Clinical course of von Szily reaction: Case report and comprehensive review of the literature

The Host-Pathogen Interplay: A Tale of Two Stories within the Cornea and Posterior Segment

Ocular infectious diseases are an important cause of potentially preventable vision loss and blindness. In the following manuscript, we will review ocular immunology and the pathogenesis of herpesviruses and Pseudomonas aeruginosa infections of the cornea and posterior segment. We will highlight areas of future research and what is currently known to promote bench-to-bedside discoveries to improve clinical outcomes of these debilitating ocular diseases.

Type I Interferon Signaling Is Critical During the Innate Immune Response to HSV-1 Retinal Infection

Purpose

Acute retinal necrosis (ARN) is a herpesvirus infection of the retina with blinding complications. In this study, we sought to create a reproducible mouse model of ARN that mimics human disease to better understand innate immunity within the retina during virus infection.

Methods

C57Bl/6J wild type (WT) and type I interferon receptor-deficient (IFNAR-/-) mice were infected with varying amounts of herpes simplex virus type 1 (HSV-1) via subretinal injection. Viral titers, optical coherence tomography (OCT) and fundus photography, the development of encephalitis, and ocular histopathology were scored and compared between groups of WT and IFNAR-/- mice.

Results

The retina of WT mice could be readily infected with HSV-1 via subretinal injection resulting in retinal whitening and full-thickness necrosis as determined by in vivo imaging and histopathology. In IFNAR-/- mice, HSV-1-induced retinal pathology was significantly worse when compared with WT mice, and viral titers were significantly elevated within two days after infection and persisted to day 5 after infection within the retina. These results were also observed in the brain where there were significantly higher viral titers and frequency of encephalitis in IFNAR-/- when compared to WT mice.

Conclusions

Collectively, these findings show that our new mouse model of ARN mimics human disease and can be used to study innate immunity within the retina. We conclude that type I interferons are critical in containing HSV-1 locally within retinal tissues and prohibiting spread into the brain.

The Role of Nervous System and Immune System in Herpes Zoster Ophthalmicus Dissemination and Laterality - Current Views

PURPOSE

Herpes zoster ophthalmicus (HZO) is a sight-threatening condition that is defined as HZ involving the ophthalmic division of the trigeminal nerve. Cases of bilateral HZO in recent literature question the notion of HZO being a strictly unilateral disease. Its pathogenesis is a topic of debate and current literature on VZV dissemination lacks insight into the underlying immunology. This review focuses on novel research in immunology of HZO and aims to formulate hypotheses of spread of lesions through the CNS.

METHODS

A literature search was conducted on Entrez PubMed using the search terms "bilateral" and "herpes zoster ophthalmicus". Articles on ("Immunology" or "immune cells") and "herpes zoster ophthalmicus" were also searched for. Articles published from January 1942 to April 2020 that were in English language were included.

RESULTS

Our findings revealed that hypothesised mechanisms of dissemination causing bilateral ocular disease include transmission from nerves to vessel walls, the synergistic action of the immune and nervous systems through the action of substance P and the von Szily reaction.

CONCLUSIONS

These mechanisms may be investigated using newer models of animal experimentation. It is imperative to define the molecular mechanisms behind VZV transmission to improve methods of identification, treatment, and prevention of HZO.

Optic disc edema with peripapillary serous retinal detachment as the presenting sign of necrotizing herpetic retinitis

Purpose

To describe an atypical case of necrotizing herpetic retinitis (NHR) that presented initially with mild anterior uveitis, optic disc swelling, and peripapillary serous retinal detachment (SRD).

Observations

A 48-year-old Asian Indian man presented with blurred central vision and pain in his left eye. Examination revealed mild anterior chamber inflammation, optic disc swelling, and a peripapillary SRD in the affected eye. Multimodal imaging, including widefield fluorescein angiography, showed optic disc leakage and confirmed the presence of a peripapillary SRD, but was otherwise unremarkable with no evidence of retinitis. The patient was diagnosed with presumed Vogt-Koyanagi-Harada disease and was treated with systemic corticosteroids. While there was objective visual improvement initially, the patient subsequently noted peripheral vision loss and was found to have peripheral necrotizing retinitis and occlusive retinal vasculitis in affected eye. Polymerase chain reaction-based testing of aqueous humor detected varicella zoster virus DNA, confirming the diagnosis of NHR.

Conclusion and importance

Optic disc edema and peripapillary SRD may precede the development of overt retinitis in some patients with NHR.