Varicella zoster-associated acute retinal necrosis and central nervous system complications in natalizumab treated MS patients

There is not much awareness of varicella zoster virus (VZV) associated central nervous system (CNS) infections under treatment with natalizumab. Here we describe two natalizumab treated MS patients who developed acute retinal necrosis combined with CNS vasculitis caused by VZV. In natalizumab treated patients, visual symptoms atypical of optic neuritis should be promptly evaluated by an ophthalmologist. Currently, a total of 12 cases of natalizumab-associated VZV CNS or retinal infections are reported in literature. Our two cases and overview of currently available data provide information on prognosis and treatment decisions of this rare but devastating complication.