Methotrexate Neurotoxicity Mimicking Stroke (P2.296)

Introduction: Stroke mimics present a difficult diagnostic challenge for clinicians because of the time-sensitive nature of acute stroke treatment. Here we report a case of a patient who presented with classic stroke symptoms and was found to have leukocencephalopathy from intravenous and intrathecal methotrexate. Case: A 25 year old male with acute lymphoblastic leukemia (ALL) presented to the emergency department complaining of acute onset slurred speech and left sided weakness. He was promptly evaluated for possible stroke and found to have left facial droop, dysarthria, left hemiparesis and ataxia. Five days prior to presentation, he had received intravenous and intrathecal methotrexate for his ALL. Initial computed tomography (CT), CT perfusion and CT angiogram of the head and neck were unremarkable. Subsequent magnetic resonance imaging (MRI) of the head revealed hyperintense diffusion-weighted imaging (DWI) signal extending from the ventral midbrain to the centrum semiovale bilaterally. There was also matching hypointensity on the apparent diffusion coefficient (ADC) sequence. Overnight, the patient improved dramatically with complete resolution of his symptoms. He was discharged to home the next day with follow-up MRI twenty days later showing complete interval resolution of the DWI and ADC abnormalities. He remained clinically stable and his planned methotrexate treatment was held. Discussion: Methotrexate is a commonly used anti-neoplastic with many side effects including neurotoxicity. Clinical symptoms include encephalopathy, seizure and focal neurological symptoms such as dysarthria, hemiparesis and hemiparesthesia that can mimic strokes. MRI findings most commonly reported are hyperintensity on DWI with matching ADC hypointensity. FLAIR as well as T2 hyperintensity have also been reported. The exact mechanism is not known, however, it is thought to be due to cytotoxic edema. Fortunately, the abnormalities are reversible with most patients making full recovery. Conclusion: It is important for clinicians to recognize methotrexate-induced neurotoxcity as a possible stroke mimic. Disclosure: Dr. Pham has nothing to disclose. Dr. Ermak has nothing to disclose.