Atypical ocular toxoplasmosis leading to diagnosis of AIDS: Case Report
Active ocular toxoplasmosis is characterized by a necrotizing retinochoroiditis lesions accompanied by localized or diffuse vitritis. In immunocompetent patients, lesions are usually self-limited and resolve within two months. Atypical forms of ocular toxoplasmosis such as diffuse outer retinitis, which can mimic acute retinal necrosis (ARN), punctuate outer retinal toxoplasmosis, occlusive retinal vasculitis, neuroretinitis, scleritis, and exudative retinal detachment, have been reported.
This parasite can be fatal in immunocompromised individuals, such as HIV/AIDS patients especially those with CD4 T lymphocyte cell counts less than 200 cells/μL. In such a setting, reactivation of opportunistic organisms like Toxoplasma gondii can occur with multiorgan involvement, especially central nervous system (CNS), and with much lower incidence, ocular involvement.
Pour et al reported an atypical presentation of ocular toxoplasmosis with a serous retinal detachment which led to the diagnosis of AIDS. The serous retinal detachment resolved with antitoxoplasmosis treatments and HAART.
A 38-year-old woman was referred to the retina department of Farabi Eye Hospital with metamorphopsia and reduced vision in the right eye over the past 3 weeks. At the time of the presentation, she mentioned anorexia and losing 10 kg in the past three months, and signs of anemia like paleness of face skin, bed nails, and bilateral angular cheilitis were observed.
Uncorrected visual acuity in the right eye was counting fingers at two meters. Posterior synechia (PS) and pigment deposit over the anterior crystalline lens capsule precluded precise refraction in this eye.
Slit-lamp examination revealed granulomatous keratic precipitates (KPs) distributed in Arlt's triangle, 2+ cells in the anterior chamber, and a relatively broad-based PS causing a keyhole appearance in the pupil. The crystalline lens was clear and 2+ cells were present in the anterior vitreous.
Fundus examination was remarkable for a white patch surrounding a scar, inferonasal to the optic disc with three disc diameter size. Some fibrous bands were emanating from the lesion, and the retina around this region was detached with considerable extension towards the superior, nasal, and inferior periphery, while no breaks could be appreciated.
The vision in the left eye was 20/20, and ophthalmic examination was unremarkable in this eye. Spectral-domain optical coherence tomography (SDOCT) (Spectralis Heidelburg Germany) disclosed evidence of vitritis, a detached posterior hyaloid face, and a fine epiretinal membrane (ERM) nasal to the fovea in the right eye.
She denied using any medications or having other illnesses. Considering systemic symptoms and signs and due to involuntary weight loss, the patient underwent a comprehensive infectious, neoplastic, and rheumatologic workup.
Based on the ocular findings, additional tests were ordered for Toxoplasma gondii antibodies which revealed the presence of IgG antibodies while IgMs were absent.
Imaging studies including chest-X-ray, abdominal sonography, and age-related neoplastic workup including mammography, Pap smear, and colonoscopy were unremarkable except for nonspecific polyps in the patient's large intestine.
Enzyme-linked immunosorbent assays (ELISA) for HIV antibodies came back positive which was later confirmed with the Western blot test. Once the diagnosis of toxoplasmic retinochoroiditis in an immunosuppressed patient was established, treatment with trimethoprim/sulfamethoxazole (TMP/SMX) 160/800 mg twice daily was commenced. Brain magnetic resonance imaging (MRI) showed multiple ring-enhancing lesions in both cerebral cortices.
Meanwhile, three weeks after initial ophthalmic presentations, the patient developed a right hemiparesis. Due to the numerous lesions in the patient's motor cortex in the left and right lobes, the diagnosis of toxoplasmic encephalitis was made for the patient. Highly active antiretroviral therapy (HAART) was added to her antitoxoplasmosis treatment four weeks after initial presentation and the dose of trimethoprim/sulfamethoxazole (TMP/SMX) increased to 160/800 mg/three times a day and azithromycin 250 mg/daily was added to the antitoxoplasmic regimen. The systemic steroid was not added to the patient's treatment regimen due to concerns about the patient's immunosuppression.
Two months after initial presentation, vitreous inflammation decreased substantially, subretinal fluid gradually resolved, and the uncorrected visual acuity improved to 20/100. Yellow subretinal hard exudates appeared in the perifoveal area with complete reattachment of the retina in three months. Two months after starting HAART, the patient's hemiparesis improved significantly during this time.
This case shows some ocular and systemic features that are not commonly expected in the typical case of toxoplasmic retinochoroiditis. In this case, pursuing these atypical features led authors to the diagnosis of AIDS.
The first red flag was the presence of an extensive retinal detachment with tractional bands surrounding the central scar and no responsible break which could be suggestive of tractional and/or exudative retinal detachment in this case.
This case represents the exudative detachment with no distinct retinal break. Observation of a retinal fold may advocate the presence of a tractional component in this case. The resolution of RD following an antitoxoplasmic regimen and HAART and without surgical intervention may suggest that decision upon surgery should not be rushed in such patients, and a period of close follow-up visits for ocular examination combined with appropriate systemic treatment may be warranted.
The possibility of toxoplasmic encephalitis should be investigated in every patient with HIV and retinochoroidal toxoplasmosis. The study of choice for this purpose is brain MRI with contrast that can illustrate characteristic enhancing ring lesions.
"This report highlights the fact that sometimes the eyes are the site of the first presentation of a systemic life-threatening condition and emphasizes the role of ophthalmologists in such cases. Judicious ocular and systemic evaluation of patients with ocular toxoplasmosis are of utmost importance. In cases of atypical presentation, appropriate laboratory tests and CNS imaging should be requested. Systemic treatment with antitoxoplasmosis regimens and HAART is mandatory in AIDS patients with ocular toxoplasmosis. Treatment options for retinal detachment in this setting should be meticulously approached."
Source: Pour et al; Hindawi Case Reports in Ophthalmological Medicine Volume 2021,