[Rasburicase therapy may cause hydrogen peroxide shock].

Hyperuricemia contributes to the pathomechanism of diseases such as renal failure, gout, tumor lysis syndrome and metabolic syndrome. Tumor lysis syndrome is a complication of malignancies caused by massive tumor cell lysis due to either spontaneous tumor cell lysis or to different therapies and it may cause hyperuricemia. Recently, for treatment of hyperuricemia the recombinant urate oxidase (rasburicase) therapy has been used. This enzyme converts uric acid with high affinity into soluble allantoin which is eliminated by the kidneys. In this reaction high concentration of hydrogen peroxide is generated. This hydrogen peroxide could cause hemolysis and especially methemoglobin formation, in case of glucose-6-phosphate-dehydrogenase and catalase deficiencies. Therefore it is recommended that these enzymes are determined before therapy. For monitoring of rasburicase therapy the determination of serum uric acid concentration is used. More than 95 per cent of Hungarian clinical laboratories are using the uricate oxidase/peroxidase reactions and hydrogen peroxide measurements in the uric acid assays. These assays may be interfered by ascorbic acid and hydrogen peroxide which is generated by rasburicase either in vivo or in vitro.