Outer retinal toxoplasmosis

Multimodal Imaging in Ocular Toxoplasmosis

Multimodal imaging relies on combination of multiple imaging modalities to precisely delineate pathological changes in the posterior segment of the eye associated with a wide range of conditions. This combined application of fundus photography, optical coherence tomography, fundus reflectance/autofluorescence and fundus angiography (with fluorescein, indocyanine green and/or optical coherence tomography) is of great utility for assessment of patients with ocular toxoplasmosis. Multimodal imaging is helpful to characterize the typical pattern of toxoplasmic retinochoroiditis, with primary focal inflammatory involvement of the neurosensory retina, and secondary changes at the level of underlying choroid, retinal blood vessels, vitreous and even optic disc. It may also be valuable to document and follow local complications, including macular edema, vascular occlusions, and choroidal neovascularization, among others.

The Eye as a Window to Systemic Infectious Diseases: Old Enemies, New Imaging

BACKGROUND

Syphilis, tuberculosis and toxoplasmosis are major infectious diseases worldwide; all of them are multisystem pathologies and share a possible ocular involvement. In this context, a fundamental help for the definitive diagnosis is provided by the ophthalmologist, through clinical evaluation and with the aid of a multimodal imaging examination.

METHODS

We hereby describe selected cases who came to our attention and were visited in our eye clinic. In all clinics, the use of retinal and optic disc multimodal imaging during ophthalmological evaluation allowed to make a diagnosis of an infectious disease.

RESULTS

In our tertiary referral center more than 60 patients with syphilis, tuberculosis and toxoplasmosis have been evaluated in the last two years: In 60% of cases the ophthalmological evaluation was secondary to a previous diagnosis of an infectious disease, while in the remaining cases the ophthalmologist, with the help of a multimodal imaging examination and clinical evaluation, represented the physician who leads to the diagnosis.

CONCLUSION

Our results confirm how in these life-threatening pathologies a prompt diagnosis is mandatory and may benefit from a multidisciplinary and multimodal imaging approach, especially during ophthalmological evaluation.

Intravitreal methotrexate in the management of presumed tuberculous serpiginous-like choroiditis

PURPOSE

To report on the use of intravitreal methotrexate (IVT MTX) as part of treatment of presumed tuberculous serpiginous-like choroiditis progressing despite the use of tuberculostatics.

METHODS

Case series of patients suffering from serpiginous-like choroiditis with positive tuberculin skin test who received IVT injections of MTX as part of treatment. Ocular disease was active despite the use of systemic tuberculostatic (isoniazid, rifampicin, pyrazinamide, and ethambutol), and choroidal lesions showed signs of progression. A single injection of IVT MTX (400 μg/0.1 mL) was administered in the eye with macular-threatening features. Change in visual acuity, appearance of the lesion, and staining patterns on angiography were among the main outcome measurements.

RESULTS

Three eyes from two patients were included. Both cases presented bilateral involvement with mild vitritis. In all three eyes, choroidal lesions healed within the first month after an IVT MTX injection with visual acuity improvement in two. No adverse reaction was related to the medication or to the procedure. Patients were followed for a mean of 13.5 months after being injected.

CONCLUSION

The use of IVT MTX seems effective in the management of the inflammatory component of tuberculous serpiginous-like choroiditis, whereas systemic tuberculostatics are aimed at controlling the infectious one.

Pediatric uveitis: An update

Because of their varied spectrum of clinical presentation and difficulty in management, pediatric uveitis remains a challenge to the ophthalmologist. Variations in clinical presentation, difficulties in eye examination, extended burden of the inflammation over quality of life, limited treatment modalities, risk of amblyopia are the main challenges in the management of pediatric uveitis. Pediatric uveitis is a cause of significant ocular morbidity and severe vision loss is found in 25-33% of such cases. This article summarizes the common causes of uveitis in children with special approach to the evaluation and diagnosis of each clinical entity.

Spectral optical coherence tomography findings in patients with ocular toxoplasmosis and active satellite lesions (MINAS Report 1)

PURPOSE

To characterize the active retinochoroiditis lesion observed in patients with the classic clinical presentation of ocular toxoplasmosis (OT) utilizing spectral optical coherence tomography (SOCT).

METHODS

Twenty-four patients with OT and satellite lesions underwent standardized ophthalmologic examination and multimodal fundus imaging. The SOCT findings observed at presentation were described.

RESULTS

The mean age of the fourteen (58.3%) women and ten (41.7%) men was 27.6 years. The mean LogMAR ETDRS best-corrected visual acuity was 0.58 (Snellen equivalent, 20/80(+1) ). On SOCT evaluation, the posterior hyaloid was diffusely thickened in 23 (95.8%) of 24 eyes, increased hyper-reflective signals in the vitreous were observed in 18 (75.0%), and vitreal spherical hyper-reflective depositions were observed in 12 (50.0%) eyes. In all patients, at the active OT lesion site, the inner retinal layers were abnormally hyper-reflective with full-thickness disorganization of the retinal reflective layers (smudge effect); associated choriocapillaris/choroidal optical shadowing was observed in 22 (91.7%) eyes. The retina was thickened in 22 (91.7%) eyes, the retinal pigment epithelium-Bruch membrane reflective complex was focally increased or contained focal splits in 16 (66.7%) eyes and the choroid appeared thickened in 17 (70.8%) eyes. Disorganization of the outer retinal highly reflective layers adjacent to the active OT lesion was observed in all eyes.

CONCLUSION

Full-thickness disorganization of the retinal reflective layers, generally associated with some degree of posterior optical shadowing, was observed in the active OT lesion in all patients. The posterior hyaloid was often thickened and, adjacent to the OT lesion, the outer retina was consistently altered.

Ocular toxoplasmosis II: clinical features, pathology and management

The term, ocular toxoplasmosis, refers to eye disease related to infection with the parasite, Toxoplasma gondii. Recurrent posterior uveitis is the typical form of this disease, characterized by unilateral, necrotizing retinitis with secondary choroiditis, occurring adjacent to a pigmented retinochoroidal scar and associated with retinal vasculitis and vitritis. Multiple atypical presentations are also described, and severe inflammation is observed in immunocompromised patients. Histopathological correlations demonstrate focal coagulative retinal necrosis, and early in the course of the disease, this inflammation is based in the inner retina. For typical ocular toxoplasmosis, a diagnosis is easily made on clinical examination. In atypical cases, ocular fluid testing to detect parasite DNA by polymerase chain reaction or to determine intraocular production of specific antibody may be extremely helpful for establishing aetiology. Given the high seroprevalence of toxoplasmosis in most communities, serological testing for T. gondii antibodies is generally not useful. Despite a lack of published evidence for effectiveness of current therapies, most ophthalmologists elect to treat patients with ocular toxoplasmosis that reduces or threatens to impact vision. Classic therapy consists of oral pyrimethamine and sulfadiazine, plus systemic corticosteroid. Substantial toxicity of this drug combination has spurred interest in alternative antimicrobials, as well as local forms of drug delivery. At this time, however, no therapeutic approach is curative of ocular toxoplasmosis.

Prevalence, clinical characteristics, and causes of vision loss in patients with ocular toxoplasmosis

PURPOSE

To describe the prevalence, demographics, clinical features, and contributors to vision loss at presentation in a large cohort of patients with ocular toxoplasmosis seen at a tertiary referral center in northern California.

METHODS

A retrospective review of the charts of 233 patients with ocular toxoplasmosis examined over 24 years.

RESULTS

Ocular toxoplasmosis was diagnosed in 233 (8.4%) of 2761 patients with uveitis. The mean age at presentation was 27.2 years. Patients with ocular toxoplasmosis were more likely to be young (p<0.01), male (p<0.001), and Latino (p<0.001) as compared with patients in the entire uveitis cohort. At presentation, 159 patients (68.2%) had active disease, which was unilateral in all but one. Among the 160 eyes with active disease, 145 (90.6%) presented with a focal retinochoroiditis, 57.2% of which had an adjacent retinochoroidal scar. Atypical presentations occurred in 11 patients (6.9%). Of eyes with active disease, the main contributors to vision loss at presentation were intraocular inflammation (74.8%) and macular involvement (24.3%), whereas in eyes with inactive lesions the main contributors to vision loss were macular scar formation (67.9%) and amblyopia (11.3%). Younger age was the single significant predictor of macular involvement.

CONCLUSIONS

Ocular toxoplasmosis is a common cause of uveitis. Our patients were more likely than general uveitis patients to be young, male, and Latino, often having emigrated from Mexico or Central or South America. The most common contributors to decreased vision in eyes with active lesions were inflammation and macular involvement, whereas in eyes with inactive lesions they were macular scar formation and amblyopia.

Visual function in human ocular toxoplasmosis

AIM

To assess functional impairment in terms of visual acuity reduction and visual field defects in inactive ocular toxoplasmosis.

METHODS

61 patients with known ocular toxoplasmosis in a quiescent state were included in this prospective, cross-sectional study. A complete ophthalmic examination, retinal photodocumentation and standard automated perimetry (Octopus perimeter, program G2) were performed. Visual acuity was classified on the basis of the World Health Organization definition of visual impairment and blindness: normal (> or =20/25), mild (20/25 to 20/60), moderate (20/60 to 20/400) and severe (<20/400). Visual field damage was correspondingly graded as mild (mean defect <4 dB), moderate (mean defect 4-12 dB) or severe (mean defect >12 dB).

RESULTS

8 (13%) patients presented with bilateral ocular toxoplasmosis. Thus, a total of 69 eyes was evaluated. Visual field damage was encountered in 65 (94%) eyes, whereas only 28 (41%) eyes had reduced visual acuity, showing perimetric findings to be more sensitive in detecting chorioretinal damage (p<0.001). Correlation with the clinical localisation of chorioretinal scars was better for visual field (in 70% of the instances) than for visual acuity (33%). Moderate to severe functional impairment was registered in 65.2% for visual field, and in 27.5% for visual acuity.

CONCLUSION

In its quiescent stage, ocular toxoplasmosis was associated with permanent visual field defects in >94% of the eyes studied. Hence, standard automated perimetry may better reflect the functional damage encountered by ocular toxoplasmosis than visual acuity.

Vitreoretinal morphology in active ocular toxoplasmosis: a prospective study by optical coherence tomography

AIM

To investigate the third generation optical coherence tomography (OCT3) findings in patients with active ocular toxoplasmosis.

METHODS

A prospective observational case series, including 15 patients with active ocular toxoplasmosis in at least one eye evaluated at a single centre. Vitreoretinal morphological features at baseline and changes within a 24-week follow-up interval on OCT3 were evaluated.

RESULTS

The active ocular toxoplasmosis lesion was classified clinically as punctate (n = 6), focal (n = 6) or satellite (n = 3). Retinal layers were hyper-reflective at the active lesion site, and some degree of retinal pigment epithelium-choriocapillaris/choroidal optical shadowing was seen in all patients. In general, the retina was thinned at the active lesion site in eyes with punctate lesions and thickened in eyes with focal and satellite lesions. When detected by OCT3, the posterior hyaloid appeared thickened. While focally detached over punctate lesions, the posterior hyaloid was partially detached, but still attached to the lesion in focal and satellite lesions. Additional findings (not detected on clinical examination) include diffuse macular oedema (n = 6), vitreomacular traction (n = 3) and maculoschisis (n = 1). During follow-up, a decrease in retinal thickness and focal choriocapillaris/choroidal relative hyper-reflectivity were observed at the former lesion site, and posterior vitreous detachment progressed/occurred in all patients.

CONCLUSION

OCT3 enabled identification of morphological features underestimated on clinical examination in patients with ocular toxoplasmosis, which may expand the clinical spectrum of the disease. Further studies are needed to verify the relevance of OCT3 in assisting with the diagnosis and management of ocular toxoplasmosis.

Third-generation optical coherence tomography findings in punctate retinal toxoplasmosis

PURPOSE

To investigate optical coherence tomography (OCT) findings in patients with punctate retinal toxoplasmosis (PRT).

DESIGN

Observational case series.

METHODS

SETTING

Tertiary ophthalmic referral center.

STUDY POPULATION

Four patients with PRT consecutively evaluated between July 2004 and June 2005.

OBSERVATION PROCEDURES

Clinical examination and OCT.

MAIN OUTCOME MEASURES

Morphologic features at baseline and changes within a 24-week follow-up interval.

RESULTS

Retinal layers were abnormally hyperreflective at the active lesion site and associated with some degree of retinal pigment epithelium-choriocapillaris/choroidal optical shadowing in all patients. The posterior hyaloid was thickened and focally detached (over the lesion). Additional findings include tractional maculopathy (n = 2) and diffuse macular edema (n = 1). During follow-up, focal choriocapillaris/choroidal relative hyperreflectivity was observed at the former lesion site, and posterior vitreous detachment progressed in all patients.

CONCLUSIONS

Our findings suggest that OCT may enable identification of subtle morphologic features previously underappreciated in patients with PRT, which may provide new insights about the disease pathophysiologic mechanisms.

Toxoplasmosis

Toxoplasmosis is the most common cause of posterior uveitis in immunocompetent subjects. The infection can be congenital or acquired. Ocular symptoms are variable according to the age of the subject. For instance, young children present with reduced visual acuity, strabismus, nystagmus, and leucocoria, while teenagers and adults complain of decreased vision, floaters, photophobia, pain, and hyperemia. Toxoplasmic retinochoroiditis typically affects the posterior pole, and the lesions can be solitary, multiple or satellite to a pigmented retinal scar. Active lesions present as grey-white focus of retinal necrosis with adjacent choroiditis, vasculitis, hemorrhage and vitreitis. Cicatrization occurs from the periphery towards the center, with variable pigmentary hyperplasia. Anterior uveitis is a common finding, with mutton-fat keratic precipitates, fibrine, cells and flare, iris nodules and posterior synechiae. Atypical presentations include punctate outer retinitis, neuroretinitis, papillitis, pseudo-multiple retinochoroiditis, intraocular inflammation without retinochoroiditis, unilateral pigmentary retinopathy, Fuchs'-like anterior uveitis, scleritis and multifocal or diffuse necrotizing retinitis. The laboratory diagnosis of toxoplasmosis is based on detection of antibodies and T. gondii DNA using polymerase chain reaction (PCR). Toxoplasmosis therapy includes specific medication and corticosteroids. There are several regimens, with different drug combinations. Medications include pirimetamine, sulfadiazine, clindamycin, trimethoprime-sulphamethoxazol, spiramycin, azithromycin, atovaquone, tetracycline and minocycline. The prognosis of ocular toxoplasmosis is usually good in immunocompetent individuals, as long as the central macula is not directly involved.

Atypical presentations of ocular toxoplasmosis

The diagnosis of ocular toxoplasmosis is based most often on the presence of characteristic clinical findings, which include focal retinochoroiditis, an adjacent or nearby retinochoroidal scar, and moderate to severe vitreous inflammation. However, a variety of less common, "atypical" presentations may be unfamiliar to clinicians, delaying both diagnosis and treatment. Patients who are immunocompromised or elderly may, for example, present with large, multiple and/or bilateral lesions. Other unusual manifestations include punctate outer retinal toxoplasmosis, retinal vasculitis, retinal vascular occlusions, rhegmatogenous and serous retinal detachments, a unilateral pigmentary retinopathy mimicking retinitis pigmentosa, neuroretinitis and other forms of optic neuropathy, and scleritis. Although in the past most cases of ocular toxoplasmosis were considered to result from reactivation of a congenital infection, it is now believed that postnatally acquired infection accounts for many cases of this disease. With appropriate use of antiparasitic therapy, the visual prognosis for patients with both typical and atypical forms of ocular toxoplasmosis may be good.

Punctate outer retinal toxoplasmosis in an HIV-positive child

PURPOSE

To discover whether the outer layer of the retina can be the site for toxoplasmosis in AIDS patients.

METHODS

An HIV-positive child, who previously had a normal ocular examination, was reexamined three months later. This examination showed outer retinal lesions compatible with toxoplasmosis and positive IgM and IgG titers specific for that organism, despite the small drop in the CD4 count.

RESULTS

During the first examination, the antibodies for toxoplasmosis were negative. At the three-months follow-up, the anti-toxoplasmosis antibodies were positive and the rest of the workup was negative, suggesting a strong correlation with the patient's fundus pattern.

CONCLUSION

We describe a case of punctate outer retinal toxoplasmosis uveitis, which has been previously associated with immunocompetent hosts. We, however, believe that it can be seen in immunocompromised patients as well.

Toxoplasma gondii and ocular toxoplasmosis: pathogenesis

Images

Acquired ocular toxoplasmosis. A fluorescein angiography study

A 31-year-old man exhibited a bilateral deterioration of vision over the course of 1 week. The right fundus showed the picture of a central vein occlusion, and the left of a disseminated choroiditis. Indirect immunofluorescent testing indicated a titer of 1:2048 for toxoplasmosis. Fluorescein angiography revealed a hitherto unique picture of isolated choroidal occlusions but neither a central vein occlusion nor a disseminated choroiditis. Using only specific antitoxoplasmotic therapy, the patient regained full visual acuity on both sides. The original findings and the results of a 14-year follow-up are presented.

Current practices in the management of ocular toxoplasmosis

To determine current practices in the management of ocular toxoplasmosis, 72 of 85 uveitis specialists (85%) in the American Uveitis Society completed a detailed questionnaire. Questions involved the indications for beginning treatment, choice of antiparasitic/antimicrobial agents, and experience with treatment of ocular toxoplasmosis in special situations including pregnancy, neonatal infections, and immunocompromised patients. Most of the respondents treat patients whose visual acuity had decreased to worse than 20/200, lesions located in the peripapillary, perifoveal, or maculopapillary bundle regions, and lesions associated with severe vitreous inflammation. Most would not treat patients who retained visual acuity of 20/20, lesions located in the far peripheral retina, or lesions associated with only trace to mild vitreous inflammation. Treatment of other combinations of factors remains controversial. Eight different antimicrobial drugs are used in various combinations for lesions threatening the macula or optic nerve head. Systemic corticosteroids are used by 59 of 62 respondents (95%) as part of their initial treatment regimen. The most commonly used regimens are pyrimethamine/sulfadiazine/corticosteroids (20 of 62 [32%]) and pyrimethamine/sulfadiazine/clindamycin/corticosteroids (17 of 62 [27%]). Adjunctive therapies (photocoagulation, cryotherapy, or vitrectomy) have been used by 20 of 60 respondents (33%). Most alter treatment during pregnancy, in newborn patients, and in patients with the acquired immunodeficiency syndrome.