Treatment of Refractory Acute Retinal Necrosis with Intravenous Foscarnet or Cidofovir

Diagnostic and therapeutic challenges in acute retinal necrosis; an update

Acute retinal necrosis (ARN) is a rare but severe ophthalmic pathology defined by panuveitis, retinal necrosis, and high rates of retinal detachment. ARN may lead to poor visual outcomes even if promptly diagnosed and treated. ARN may present with a wide spectrum of clinical findings compatible with panuveitis including anterior uveitis, scleritis, vitritis, necrotizing retinitis, occlusive vasculitis, and optic disc edema. The American Uveitis Society introduced clinical criteria in 1994 for the diagnosis of ARN, while more recent criteria have been proposed by the Standardization of Uveitis Nomenclature (SUN) Working Group and the Japanese ARN Study Group. Multimodal imaging is a valuable tool in evaluating patients with ARN, particularly in unusual cases, while utilizing retinal imaging and applying AI algorithms in these areas of clinical research could be highly beneficial. Over the last few years, significant progress has been made in achieving timely diagnosis and treatment. The precise identification of the viral cause in suspected ARN cases has been greatly enhanced by the advancements in PCR techniques and flow cytometry used for intraocular fluids. systemic (intravenous or oral) antivirals with adjunctive intravitreal antiviral therapy are recommended as first-line therapy to reduce disease severity, the risk of vision loss, and retinal detachment incidence. Although aciclovir was the first existing antiviral agent, at present many clinicians prefer high-dose valaciclovir orally or intravenous aciclovir combined with intravitreal foscarnet. Despite significant progress in diagnosing and treating ARN, further research is needed to improve visual outcomes in this challenging clinical condition.

Acute retinal necrosis: A mini review

Acute retinal necrosis is a rare but potentially devastating disease. Even in the era of modern medicine, retinal detachment is a frequent complication leading to vison loss, as well as phthisis bulbi. Whereas IV acyclovir still remains the standard of care, high doses of valacyclovir with/without additional intravitreal injections of foscarnet have been used. In an attempt to reduce the retinal detachment rate, prophylactic laser treatment and early vitrectomy have been proposed. In this article, we aim to review current diagnostic and treatment modalities.

ACUTE RETINAL NECROSIS: Difference in Outcome by Viral Type and Options for Antiviral Therapy

PURPOSE

To investigate differences in outcomes of acute retinal necrosis with confirmed viral polymerase chain reaction between viral types and highlight different treatment options.

METHODS

The study evaluated 22 eyes in 18 patients of polymerase chain reaction-positive acute retinal necrosis at the University of Pittsburgh Medical Center from 2007 to 2018. Outcome measures included final visual acuity, treatment paradigms, and retinal detachment rate.

RESULTS

Eight eyes were polymerase chain reaction-positive for varicella zoster virus, two eyes for herpes simplex virus Type 1 (HSV-1), and 12 eyes for herpes simplex virus Type 2 (HSV-2). Final Snellen best-corrected visual acuity averaged 20/51 for varicella zoster virus, 20/25 for HSV-1, and 20/814 for HSV-2. Retinal detachment occurred in 2 (25%) of varicella zoster virus eyes and 8 (75%) of HSV-2 eyes. One eye with HSV-1 and three eyes with HSV-2 received cidofovir for treatment of refractory retinitis.

CONCLUSION

Acute retinal necrosis secondary to HSV-2 tended to have persistent active retinitis with a higher rate of retinal detachment despite similar treatment protocols, suggesting that in some cases combination intravenous acyclovir and adjuvant intravitreal foscarnet injections are not sufficient. Despite the risk of renal toxicity, intravenous cidofovir may be a consideration in select patients.

Advances and Perspectives in the Management of Varicella-Zoster Virus Infections

Varicella-zoster virus (VZV), a common and ubiquitous human-restricted pathogen, causes a primary infection (varicella or chickenpox) followed by establishment of latency in sensory ganglia. The virus can reactivate, causing herpes zoster (HZ, shingles) and leading to significant morbidity but rarely mortality, although in immunocompromised hosts, VZV can cause severe disseminated and occasionally fatal disease. We discuss VZV diseases and the decrease in their incidence due to the introduction of live-attenuated vaccines to prevent varicella or HZ. We also focus on acyclovir, valacyclovir, and famciclovir (FDA approved drugs to treat VZV infections), brivudine (used in some European countries) and amenamevir (a helicase-primase inhibitor, approved in Japan) that augur the beginning of a new era of anti-VZV therapy. Valnivudine hydrochloride (FV-100) and valomaciclovir stearate (in advanced stage of development) and several new molecules potentially good as anti-VZV candidates described during the last year are examined. We reflect on the role of antiviral agents in the treatment of VZV-associated diseases, as a large percentage of the at-risk population is not immunized, and on the limitations of currently FDA-approved anti-VZV drugs. Their low efficacy in controlling HZ pain and post-herpetic neuralgia development, and the need of multiple dosing regimens requiring daily dose adaptation for patients with renal failure urges the development of novel anti-VZV drugs.

Advances in the Diagnosis and Management of Acute Retinal Necrosis

Acute retinal necrosis (ARN) is a devastating syndrome characterized by panuveitis, retinal necrosis, and a high rate of retinal detachment that may result in poor visual outcomes if not promptly diagnosed and treated. ARN is most commonly caused by viruses with the herpesvirus family. Etiologies include varicella-zoster virus, herpes simplex virus, and cytomegalovirus, and may be promptly diagnosed by polymerase chain reaction testing of aqueous or vitreous fluid. The true incidence of ARN is not known due to its rarity; as a result, clinical treatment is often guided by retrospective case series, case reports, and expert opinion. Standard of care has evolved over time but currently includes a combination of systemic and intravitreal antiviral in conjunction with topical or oral steroids and surgical therapy as needed. Combination therapy may reduce the rate of severe vision loss and increase the rate of visual acuity gain, although further studies are needed in this area. In particular for patients with mild to moderate disease, combination therapy may reduce the rate of retinal detachment. Adjunctive therapies including oral corticosteroid and prophylactic laser barricade are incompletely studied, but corticosteroid in particular, may reduce inflammation, which also is involved in the severe disease pathogenesis observed in ARN. This review discusses the advances in diagnosis and treatment of ARN, including management with combination antiviral medication and surgical interventions.

Ocular manifestations of herpes simplex virus

PURPOSE OF REVIEW

To review ocular manifestations and complications of herpes simplex virus (HSV) and discuss recent advancements in diagnostic and treatment strategy.

RECENT FINDINGS

In-vivo confocal microscopy has expanded our understanding of corneal nerve degeneration, corneal dendritic cell activity, and changes in biomechanical properties in HSV keratitis. Although currently available only as a research tool, metagenomic deep sequencing has the potential to improve diagnostic accuracy beyond the well established PCR technology, especially in atypical cases. Development of an HSV vaccine has shown some encouraging results in a murine model. New treatment options for neurotrophic cornea offer promise, specifically cenegermin nerve growth factor.

SUMMARY

Ocular herpes simplex infection and its complications continue to cause significant visual burden and decreased quality of life. Familiarity with its clinical features, wider adoption of viral PCR diagnostic technology, and recognition of the need for long-term maintenance medications for recurrent or chronic cases form the basis for effective management. Metagenomic deep sequencing, the development of a herpes vaccine, and cenegermin nerve growth factor offer promise as diagnostic, preventive, and therapeutic options, respectively.