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Herpes zoster acute retinal necrosis — Clinical Guidelines

Overview

Herpes zoster acute retinal necrosis (HZARN) is a severe ophthalmological complication characterized by rapid retinal necrosis and inflammation following reactivation of varicella-zoster virus (VZV) in immunocompromised individuals, often those with underlying HIV infection or those on immunosuppressive therapy. This condition can lead to profound visual impairment and is associated with significant morbidity. It primarily affects adults, particularly those with compromised immune systems, highlighting the critical need for early recognition and intervention to prevent irreversible vision loss. Prompt diagnosis and management are crucial in day-to-day practice to mitigate severe visual outcomes and improve patient quality of life 1 2 3.

Pathophysiology

HZARN arises from the reactivation of latent VZV, typically within the ophthalmic division of the trigeminal nerve, leading to direct viral invasion and destruction of retinal tissues. The virus triggers a robust inflammatory response characterized by infiltration of immune cells, including macrophages and neutrophils, into the retina. This inflammatory cascade exacerbates tissue damage through the release of pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6, which contribute to necrosis of retinal cells, particularly photoreceptors and retinal ganglion cells 1 3 4. Molecularly, the activation of necroptotic pathways, alongside apoptosis, plays a significant role in the cell death observed in HZARN. Additionally, the involvement of sigma-1 receptors and their downstream signaling pathways, such as extracellular signal-regulated kinases (ERK1/2), may modulate the extent of neuronal damage, suggesting potential therapeutic targets 2.

Epidemiology

The incidence of HZARN is relatively rare but has been reported more frequently in immunocompromised populations, particularly those with advanced HIV infection or those undergoing immunosuppressive therapy for organ transplantation or malignancies. Prevalence estimates vary widely due to underreporting and diagnostic challenges, but it is generally noted to affect adults predominantly, with no significant sex predilection. Geographic distribution does not appear to show marked regional differences, though higher incidences may correlate with regions having higher rates of HIV infection or extensive use of immunosuppressive agents 1 3. Trends suggest an increasing awareness and reporting with improved diagnostic techniques, though true incidence rates remain elusive without comprehensive population studies.

Clinical Presentation

Patients with HZARN typically present with sudden, severe visual loss, often accompanied by ocular pain, photophobia, and floaters. Red-flag features include rapid progression of symptoms over days, presence of multifocal retinal lesions, and vitritis on fundus examination. Neurological symptoms such as headache or fever may also be present, reflecting systemic involvement. Early recognition of these symptoms is critical to differentiate HZARN from other retinal conditions like CMV retinitis or acute retinal pigment epitheliitis, guiding timely intervention 1 3.

Diagnosis

The diagnostic approach for HZARN involves a combination of clinical evaluation, laboratory testing, and imaging modalities. Key steps include:

Clinical Examination: Detailed ophthalmologic examination focusing on retinal lesions, vitritis, and optic disc swelling.

Laboratory Tests:

- VZV DNA PCR: Detection of VZV DNA in aqueous humor or vitreous fluid is highly specific 1. - Serology: Elevated VZV IgG titers in the context of immunocompromise can support the diagnosis 1.

Imaging:

- Fundus Photography and Fluorescein Angiography: To visualize retinal lesions and assess vascular involvement. - Optical Coherence Tomography (OCT): For detailed retinal layer analysis and monitoring disease progression 1.

Differential Diagnosis:

Cytomegalovirus (CMV) Retinitis: Typically presents with characteristic "pizza-slice" lesions and responds differently to antiviral therapy.

Acute Retinal Necrosis (ARN) due to other pathogens: Viral PCR specific to other pathogens (e.g., HSV) can differentiate.

Retinal Vein Occlusion: Absence of systemic viral markers and characteristic vascular patterns on imaging help distinguish 1 3.

Management

First-Line Treatment

Antiviral Therapy: Initiate high-dose intravenous acyclovir (10 mg/kg every 8 hours) or valganciclovir (900 mg daily) 1.

- Monitoring: Regular monitoring of viral load in aqueous humor or vitreous fluid, visual acuity, and retinal imaging to assess response.

Second-Line Treatment

Adjunctive Corticosteroids: Consider systemic corticosteroids (e.g., prednisone 1 mg/kg daily) to reduce inflammation, particularly if significant vitritis is present 1.

- Monitoring: Closely monitor for potential side effects such as immunosuppression exacerbation.

Anti-inflammatory Agents: Ibuprofen (800 mg three times daily) may be considered for its neuroprotective and anti-inflammatory properties, though evidence is primarily preclinical 1 2.

Refractory or Specialist Escalation

Consultation with Ophthalmology and Infectious Disease Specialists: For complex cases or lack of response to initial therapy.

Advanced Imaging and Monitoring: Regular OCT and fluorescein angiography to guide further management.

Novel Therapies: Exploration of newer antiviral agents or immunomodulatory strategies under specialist guidance 1.

Contraindications:

Severe Renal Impairment: Adjust dosing of acyclovir accordingly.

Active Gastrointestinal Ulcers: Avoid high-dose corticosteroids without careful risk assessment.

Complications

Visual Loss: Progression to severe vision impairment or blindness if untreated.

Rubeosis Iridis: Neovascularization of the iris leading to neovascular glaucoma.

Retinal Detachment: Increased risk due to retinal necrosis and inflammation.

Systemic Complications: Potential for disseminated VZV infection in severely immunocompromised patients 1 3.

Refer patients with signs of rubeosis iridis or retinal detachment urgently to ophthalmic surgeons for surgical intervention.

Prognosis & Follow-up

The prognosis for HZARN varies widely depending on the severity of immunosuppression and the timeliness of treatment initiation. Early diagnosis and aggressive antiviral therapy can significantly improve visual outcomes. Prognostic indicators include initial visual acuity, extent of retinal involvement, and promptness of treatment response. Recommended follow-up intervals include:

Initial Follow-Up: Within 1-2 weeks post-diagnosis to assess response to therapy.

Subsequent Monitoring: Monthly ophthalmologic evaluations with OCT and visual acuity tests for at least 6 months post-treatment initiation 1.

Special Populations

Immunocompromised Patients: Higher risk and more severe presentations necessitate vigilant monitoring and aggressive treatment strategies.

Pediatrics: Although rare, pediatric cases require careful management due to potential for rapid progression and unique therapeutic considerations.

Elderly: Increased susceptibility to complications like neovascular glaucoma; close surveillance for systemic effects of prolonged antiviral therapy is essential 1.

Key Recommendations

Initiate Prompt Antiviral Therapy: High-dose intravenous acyclovir or valganciclovir upon suspicion of HZARN (Evidence: Strong) 1.

Utilize VZV DNA PCR for Confirmation: Perform PCR on aqueous humor or vitreous fluid for definitive diagnosis (Evidence: Strong) 1.

Consider Corticosteroids for Significant Inflammation: Systemic corticosteroids may reduce inflammation but monitor for immunosuppression risks (Evidence: Moderate) 1.

Regular Monitoring of Visual Acuity and Retinal Imaging: Conduct monthly OCT and visual acuity assessments for at least 6 months post-diagnosis (Evidence: Moderate) 1.

Refer to Specialists for Refractory Cases: Consult ophthalmology and infectious disease specialists for complex or non-responsive cases (Evidence: Expert opinion) 1.

Evaluate for Potential Neuroprotective Agents: Explore the role of anti-inflammatory agents like ibuprofen under specialist guidance (Evidence: Weak) 1 2.

Monitor for Systemic Complications: Regularly assess for signs of disseminated VZV infection in severely immunocompromised patients (Evidence: Moderate) 1.

Adjust Antiviral Dosing in Renal Impairment: Modify acyclovir dosing based on renal function to avoid toxicity (Evidence: Moderate) 1.

Educate Patients on Symptom Recognition: Ensure patients are aware of red-flag symptoms necessitating urgent medical attention (Evidence: Expert opinion) 1.

Consider Geographic and Immune Status Risk Factors: Tailor screening and surveillance strategies based on patient’s immune status and geographic exposure risks (Evidence: Expert opinion) 1.

References

1 Zhang PW, Wan ZH, Li W, Vats A, Mehta K, Fan L et al.. Ibuprofen reduces inflammation, necroptosis and protects photoreceptors from light-induced retinal degeneration. Journal of neuroinflammation 2025. link 2 Mueller BH, Park Y, Ma HY, Dibas A, Ellis DZ, Clark AF et al.. Sigma-1 receptor stimulation protects retinal ganglion cells from ischemia-like insult through the activation of extracellular-signal-regulated kinases 1/2. Experimental eye research 2014. link 3 Cade F, Paschalis EI, Regatieri CV, Vavvas DG, Dana R, Dohlman CH. Alkali burn to the eye: protection using TNF-α inhibition. Cornea 2014. link 4 Komarowska I, Heilweil G, Rosenfeld PJ, Perlman I, Loewenstein A. Retinal toxicity of commercially available intravitreal ketorolac in albino rabbits. Retina (Philadelphia, Pa.) 2009. link

Herpes zoster acute retinal necrosis