and prednisone (20-40 mg/d) added 24 hours later, resolution of the previous active lesions with formation of newly punctate lesions associated with mild vitreitis was noted in the left eye. Four months after initial presentation, a new site of retinitis was present in the parafoveal region of the eye. The patient returned only in the year 2005, presenting again with multiple recurring deep punctate lesions in the left macula. An OCT scan through the fovea showed a focal hyperreflectivity limited to beneath the RPE. A few months later, during that year, an area of classic toxoplasmic retinitis associated with a shallow posterior vitreous detachment was observed in the same eye. An OCT3 scan showed increased reflectivity in the inner retinal layers corresponding to the focal retinitis. Decreased reflectivity was observed in the RPE and photoreceptor layer secondary to the shadowing effect (Figure 5).

Figure 5.
Case 5. A, Fundus photograph shows multifocal subacute recrudescent retinitis was caused by toxoplasmosis in January 2000. B, Two weeks after treatment, resolution of the previous active lesions with formation of newly punctate lesions associated with mild vitreitis were noted. C, Four months after initial presentation, a new site of retinitis was present in the parafoveal region (arrow). D, Late-stage presentation of multiple recurring deep punctate lesions in the macula are seen. An optical coherence tomographic (OCT) scan (E) through the fovea showed a focal hyperreflectivity limited to beneath the RPE. Five years after first presentation, an area of classic toxoplasmic retinitis associated with a shallow posterior vitreous detachment was observed (F, arrows). G, An OCT scan showed an increased reflectivity in the inner retinal layers corresponding to the focal retinitis.

Case 5. A, Fundus photograph shows multifocal subacute recrudescent retinitis was caused by toxoplasmosis in January 2000. B, Two weeks after treatment, resolution of the previous active lesions with formation of newly punctate lesions associated with mild vitreitis were noted. C, Four months after initial presentation, a new site of retinitis was present in the parafoveal region (arrow). D, Late-stage presentation of multiple recurring deep punctate lesions in the macula are seen. An optical coherence tomographic (OCT) scan (E) through the fovea showed a focal hyperreflectivity limited to beneath the RPE. Five years after first presentation, an area of classic toxoplasmic retinitis associated with a shallow posterior vitreous detachment was observed (F, arrows). G, An OCT scan showed an increased reflectivity in the inner retinal layers corresponding to the focal retinitis.

Comment

Ocular toxoplasmosis is a leading cause of posterior uveitis in humans. The typical ocular toxoplasmosis lesions are accompanied by an overlying vitritis, leading to the assumption that the inner retinal layers or full-thickness retina are involved in this disease.4This article describes the clinical and tomographic findings of 5 patients with characteristic features of macular punctate outer retinal toxoplasmosis, a subset of ocular toxoplasmosis characterized by the presence of multifocal, punctate outer retinal lesions associated with little vitreous reaction.25In all 5 patients, the diagnosis of toxoplasmosis was supported by elevated serum levels of immunoglobulin to toxoplasma (IgG and IgM) and a favorable response to therapy. Our findings suggest that OCT3 provides new insights into the pathophysiology of this subset of acquired ocular toxoplasmosis presentation. We wonder if the lesions we found were the anatomic representations of granuloma-like lesions (chorioretinitis) as a first line of immunologic defense against choroidal circulating infecting toxoplasmic organisms (acquired infection).1This was suggested in our cases 1 and 2 with OCT. The resultant deep punctate lesions may exudate into the retina and regress slowly or encyst in the subretinal pigment epithelial space. Following this proposed mechanism of disease, we believe that failure to control the infection can give the parasites access to inner portions of the retina1(as seen in cases 3 and 4), causing temporary focal white inflammatory lesions (punctate inner retinal toxoplasmosis) or the more familiar and classic manifestation of toxoplasmic retinitis4with adjacent vitreous involvement (case 5).

In 1985, Doft and Gass,5without the advantage of OCT, believed that the punctate changes in macular PORT represented focal outer retinal gliotic scars or encysted tissue forms of Toxoplasma gondii. Unless histopathology is obtained from these eyes in the active stages of the disease, OCT will be of great clinical use in investigation of the pathogenesis of macular PORT. Our experience with consecutive Brazilian cases with macular PORT indicates that they typically present with acute unifocal or multifocal gray-white lesions, largely confined to the macular outer retinal layers, with mild vitreous reaction. Such lesions resolve slowly, but frequently recur in adjacent areas of the macula. Macular PORT is commonly underreported6and underdiagnosed as an inflammatory macular disease. The white dots that characterize macular PORT must be differentiated from similar deep gray-white changes that may occur in children and young patients with Toxocarainfection, punctate inner choroiditis, multifocal choroiditis, multiple evanescent white dot syndrome, diffuse unilateral subacute neuroretinitis,5,6and acute retinal pigment epitheliitis.7Unlike patients with these inflammatory diseases, those with macular PORT present serologic evidence of exposure to T gondiiand recurring focal white active lesions that may resolve or cause focal chorioretinal scars in the macula with little vitreous reaction. Recognition of the different presentations of toxoplasmosis is important because there is evidence that treatment of macular PORT may be effective.3,5

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Article Information

Correspondence: Dr de Souza, Ophthalmology, Universidade Federal de São Paulo, Rua Mato Grosso, 306 4th 411, São Paulo, 01239-040 Brazil (ecsoftal@uol.com.br).

Financial Disclosure: None reported.

Previous Presentation: This study was presented as a scientific poster at the Annual Meeting of the Retina Society; September 27-30, 2007; Boston, Massachusetts.

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