Late-Onset Contrast-Induced Encephalopathy After Stent-Assisted Coiling: A Case Report and Review of the Literature

Introduction: Contrast-induced encephalopathy (CIE) is a rare condition with a broad spectrum of neurological symptoms. With the increasing use of endovascular techniques, the disease is becoming ever more important. To date, recent studies have primarily described patients with early-onset CIE, in which symptoms appear shortly after the intervention. This case report represents one of the few reported cases of late-onset CIE. Case description: A 53-year-old woman with a re-recurrent anterior communicating artery aneurysm with coil impaction and a history of two aneurysmal subarachnoid hemorrhages underwent stent-assisted re-recoiling without incident. Some 31 h after the procedure, she experienced a generalized tonic–clonic seizure. Postprocedural magnetic resonance imaging (MRI) earlier that day had shown slight cortical swelling and mild leptomeningeal effusion in the left frontal lobe, without any other abnormalities. Computerized tomography (CT) imaging afterwards ruled out intracranial hemorrhage. Following an otherwise uneventful clinical course, the patient developed impaired vigilance, right-sided leg weakness, and fine-motor impairment of the hand on the sixth day after the intervention. Subsequent MRI demonstrated patent intracranial arteries and no evidence of ischemia. However, the imaging findings were consistent with CIE, showing characteristic cortical swelling and signal alterations in the sulcal subarachnoid space. In addition, multiple cerebral microbleeds were identified. After the initiation of dexamethasone therapy, the patient exhibited prompt neurological improvement, with full neurological recovery at the three-month follow-up. Conclusions: This case appears to be one of the rare documented occurrences of late-onset CIE, highlighting the importance of postinterventional neurological monitoring. Furthermore, it suggests the potential role for high-dose corticosteroid therapy.