Methotrexate induced leucoencephalopathy: A stroke mimic
A 16-year-old girl diagnosed to have acute lymphocytic leukaemia (ALL) was admitted for consolidation phase of chemotherapy. Her previous chemotherapy cycles were uneventful. Nine days after the second cycle of consolidation chemotherapy which included IV-Methotrexate (IV-MTX) and Intrathecal-Methotrexate (IT-MTX) she developed sudden onset of parasthesias over left face and left side of body while watching television in her hospital bed. On trying to move her limbs immediately after these symptoms, she noticed clumsiness in using her left upper limb and weakness in her left lower limb. An urgent neurology referral was made for possible stroke. Her power was grade 4/5 in the left upper limb and 4+/5 in the left lower limb. There was no significant ataxia. The deep tendon reflexes were normal and symmetrical in all four limbs. Plantar reflexes were flexors. The abdominal reflexes were present and bilaterally symmetrical. There was approximately 20% reduction in pinprick sensations in left half of face. There was no objective sensory sign in the limbs. Due to sudden onset of the symptoms, a clinical impression of sensory motor neurological deficits due to a cerebrovascular event was made and an urgent MRI brain was requested.\nMRI Brain was done 3.5 hours after onset of symptoms []. On FLAIR images, a 2 cm Χ 1.5 cm minimally hyper-intense oval-shape lesion was noted in the right fronto-parietal subcortical region. The lesion showed restricted diffusion on DWI images. MRA was normal [Figure ,]. The lesion was reported as lacunar infarct. The patient was started on antiplatelet agents. Her neurological deficits subsided when she woke up next morning, about 16 hours after their onset.\nCarotid and transcranial Doppler study, 2DECHO, ECG were normal. Thrombophilia screens, ANA, dsDNA, lupus anticoagulant were negative. Lipid panel and homocysteine levels were normal. EEG was unremarkable. Antiplatelet agents were continued.\nFive days after the above neurologic event, the patient received her third cycle of consolidation chemotherapy also consisting of IV-MTX and IT-MTX. She developed thrombocytopenia secondary to chemotherapy and her antiplatelet agents were stopped. On day 11 of this chemotherapy cycle and 3 days after stopping antiplatelet agents, she had another episode of acute onset of left upper and lower limb numbness and weakness along with numbness over left side of face. She woke up with these symptoms which she described to be exactly similar to the first episode. Clinical examination revealed mild weakness in the left upper and lower limb (grade 4+/5). There was no ataxia. The deep tendon reflexes were normal and symmetrical in all 4 limbs, plantars were flexors bilaterally and there was slight reduction in pin prick sensation over left half of her face.\nRepeat MRI of the brain [] again showed an area of restricted diffusion around the area of the initial lesion. Because of the temporal relation to methotrexate treatment, a clinical diagnosis of methotrexate neurotoxicity was made. This time her neurological deficits resolved within 6 hours. Five days later, MRI of brain was repeated and it showed near complete resolution of the lesions [] [For timeline of events see ].