Secondary dengue retinitis with associated occlusive retinal vasculitis
Dengue is endemic in tropical countries. Secondary dengue infections are generally more dangerous as they lead to an exaggerated response in the patient due to the severe immunological response caused by antibody-dependent enhancement (ADE) leading to severe ocular manifestations like retinitis.
A 42-year-old female was diagnosed as secondary dengue retinitis with associated retinal vasculitis based on her past history, clinical presentation, IgG/IgM ratio, and enzyme-linked immunosorbent assay (ELISA) test for dengue and was successfully treated with oral corticosteroids.
Secondary dengue infection may manifest as retinitis with signs of microvascular occlusions in the retina. A high level of suspicion and IgG/IgM ratio may help in confirming the diagnosis.
KeywordsSecondary dengue retinitis Occlusive vasculitis Post-fever retinitis
Best-corrected visual acuity
Dengue hemorrhagic fever
Dengue shock syndrome
Enzyme-linked immunosorbent assay
Fundus fluorescein angiography
Non-structural protein 1
Optical coherence tomography
Retinal pigment epithelium
Dengue virus belongs to the Flaviviridae family. Secondary dengue infections occur when the patient is affected by a serotype other than the one which caused the primary dengue infection. These infections are generally more dangerous as they lead to an exaggerated immunological response due to antibody-dependent enhancement . The various manifestations of secondary dengue are hemorrhagic fever or dengue shock syndrome and ocular manifestations like sub-conjunctival hemorrhages, retinitis, arteritis with exudation, and vascular sheathing over posterior pole [2, 3]. We report a case of retinitis with associated occlusive retinal vasculitis due to secondary dengue infection which was successfully treated with systemic corticosteroids.
Dengue virus is a member of the Flaviviridae family, genus Flavivirus. Four distinct serotypes (DEN-1, DEN-2, DEN-3, and DEN-4) of dengue virus have been identified. Infection with any of these viruses may be asymptomatic or cause a self-limiting febrile illness known as dengue fever. Although rare, dengue retinitis has been reported after acute dengue fever . Typically, it presents 2–3 weeks after an attack of acute dengue fever. Other reported complications associated with dengue are retinochoroiditis , choroiditis , optic neuritis , central retinal artery occlusion , and panophthalmitis .
Infection with one serotype of dengue virus imparts a lifelong immunity against that particular serotype. Infection with other serotype or multiple infections with different serotypes of dengue virus in a person who was infected with another serotype in the past is called secondary dengue .
Pathogenesis in dengue is linked to the host immune response, which is triggered by infection with the virus. Primary infection is usually benign. Severe infection can be caused by secondary infection with a different serotype or multiple infections with different serotypes. The IgG capture ELISA could be used to distinguish between primary and secondary infection, with 100% of primary infections and 96% of secondary infections being correctly classified. Primary and secondary dengue infections may be classified by determining the ratio of units of dengue IgM to IgG antibody . IgG/IgM ratio of > 1.10 is useful diagnosing secondary dengue .
Our patient had no manifestation of active dengue fever but had a past history of seropositive dengue fever 7 years back. This would have apparently imparted lifelong immunity in her for the serotype of dengue virus which infected her 7 years back. However, the history of two of her family members suffering from dengue fever raised the suspicion of secondary dengue infection in her. On investigations, her IgG/IgM ratio was 1.8 which confirmed the diagnosis of secondary dengue in her.
Numerous reports have identified a second heterologous dengue virus (DENV) infection as a principal risk factor for severe dengue disease (dengue hemorrhagic fever/dengue shock syndrome, DHF/DSS). Dengue cross-reactive antibodies raised following a first dengue infection combined with a second infecting virus to form infectious immune complexes that enter Fc-receptor-bearing cells . This results in an increased number of infected cells and high level of cytokines leading to severe complications.
To the best of our knowledge, this is the first case of secondary dengue retinitis reported.
We report this rare case to highlight the fact that absence of fever in a patient may be misleading to the treating doctor and the patient may be suffering from secondary dengue infection which may manifest as retinitis with signs of microvascular occlusions in the retina. A high level of suspicion and IgG/IgM ratio may help in confirming the diagnosis. Early diagnosis and management may help in complete recovery of vision in such eyes.
We have received no funding for this work from any organization.
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VK provided ophthalmic care to the patient and drafted the manuscript. NC reviewed the literature and drafted the manuscript. MA drafted the manuscript. PK drafted the manuscript. All authors read and approved the final manuscript.
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Consent to publish the case report has been taken from the patient concerned and does not disclose the identity or infringe the privacy of the patient.
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