Methaemoglobinaemia in a G6PD-deficient child treated with rasburicase

Rasburicase-induced hemolytic anemia and methemoglobinemia: a systematic review of current reports

Since the FDA's approval of rasburicase use for treatment of tumor lysis syndrome (TLS), multiple cases of rasburicase-induced methemoglobinemia and hemolytic anemia have been reported among patients with G6PD deficiency. This study aims to provide a systematic review of cases reporting such adverse reactions to rasburicase. A literature review of published cases in PubMed, Embase, Cochrane, and Web of Science was conducted. Descriptive studies reporting cases of rasburicase-induced methemoglobinemia and/or hemolytic anemia in English were analyzed and summarized in this study. Forty-three cases, including a case from our institution, were included in this study. Most cases (60.5%) received rasburicase for TLS treatment. Almost all patients (93.8%) were tested for G6PD after rasburicase administration. The median time to symptom onset was 24 h. The median methemoglobin level was 10%, peaking after a median of 24 h. The median hemoglobin nadir was 6.1 g/dL, and most patients (n = 32) required blood transfusion. Out of 39 cases with reported outcomes, 35 patients (89.7%) recovered, while four patients (three females and one male) died. The median time to recovery was 4.5 days while the median time to death was 8 days. Screening for G6PD deficiency among high-risk patients is important but not practical in acutely severe settings. When prior screening for G6PD deficiency is not feasible, close monitoring for methemoglobinemia and hemolytic anemia is recommended. Exchange transfusion is increasingly reported as a potentially successful therapeutic modality. Ascorbic acid may provide limited benefits. Methylene blue should be avoided as it may exacerbate hemolysis among these patients.

Rasburicase induced methemoglobinemia: A systematic review of descriptive studies

PURPOSE

There is an increased number of reports being published on rasburicase-induced methemoglobinemia recently. We aimed to identify and critically evaluate all the descriptive studies that described the rasburicase-induced methemoglobinemia, its treatment approach, and their outcomes.

METHODOLOGY

PubMed, Scopus and grey literature databases were searched from inception to January 2022 using search terms "rasburicase" and "methemoglobinemia" without any language and date restriction. A bibliographic search was also done to find additional studies. Only descriptive studies on Rasburicase-induced methemoglobinemia were included for our review. Two contributors worked independently on study selection, data abstraction, and quality assessment, and any disagreements were resolved by consensus or discussion with a third reviewer.

RESULT

A total of 24 reports including 27 patients (23 male, 3 female patients, and 1 study did not specify the gender of the patient) aged from 5 to 75 years were included in the review. Immediate withdrawal of the drug and administering methylene blue, ascorbic acid, blood transfusion, and supportive oxygen therapy are the cornerstone in the management of rasburicase-induced methemoglobinemia.

CONCLUSION

Rasburicase administration should be followed by careful monitoring of patients for any severe complication and treat it as early as possible appropriately. In a patient who presents with rasburicase-induced haemolysis or methemoglobinemia, it is often important to expect a diagnosis of G6PD deficiency unless otherwise confirmed and to avoid administering methylene blue, even though the patient is from a low-risk ethnicity for G6PDD.

Cyanosis Due to Methemoglobinemia as the Presenting Sign of Glucose-6-Phosphate Dehydrogenase Deficiency in a Child: Diagnostic and Clinical Implications

A previously healthy 3-year-old boy presented with pallor, jaundice, cyanosis, and a 24-hour history of vomiting and anorexia following fava bean ingestion. Clinical examination and laboratory findings were consistent with severe nonimmune hemolytic anemia with methemoglobinemia. Given the patient's history, a previously unrecognized glucose-6-phosphate dehydrogenase deficiency was suspected and diagnosed. The aim of this article is to delineate the possible coexistence of methemoglobinemia and glucose-6-phosphate dehydrogenase deficiency in children presented with acute hemolysis and discuss its management while reviewing the existing literature.

Rasburicase-induced Methemoglobinemia: A Case Report and Literature Review

Rasburicase is a recombinant urate oxidase enzyme indicated for tumor lysis syndrome, a potential life-threatening oncologic emergency that occurs most commonly during initial chemotherapy for hematological malignancies. As a result of the defects in the physiological antioxidant pathway, erythrocytes of patients with glucose-6-phosphate dehydrogenase deficiency are not protected against the oxidizing stress exerted by hydrogen peroxide generated with the administration of rasburicase. The authors report a 14-year-old patient, diagnosed with T-cell acute lymphoblastic leukemia, who developed methemoglobinemia and hemolytic anemia with low oxygen saturation after starting steroids, hyperhydratation, and rasburicase administration. The complications resolved with supportive therapy only.

Concordance between glucose-6-phosphate dehydrogenase (G6PD) genotype and phenotype and rasburicase use in patients with hematologic malignancies

Phenotypic rather than genotypic tests remain the gold standard for diagnosing glucose-6-phosphate dehydrogenase (G6PD) deficiency. However, with increasing use of genomic arrays and whole exome or genome sequencing, G6PD genetic data are increasingly available. We examined the utility of G6PD genetic data in patients with hematologic malignancies and the association of G6PD genotype and phenotype with rasburicase-induced methemoglobinemia. We analyzed G6PD activity for 990 patients. Genotype data were available from the Affymetrix DMET array (n=379), whole exome sequencing (n=374), and/or the Illumina exome array (n=634) for 645 patients. Medical records of 341 patients with methemoglobin measures were assessed for the administration of rasburicase. We observed 5 non-synonymous SNPs, 4 of which were known to be associated with deficient G6PD activity (WHO Class I-III). Genotyping 367 males resulted in a positive predictive value of 81.8% (47.8–96.8%), and two males with a Class I-III allele having normal activity both received a red blood cell transfusion prior to the activity assay. However, genotyping males had only 39.1% (20.5–61.2%) sensitivity. Two of the 12 heterozygous females had deficient G6PD activity. Rasburicase-induced methemoglobinemia occurred in 6 patients, 5 of whom had at least one Class I-III allele, despite 2 of these having normal G6PD activity. We conclude that although an apparent nondeficient genotype does not necessarily imply a normal phenotype, a deficient genotype result indicates a deficient phenotype in those without transfusions, and may be a useful adjuct to phenotype to prevent adverse drug reactions.

Germline genetic variants with implications for disease risk and therapeutic outcomes

Genetic testing has multiple clinical applications including disease risk assessment, diagnosis, and pharmacogenomics. Pharmacogenomics can be utilized to predict whether a pharmacologic therapy will be effective or to identify patients at risk for treatment-related toxicity. Although genetic tests are typically ordered for a distinct clinical purpose, the genetic variants that are found may have additional implications for either disease or pharmacology. This review will address multiple examples of germline genetic variants that are informative for both disease and pharmacogenomics. The discussed relationships are diverse. Some of the agents are targeted for the disease-causing genetic variant, while others, although not targeted therapies, have implications for the disease they are used to treat. It is also possible that the disease implications of a genetic variant are unrelated to the pharmacogenomic implications. Some of these examples are considered clinically actionable pharmacogenes, with evidence-based, pharmacologic treatment recommendations, while others are still investigative as areas for additional research. It is important that clinicians are aware of both the disease and pharmacogenomic associations of these germline genetic variants to ensure patients are receiving comprehensive personalized care.

Tumor Lysis Syndrome: A Unique Solute Disturbance

Tumor lysis syndrome (TLS) is a life-threatening disorder that is an oncologic emergency. Risk factors for TLS are well-known, but the current literature shows case descriptions of unexpected acute TLS. Solid tumors and untreated hematologic tumors can lyse under various circumstances in children and adults. International guidelines and recommendations, including the early involvement of the critical care team, have been put forward to help clinicians properly manage the syndrome. Advanced practice nurses may be in the position of triaging and initiating treatment of patients with TLS, and need a thorough understanding of the syndrome and its treatment.

Rasburicase-induced methemoglobinemia: case report, literature review, and proposed treatment algorithm

Rasburicase for the treatment of tumor lysis syndrome has been associated with hemolytic anemia and methemoglobinemia, usually in patients with G6PD deficiency. Risks and benefits should be considered prior to use of rasburicase in at‐risk patients. Methylene blue will worsen the hemolytic anemia in G6PD deficiency and should be avoided.