Rasburicase-induced hypoxia: methemoglobinemia in normal g6pd activity

SESSION TITLE: Critical Care Case Report Posters 49 SESSION TYPE: Case Report Posters PRESENTED ON: 10/10/2023 09:40 am - 10:25 am INTRODUCTION: Rasburicase is a urate–oxidase enzyme used for the treatment of tumor lysis syndrome in patients with large tumor burden. When these tumors have significant necrosis/cellular death, nucleic acids are broken down into uric acid which can overwhelm tubular reabsorption capacity causing acute kidney injury. Rasburicase converts uric acid to allantoin which is excreted by the kidneys. Methemoglobinemia can occur as a rare complication of treatment with rasburicase, primarily in patients with glucose-6-phosphare dehydrogenase deficiency. CASE PRESENTATION: 60-year-old male with a PMH of recently diagnosed T-cell lymphoma presented to the hospital with progressive shortness of breath likely due to pleural effusions. He was diagnosed with malignant ascites and pleural effusions. Given his aggressive T-cell lymphoma with high KIA–67, he was started on rasburicase for tumor lysis syndrome. The following day patient developed hypoxia which did not respond to oxygen and eventually was treated with hi flow system with 100% fio2 with little improvement. His methemoglobin level was measured at 10.8. Methylene blue was started however patient became more hypotensive and obtunded in the following 24 hours and suffered from cardiac arrest. Glucose 6 phosphate dehydrogenase levels were checked and returned as normal. DISCUSSION: Methemoglobinemia occurs when there is an oxidizing agent which converts ferrous (Fe2+) hemoglobin to (Fe3+) hemoglobin. This resulted in increased oxygen binding capacity and decreased delivery to peripheral tissue. G6PD reduces glutathione which is a cellular appropriate for oxidized molecules. There are case reports of G6PD deficiency associated with methemoglobinemia with an oxidized agent including rasburicase in the past, however this case demonstrated rasburicase can cause methemoglobinemia with hypoxia without G6PD deficiency. CONCLUSIONS: Hypoxia of unkown cause in a patient who is being treated with rasburicase should be investigated for methemoglobinemia despite normal G6PD levels. Methylene blue and ascorbic acid are treatment options and should be given in a timely manner to avoid further complications. REFERENCE #1: Ahmed M, Sanchez T, Norgbe S, Picking CR, Millner PG. Rasburicase-Induced Methemoglobinemia. Cureus. 2021 Apr 10;13(4):e14406. doi: 10.7759/cureus.14406. PMID: 33987056; PMCID: PMC8110197. REFERENCE #2: Pirrone, Ilaria MD; Farruggia, Piero MD; Cacciatore, Francesca MD; Giambona, Antonino PhD; Guarina, Angela MD; Marcello, Anna Paola PhD; Mosa, Clara MD; Scalzo, Simona MD; D'Angelo, Paolo MD. Rasburicase-induced Methemoglobinemia: A Case Report and Literature Review. Journal of Pediatric Hematology/Oncology 43(6):p e886-e890, August 2021. DISCLOSURES: No relevant relationships by Joseph Bahgat