Smart syndrome with clear improvement after high dose corticosteroid therapy, a case report

In this report we present a fifth nine year-old male patient with a history of surgical resection of a Temporal Anaplastic Astrocytoma (grade III), followed by radiotherapy and chemotherapy in 2004 with complete remission and focal epilepsy diagnosed in 2021. In September of 2022, the patient was referred to our service for the embolization of an arteriovenous dural fistula (dAVF) in the right frontoparietal region, in which 70% of the fistula was successfully occluded with Histoacryl+Lipiodol. A few days after the procedure, the patient started to present with recurrent episodes of dysarthria, mental confusion during few hours interspersed with preserved cognition and speech, associated with episodes of migraine-like headaches and reentrant seizures. At this point, a cranial magnetic resonance image was performed, showing prominent gyral enhancement in the T1 post contrast and gyral hyperintensity with cortical thickening in the occipitotemporal, parietooccipital and frontoparietal regions of the left hemisphere. Considering the association of transient focal neurological deficits, epilepsy, migraine, history of brain radiotherapy and the mentioned image findings, the SMART syndrome was hypothesized. The patient received high dose corticosteroid therapy for 5 days and showed radiologic, electroencephalographic and clinical improvement. The SMART syndrome stands for Stroke-like migraine attacks after radiation therapy, an important differential diagnosis for white matter lesions associated to cortical gadolinium enhancement. It is a rare late-delayed complication of cranial irradiation, in which the patient typically presents with transient focal neurological deficits, seizures and migraine-like headaches. It is thought to be a reversible syndrome, although there are descriptions of patients with persistent deficits. There is no consensus for the treatment approach of this condition, even though there are some reports, such as ours, which revealed a clear improvement after the use of steroid pulse therapy, as seen in this report.