Progressive outer retinal necrosis

Progressive Outer Retinal Necrosis (PORN) is a severe infection of the retina that can lead to blindness. It is a variant of necrotizing herpetic retinopathy, and is typically seen in patients with severely compromised immune systems, such as those with AIDS or those undergoing immunosuppressive therapy.

Etiology

Progressive outer retinal necrosis is caused by the varicella-zoster virus (VZV), the same virus that causes chickenpox and shingles. The virus lies dormant in the nerve cells and can reactivate in individuals with weakened immune systems, leading to PORN.

Clinical Presentation

Patients with progressive outer retinal necrosis typically present with rapidly progressive, painless, bilateral vision loss. Other symptoms may include floaters, photopsia (flashes of light), and peripheral vision loss. On ophthalmic examination, multiple areas of retinal necrosis with clear borders can be seen in the peripheral retina, along with vasculitis and optic nerve pallor.

Diagnosis

Diagnosis of PORN is primarily clinical, based on the characteristic appearance of the retina on examination. Fluorescein angiography and optical coherence tomography may be used to confirm the diagnosis. Polymerase chain reaction (PCR) testing of aqueous humor or vitreous humor can be used to detect VZV DNA and confirm the etiology.

Treatment

Treatment of progressive outer retinal necrosis involves aggressive systemic antiviral therapy to control the VZV infection, along with corticosteroids to reduce inflammation. Despite treatment, the prognosis is often poor, with many patients experiencing severe vision loss or blindness.

See Also

• Retinitis
• Cytomegalovirus retinitis
• Acute retinal necrosis
• Varicella-zoster virus

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