Acute retinal necrosis natural history, complications and prognosis

Symptoms of acute retinal necrosis (ARN) develop rapidly upon the onset of pathogenic infection. The natural progression of ARN depends on whether a case is mild or fulminant. Mild cases of ARN presents with white-yellow necrotic lesions that do not coalesce or lead to retinal detachment; the disease is self-limited. Fulminant cases of ARN will lead to progressive necrosis of retinal tissue, causing pigmentation scarring, vitreous debris, and retinal detachment. Without treatment, ARN will usually progress to bilateral acute retinal necrosis (BARN) within weeks to a few months. Complications resulting from acute retinal necrosis occur due to retinal tissue damage and subsequent infection from the causative pathogen. Without treatment, the prognosis for acute retinal necrosis (ARN) varies. Mild ARN is usually self-limited and will resolve itself without treatment; risk of permanent vision loss is very low. Fulminant ARN will usually progress to complications such as progressive outer retinal necrosis, and therefore carries a worse prognosis. With treatment, the prognosis for ARN is good if the appropriate therapy is administered in the early stages and sustained until symptoms resolve.

Symptoms of acute retinal necrosis (ARN) develop rapidly from inflammatory response to the onset of pathogenic infection.^[1]

• Initial signs and symptoms include conjunctivitis, vision loss, photophobia, and eye pain and pressure.

The natural progression of ARN depends on whether the case is mild or fulminant.

• Mild cases of ARN presents with white-yellow necrotic lesions that do not coalesce or lead to retinal detachment; the disease is self-limited.^[2]
• Fulminant cases of ARN will lead to progressive necrosis of retinal tissue, causing pigmentation scarring, vitreous debris, and retinal detachment. Fulminant ARN has a much greater chance of blindness in the affected eye.

Without treatment, ARN will usually progress to bilateral acute retinal necrosis (BARN) within weeks to a few months.^[3]

• There have been exceptions in which the disease spread from the affected to the previously unaffected eye up to 17 years after the initial diagnosis of ARN, due to reactivation of latent viral infection.^[4]

Complications resulting from acute retinal necrosis occur due to retinal tissue damage and subsequent infection from the causative pathogen, including the following:^[1][5]

• Retinal detachment
• Neurological conditions (e.g., encephalitis, meningitis)^[6]
• Optic neuropathy
• Occlusive retinal vasculopathy
• Proliferative vitreoretinopathy^[7]
• Macular pucker^[8]
• Vitreous hemorrhage
• Neovascularization^[9]
• Phthisis bulbi^[9]

Without treatment, the prognosis for acute retinal necrosis (ARN) varies:^[1]

• Mild ARN: Usually self-limited and will resolve itself without treatment; risk of permanent vision loss is very low.
• Fulminant ARN: Will usually progress to complications such as progressive outer retinal necrosis and has a worse prognosis.
  • Retinal detachment will usually occur without treatment, leading to permanent vision loss.
  • Spread of infection through the anterior chamber to the brain has a particularly poor prognosis if encephalitis or meningitis develops.

With treatment, the prognosis for ARN is good if the therapy is administered in the early stages and sustained until symptoms resolve.

• Uncommonly, prognosis can worsen if the patient is immunocompromised and experiences a subsequent infection due to vulnerability from prolonged topical corticosteroid use.

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