Bilateral acute acquired toxoplasmic retinochoroiditis after steroid therapy for hantavirus pulmonary syndrome: case report

Trabalho realizado no Departamento de Oftalmologia da Faculdade de Medicina de Catanduva Catanduva (SP)Brazil e Departamento de Oftalmologia da Faculdade de Medicina da Universidade de São Paulo USP Campus Ribeirão Preto (SP) Brazil. 1 Doutorado Filiado à Faculdade de Medicina de Catanduva FAMECA Catanduva (SP) Brasil e à Universidade de São Paulo USP Ribeirão Preto (SP) Brasil. 2 Doutorado USP Ribeirão Preto (SP) Brasil. 3 Livre Docente USP Ribeirão Preto (SP) Brasil.

Rubens Camargo Siqueira 1 Rodrigo Jorge 2 Luiz Tadeu de Moraes Figueiredo 3 Bilateral acute acquired toxoplasmic retinochoroiditis after steroid therapy for hantavirus pulmonary syndrome: case report Description of a case of acute acquired ocular toxoplasmosis following hantavirus pulmonary syndrome. A 41-year-old man presenting hantavirus pulmonary syndrome, confirmed in the laboratory by detection of IgM antibodies to the virus, was submitted to high doses of intravenous corticosteroids for two months. After clinical improvement of hantavirus pulmonary syndrome the patient presented visual loss in both eyes that was secondary to a toxoplasmosis retinitis. The retinitis resolved with anti-toxoplasma therapy. Acquired toxoplasmic retinochoroiditis can occur following steroid therapy for hantavirus pulmonary syndrome.

INTRODUCTION INTRODUCTION INTRODUCTION INTRODUCTION INTRODUCTION
In 1993, a previously unknown group of hantaviruses emerged in the Americas as the cause of acute respiratory disease now termed hantavirus pulmonary syndrome (HPS). Hantavirus causing HPS are associated with wild rodent species of the subfamily Sigmodontinae and are transmitted to man by contact or through aerosols of excreta and secretions of infected rodents (1-2) . For treatment of HPS, it is recommended to hospitalize the patient in an intensive-care unit, and to perform mechanic ventilation for the pulmonary edema and the capillary leaking syndrome in the lungs leading to respiratory failure. The use of high intravenous doses of corticosteroids has been reported as useful treatment for improvement of respiratory failure.
Toxoplasma gondii is a significant cause of infectious retinitis in humans. In 1973, it was stated that systemic symptoms with acute acquired toxoplasmosis caused ocular involvement in 2-3% of the affected patients (3) . Theses authors also concluded that only 2-3% of ocular toxoplasmosis was acquired and the majority of cases arose from reactivation of congenital infection. However, a high incidence of acquired infection followed by ocular toxoplasmosis has been observed in southern Brazil suggesting that it might be a more common route of transmission (3)(4) .
Toxoplasma gondii is a common cause of retinochoroiditis. We report here a patient having bilateral toxoplasmosis retinochoroiditis acquired after use of high doses of corticosteroids for treatment of a hantavirus pulmonary syndrome (HPS).

CASE REPORT
A 41-year-old man presented with bilateral visual loss after a two-month period of steroid therapy for respiratory failure secondary to HPS.
On examination, best-corrected visual acuity was 20/400 in the right eye and 20/200 in the left. His intraocular pressures were normal. A mild cellular reaction in the anterior chamber and vitreous was observed by slit-lamp biomicroscopy bilaterally. Fundoscopy evaluation showed retinitis in the posterior poles of both eyes ( Figure 1A,1B). Fluorescein angiography demonstrated early hypofluorescence in the area of retinitis. Late phases showed staining and leakage around borders of the lesion (active lesion) (Figure 2A, 2B).
Laboratory studies including fluorescent treponemal antibody-antibody screen (FTA-ABS), Lyme disease, complete blood count (CBC), erythrocyte sedimentation rate (ESR), HIV screening, tuberculosis skin testing (purified protein derivative -PPD), chest x-ray and three sets of blood cultures were performed with normal results. However, the patient showed serum positive IgM (>0.600) and elevated IgG (>300 IU/ml) anti-Toxoplasma gondii. The patient was treated with pyrimethamine, folinic acid, and sulfadiazine for 5 weeks. After treatment the lesions were healing ( Figure 3A, 3B) and his vision improved to 20/200 (right eye) and 20/100 (left eye) within 2 months.

DISCUSSION
This is the first report of acquired toxoplasmosis following HPS. Immunossupression by use of high doses of corticosteroids, probably, played a main role in the development of ocular toxoplasmosis in this patient.
The role of cellular immunodeficiency in recurrent toxoplasmic retinochoroiditis: has been demonstrated six Cynomolgus monkeys (Macaca fascicularis) with healed toxoplasmic lesions of the retina were immunosuppressed by total lymphoid irradiation and Toxoplasma specimens were able to proliferate in ocular tissue following the administration of immunosuppressive therapy (5) . A possible relationship between systematic corticosteroid use and reactivation of ocular toxoplasmosis has been discussed (6) . These authors showed that the disease occurred at intervals of 20 days to approximately 1 year after the start of corticosteroid therapy. Lesions were typical in appearance, course, and manner in which they responded to antimicrobial therapy.
Other authors described a 58-year-old woman who developed ocular toxoplasmosis while receiving long-term systemic corticosteroid therapy allowing correlation of early histopathologic lesions with their clinical counterpart recorded in fundus photographs (7) .
The case of a 24-year-old man with acquired ocular toxoplasmosis after immunosuppression of tumoral thymic origin has been reported (19) .
An article described a 48-year-old woman with a previous a liver transplant and a cataract extraction who developed a necrotizing retinochoroiditis in her right eye. As the retinochoroiditis progressed, visual acuity worsened to the point of no light perception, and the eye became blind and painful. An enucleation was performed and histologic examination showed Toxoplasma gondii necrotizing retinochoroiditis (20) .
Hantavirus cardiopulmonary syndrome has been associated with respiratory sequelae related to lung fibrosis. In addition, 2 individuals of 8 we examined 15 and 40 months after HPS, treated in the acute phase with corticosteroids, showed scars of chorioretinitis. One of them had negative serology for toxoplasmosis and the other had IgG antibodies to Toxoplas-ma (21) . However, the present study is the first report detecting an acquired toxoplasmosis following HPS.