Abstract: ：Objective To investigate ways of prevention and treatment of multi-organ damage in children with acute lymphocyte leukemia (ALL), which is induced by high-dose methotrexate (HD-MTX). Methods The treatment plan of multi-organ damage in an 11-year-old boy with acute lymphocyte leukemia was summarized, who was treated with HD-MTX (6.6 g, 5 g/m²) in our pediatric department in April 2018. Results On the next day after the first intravenous infusion of MTX, the child manifested various symptoms of adverse reactions, such as vomiting, changes in stool characteristics, fever and decreased urine outputs. The blood concentration of MTX at 42 h was 218 μmol/L. On the 4th day, the levels of phosphokinase and inosine were elevated to 173.2 U/L and 382.7 μmol/L, respectively. It was suspected that the multiple-organ damage was induced by MTX excretion delay. Intravenous injection of calcium folinate was administrated at a dose of 100 mg every 6 h. Meanwhile, such symptomatic treatment as hydration alkalization, hemodialysis, anti-infection, antiemetic medication and liver protection was carried out. Subsequently, the patient completely recovered without further complications. Conclusion HD-MTX can cause delayed excretion and induce multi-organ damage. It is recommended that dynamic monitoring of the level of MTX in blood be implemented and immediate measures be taken, including sufficient hydration and alkalization, to reduce the occurrence of adverse reactions and ensure the safety of patients.

Key words: methotrexate, excretion delay, acute kidney injury, chemotherapy-related vomiting, liver injury