Early clinical, radiological and EEG improvement following L-arginine infusion in SMART syndrome

Abstract

Objectives: To report the clinical, radiological (MRI) and neurophysiological (EEG) changes in a case of SMART (stroke-like migraine attacks after radiation therapy) syndrome following treatment with intravenous L-arginine. Methods: A 60-year-old woman had, ten years prior, been diagnosed with primary CNS diffuse large B cell lymphoma, and was successfully treated with curative chemotherapy and whole brain radiotherapy. She presented acutely with left-sided headache, teichopsia and dysphasia following a chest infection. MRI of the brain showed striking left parieto-occipital gyral swelling, diffusion restriction, leptomeningeal enhancement, and increased cerebral blood volume. Her EEG showed an excess of slow activity diffusely, particularly over the left temporal lobe. A diagnosis of SMART syndrome was made. Intravenous L-arginine (0.5 g/kg) was administered. Results: A few hours post infusion, her migrainous headache subsided and her mentation improved. Her MRI brain performed six days post infusion showed reduced cortical swelling and hyperperfusion, and her EEG showed less temporal slowing. She continued to improve cognitively. Discussion: This is the first report of SMART syndrome with a response to L-arginine, reflected clinically by a measurable improvement in cognition, brain perfusion and EEG parameters, encouraging further clinical studies.