Acute Retinal Necrosis Workup

Updated: Feb 16, 2021
  • Author: Andrew A Dahl, MD, FACS; Chief Editor: C Stephen Foster, MD, FACS, FACR, FAAO, FARVO  more...
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Approach Considerations

Acute retinal necrosis (ARN) is a clinical diagnosis. [10, 11]


Laboratory Studies

Laboratory tests are nondiagnostic and may not be conclusive.

Viral titers for the following may be helpful:

  • Herpes simplex virus 1

  • Herpes simplex virus 2

  • Varicella-zoster virus

For baseline, obtain the following:

  • Complete blood cell count

  • Renal function tests

  • Liver function tests


Imaging Studies

Fluorescein angiography is as follows:

  • Not diagnostic

  • Early decrease in choroidal perfusion

  • May show delayed arterial filling

  • Hypofluorescence in areas of active lesions

Ocular ultrasound is as follows:

  • Can rule out retinal detachment in the presence of media opacity sufficient to obscure retinal examination

  • May show enlarged optic nerve sheath [12]

CT scan may show optic nerve sheath enlargement.

MRI may demonstrate concurrent lesions of the optic tract and the lateral geniculate body, suggesting axonal spread.



Lumbar puncture may show cerebrospinal fluid pleocytosis.



Stage 1 is necrotizing retinitis, with the following substages:

  • Stage 1a - Discrete areas of peripheral retinitis

  • Stage 1b - Confluent areas of peripheral retinitis, papillitis, and macular edema

Stage 2 is vitreous opacification or organization.

Stage 3 is regression of retinal necrosis, with secondary pigmentation of the lesion with condensation of the vitreous base.

Stage 4 is retinal detachment, with the following substages:

  • Stage 4a - Acute tractional retinal tears or detachment with traction or proliferative vitreoretinopathy

  • Stage 4b - Chronic retinal detachment