EyeNet Magazine


 
Morning Rounds
The Red Eye From Rio
By Adam Gess, MD, Jon Wender, MD, J. Michael Jumper, MD,
and Emmett T. Cunningham Jr., MD, PHD, MPH
Edited by Thomas A. Oetting, MD
 
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A tough week had gotten worse for Miguel Ferreira,* who was trying to make ends meet to support his wife and newborn daughter. The 22-year-old Brazilian immigrant had been working long hours at a pizzeria when he began losing vision in one eye. When we saw him, he had experienced pain, redness and decreasing vision in his right eye for five days. His past ocular and medical history were noncontributory. He denied any history of trauma, recent illnesses or high-risk sexual behaviors.
 


On examination, BCVA was 20/400 in the right eye and 20/20 in the left. A right relative afferent pupillary defect was detected, and confrontation visual field testing revealed an inferior defect in the right eye. His IOP was normal bilaterally.

Slit-lamp exam of the right eye was notable for mild ciliary flush, fine keratic precipitates over the inferior corneal endothelium, moderate anterior chamber cell and flare, and scattered anterior vitreous cells. Posterior segment exam of the right eye revealed mild vitritis and marked optic disc edema with associated hemorrhages, vascular sheathing and peripapillary retinal whitening (Fig. 1). Macular edema, several intraretinal hemorrhages and an atrophic retinochoroidal scar just below the inferior temporal arcade were also noted. The exam of the left eye was entirely normal.

In summary, the 22-year-old Brazilian had an acute, unilateral, nongranulomatous panuveitis associated with papillitis, vasculitis, peripapillary retinal whitening and a distant atrophic retinochoroidal scar.

Workup and treatment. Initial workup included serial fluorescein angiography (FA), which revealed early peripapillary hyperfluorescence, late leakage from the optic disc and perivascular staining (Figs. 2–4).

Because Mr. Ferreira is from Brazil (where toxoplasmosis is endemic) and had an atrophic retinochoroidal scar, we initiated empiric treatment with trimethoprim-sulfamethoxazole (Bactrim DS), 160 mg/800 mg twice daily, and prednisone, 0.5 mg/kg once daily, while ordering more diagnostic tests.

A PPD skin test was negative and a chest x-ray was unremarkable, which made tuberculosis or sarcoidosis less likely. RPR and FTA-ABS tests also were negative. Serum lysozyme and ACE levels were within normal limits, and serologic testing for Bartonella henselae and B. quintana were negative. Serum levels of anti–Toxoplasma gondii IgM were within normal limits, but serum levels of anti–T. gondii IgG were elevated to 20 IU/ml.

At the one-week follow-up, visual acuity in his right eye had improved to 20/80, the vitritis and papillitis were improving and a macular star had developed (Fig. 5), confirming our initial clinical suspicion of neuroretinitis. He was treated for a total of six weeks with oral prednisone and three months with Bactrim DS twice daily. Three months after the initial presentation, visual acuity returned to 20/25 in the affected right eye and the papillitis and macular star resolved. At one-year follow-up, segmental atrophy of the optic disc had developed and an inferior hemifield defect was present on Humphrey visual field testing (Figs. 6 and 7).

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What’s Your Diagnosis?

THE RIGHT EYE. We noted mild vitritis and marked optic disc edema (Fig. 1). The initial workup included serial FA (Fig. 2–4).
FOLLOW-UP. At one week (Fig. 5), the right eye shows development of a macular star. At one year (Fig. 6, Fig. 7), we noted segmental atrophy of the superotemporal portion of the optic disc with thinning of the corresponding nerve fiber layer, producing an inferior hemifield defect. The macular star has resolved completely, and a Weiss ring is present.

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Discussion. The most common cause of posterior uveitis in immunocompetent patients is T. gondii. Infection is acquired by ingesting oocysts in contaminated water or food, such as raw or undercooked meat. Cats are the definitive host, but humans and other animals serve as intermediate hosts. While ocular toxoplasmosis occurs worldwide, its prevalence is particularly high in Brazil and France.

Neuroretinitis includes the clinical constellation of vision loss, optic nerve swelling and macular star formation. It can occur in association with a variety of infectious agents—most often B. henselae, but also T. gondii, Treponema pallidum, Mycobacterium tuberculosis, Leptospira interrogans, Borrelia burgdorferi, Rickettsia typhi, herpes simplex virus and mumps virus, among others. Despite thorough evaluation, 25 percent of neuroretinitis cases remain idiopathic.

Patients with toxoplasmic neuroretinitis are typically young, visual acuity at time of presentation is usually poor (less than 20/400), and an afferent pupillary defect is almost always present. Anterior chamber inflammation is common. Retinochoroidal scars, when present, provide presumptive support for the diagnosis.

Treatment generally includes antiparasitic agents with or without the addition of oral corticosteroids. Classic therapy—which consists of pyrimethamine, folinic acid, sulfadiazine and prednisone—remains a popular treatment regimen. Trimethoprim-sulfamethoxazole 160 mg/800 mg, either singly or in combination with pyrimethamine or clindamycin, has been employed with increasing frequency in recent years. Treatment duration typically ranges from six to 12 weeks and may be altered based on response to the medication. Maintenance therapy with trimethoprim-sulfamethoxazole can be considered for immunocompromised patients.1

Visual prognosis is frequently good, with most patients recovering most, if not all, vision following treatment.2 The effect of treatment compared with the natural history of the disease is unknown. One report described a patient with toxoplasmic neuroretinitis in whom visual acuity improved to 20/25 without treatment.2

Neuroretinitis is a rare manifestation of infection with T. gondii but should be suspected in patients from regions where toxoplasmosis is endemic. Although a macular star supports the diagnosis of neuroretinitis, it often is not present until two or three weeks after the onset of symptoms, as in our case.3 While no clinical finding is pathognomonic for toxoplasmic neuroretinitis, supportive signs include the presence of one or more retinochoroidal scars in the affected or fellow eye, moderate to severe intraocular inflammation, and/or inflammatory ocular hypertension. Serologic testing can confirm prior exposure. Treatment typically includes antiparasitic agents and oral corticosteroids.
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* Patient name is fictitious.
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1 Holland, G. N. and K. G. Lewis. Am J Ophthalmol 2002;134:102–114.
2 Fish, R. H. et al. Ophthalmology 1993;100:1177–1182.
3 Wade, N. K. et al. Am J Ophthalmol 2000;130:327–334.
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Drs. Gess, Wender, Jumper and Cunningham serve at the California Pacific Medical Center as a resident, retina fellow, chief of retina service and director of uveitis service, respectively. The latter two are in private practice at the West Coast Retina Medical Group, and Dr. Cunningham also is adjunct clinical professor of ophthalmology at Stanford University

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