Methotrexate-induced transient encephalopathy. The experience of the Research Institute of Pediatric Oncology and Hematology named after Academician of the Russian Academy of Medical Sciences L.A. Durnov at N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of Russia

Introduction. Methotrexate is one of the main chemotherapeutic agents of group antimetabolits, includes in the first line of therapy against osteosarcoma. The drug uses in dose 12 g/m2 according to the protocol EURAMOS-1. The range of methotrexate-induced complications includes renal toxity, hepatotoxicity, myelosuppression, skin and mucosal ulcerations, dyspeptic disorders. One of the formidable, but reversible complications, is methotrexate-induced transient encephalopathy (MIE), the clinical manifestations of which occur in more than 15 % of patients in the treatment of which high doses of methotrexate (HD MTX) are used.Materials and methods. At the Research Institute of Pediatric Oncology and Hematology named after Academician of the Russian Academy of Medical Sciences L.A. Durnov at N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of Russia the period from 2013 to 2023 10 cases of MIE were recorded. All patients received therapy according to the protocol EURAMOS-1. The 4 out of 10 patients had a delay in the rate of elimination of HD MTX after the course of chemotherapy. No one patient had electrolyte disturbances with using HD MTX. The median occurrence of the complication’s emerging was 7 days (from 5 to 10 from the start of therapy) and most often developed after 3 courses of methotrexate 12 g/m2 , which corresponds in total 6 doses of methotrexate. Neurological symptoms: headache, visual impairment, aphasia, convulsions were transient and resolved after an average of 24 hours from the start of the treatment.Results. All 10 patients received obligatory alkalization, massive infusion therapy, neuroprotective drugs, as well as decongestant therapy as a treatment of MIE. Subsequently, therapy with methotrexate was continued for the 9 of 10 patients.Conclusions. The standard recommendations for the treatment of MIE do not currently exist. However, the development of severe neurotoxicity does not exclude the possibility of further using of HD MTX in the treatment program