The Many Faces of Contrast-Associated Encephalopathy: A Systematic Review

The increased use of endovascular procedures shows an increase of neurological deficits after intravascular administration of iodine-based contrast media (ICM). Unfortunately, nonuniform terminology is confusing and may explain low awareness of this ICM-associated neurological adverse drug reaction (nADR). Consequently, we conducted this study to summarize identified risk factors, clinical presentations, radiological features, pathophysiological mechanisms, and treatment strategies of ICM-associated nADR. Additionally, we evaluated, if unifying different terminology of nADR seems to be warranted.

A PRISMA-2020 systematic literature search was conducted. We included scientific articles on contrast-induced encephalopathy (CIE), contrast-induced neurotoxicity (CIN), and transient cortical blindness (TCB) following administration of iodine-based contrast media (ICM). A total of 228 records were eligible for inclusion.

The majority of neurological adverse reactions manifests after invasive contrast enhanced procedures and are mostly described as CIE, CIN, and TCB. Patients present with stroke mimickers and TCB. The onset of symptoms varies from shortly after the administration of ICM till up to 24 hours following ICM application. In most of the patients the neurological symptoms are reversible. The available evidence suggests that there seems to be a common underlying pathophysiology, most likely due to dysfunction of the blood brain barrier (BBB). Risk factors include chronic or end stage renal disease, underlying vascular dysfunction, ICM-volume, and the territory of ICM-administration.

There is need for implementation of formal criteria and raising awareness on risk factors and therapeutic management of nADR following ICM-administration. The authors suggest to summarize currently different terminology under one umbrella of contrast-associated encephalopathy (CAE).