Joe & Jerry Flew the Coop

The test was a PCR on blood, which was positive for influenza A H1N1.This extent of retinal infarction and LGB infarction has not been previously reported in H1N1 disease or in any other condition. A previous case 1 of non-confluent cotton wool spots in H1N1 may have represented a milder version of ischemic retinopathy. Isolated lateral geniculate body (LGB) infarction has not been described in H1N1 influenza, but bilateral pan-thalamic lesions have been reported.2-4 However, in none of those cases was the LGB infarcted without involving the rest of the thalamus, and in no case was vision loss or retinal infarction described. Why should the retina and LGB have been selectively targeted for infarction? In acute necrotizing encephalopathy (ANE),4 an influenza-related condition in which hemorrhages can be seen in the deep gray matter, the pathogenesis is based on breakdown of the blood-brain barrier through cytokine storm in response to virus exposure,5 akin to a mechanism proposed for Purtscher retinopathy. The patient was treated with oseltamivir, intravenous methylprednisolone, intravenous immunoglobulin (IVIG) and plasmapheresis for presumed influenza-related encephalitis. On examination 60 days after onset, visual acuity had improved to finger counting. The optic discs were pale and the retinal whitening had disappeared. Repeat MRI 75 days from symptom onset showed resolution of FLAIR signal changes and maturation of the LGB hemorrhages.