NCMP-37. Clinical patterns and long-term outcomes in stroke-like migraine attacks after radiation therapy (SMART): a case series

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a rare and underrecognized complication of prior cranial irradiation. It is characterized by recurrent migraine-like headaches temporally associated with neurological deficits, including visual disturbance, aphasia and weakness, and seizure activity. MRI brain classically demonstrates unilateral cortical gyriform or ribbon enhancement with corresponding T2/FLAIR changes in previously irradiated regions without clear diffusion restriction or susceptibility changes. MRI changes are transient and may not be found in every attack. Many patients experience clinical recovery with supportive care, accompanied by corresponding radiographic improvement. Recurrent episodes are common though the true incidence and frequency remain to be elucidated. The role of supportive therapy in preventing recurrences is also unclear. Corticosteroids, aspirin, calcium channel blockers and valproate have been suggested as supportive therapy based on a hypothesis of radiation-induced vascular dysfunction. We present a single-institution case series of 6 patients with long term observation of SMART syndrome, consisting of 4 women and 2 men, who received brain radiation between the ages of 12 and 59 for malignant gliomas (3), germ cell tumor (1), atypical meningioma (1) and choroid plexus carcinoma (1). They presented with abrupt onset of SMART syndrome with a range of 6 to 26 (mean 14.5) years after radiation. Recurrence of SMART syndrome occurred in 4 (66%) of our patients. In these recurrent cases, repeat episode(s) occurred within a range of 8 to 38 (mean, 20.5) months of initial presentation. Average follow-up for these cases thereafter range between 12 to 50 (mean, 26.5) months without further recurrent episodes.