Temporary Visual Loss Due to Posterior Reversible Encephalopathy Syndrome in the Case of an End-Stage Renal Disease Patient

Anton syndrome with bilateral occipital infarct: A case report

Anton syndrome results from damage to the visual cortex of the occipital lobes, where the anterior visual pathways remain intact. This damage results in the characteristic triad of cortical blindness, visual anosognosia, and visual confabulation. This case describes an 80-year-old male with a background of renal transplant 7 years prior, admitted to hospital with worsening transplant function, and soon after developed sudden onset cortical blindness. On examination, the patient was found to be in denial of his blindness and showed signs of visual confabulation, both of which pointed toward a diagnosis of Anton syndrome. Radiological investigation with computed tomography (CT) and magnetic resonance imaging (MRI) revealed bilateral ischemic stroke of the occipital lobes, which was later theorized to have occurred due to sirolimus-induced thrombotic microangiopathy (TMA). To the author's knowledge, this is the first case report of sirolimus-induced TMA, bilateral ischemic occipital lobe stroke, and Anton's syndrome, within the same diagnosis. This case highlights that a diagnosis of bilateral occipital stroke with denial of blindness should suggest a diagnosis of Anton syndrome. This report also discusses the importance of differentiating bilateral occipital infarction on CT imaging, from posterior reversible encephalopathy syndrome (PRES), using MRI.

Posterior Reversible Encephalopathy Syndrome

Purpose of Review

This review provides an updated discussion on the clinical presentation, diagnosis and radiographic features, mechanisms, associations and epidemiology, treatment, and prognosis of posterior reversible encephalopathy syndrome (PRES). Headache is common in PRES, though headache associated with PRES was not identified as a separate entity in the 2018 International Classification of Headache Disorders. Here, we review the relevant literature and suggest criteria for consideration of its inclusion.

Recent Findings

COVID-19 has been identified as a potential risk factor for PRES, with a prevalence of 1–4% in patients with SARS-CoV-2 infection undergoing neuroimaging, thus making a discussion of its identification and treatment particularly timely given the ongoing global pandemic at the time of this writing.

Summary

PRES is a neuro-clinical syndrome with specific imaging findings. The clinical manifestations of PRES include headache, seizures, encephalopathy, visual disturbances, and focal neurologic deficits. Associations with PRES include renal failure, preeclampsia and eclampsia, autoimmune conditions, and immunosuppression. PRES is theorized to be a syndrome of disordered autoregulation and endothelial dysfunction resulting in preferential hyperperfusion of the posterior circulation. Treatment typically focuses on treating the underlying cause and removal of the offending agents.