Introduction: G6PD deficiency (G6PDD) is a genetic disorder resulting in low levels of the G6PD enzyme which plays a key role in preventing cellular damage from oxidative stress. We report a case of n..
Introduction: G6PD deficiency (G6PDD) is a genetic disorder resulting in low levels of the G6PD enzyme which plays a key role in preventing cellular damage from oxidative stress. We report a case of newly diagnosed G6PDD manifesting as methemoglobinemia (MetHb) and non-autoimmune hemolytic anemia (NIHA) following Rasburicase administration in an elderly male. Case: A 78-year-old male with a history of untreated chronic lymphocytic leukemia (CLL), congestive heart failure and hypertension presented with altered mental status and acute kidney injury. Initial labs revealed a creatinine of 6.89 mg/dL, potassium of 5.2, phosphate of 6.1, calcium of 9.0, uric acid of 13.9, leukocytosis of 68 × 109/L, and hemoglobin of 8.5 g/dL. CT head was negative. Urinalysis revealed pyuria and large leukocyte esterase. Ultrasound showed enlarged kidneys with no hydronephrosis. Due to concern for infiltrative CLL and spontaneous tumor lysis syndrome (TLS), he was treated with 6mg of Rasburicase and broad spectrum antibiotics for possible infection. The next day, the patient became hypoxic to 87% requiring non-rebreather. Imaging confirmed no evidence of pulmonary embolism, pneumonia or pulmonary edema. ABG showed a PaO2 of 280. Given the discrepancy between pulse oximetry and ABG, there was concern for MetHb secondary to G6PDD. Subsequent testing revealed elevated methemoglobin levels and low G6PD levels. Given his G6PDD, methylene blue was contraindicated. He required high flow nasal cannula and was eventually weaned down to room air. His hemoglobin also began to drop requiring multiple transfusions of PRBCs. Labs were consistent with NIHA. Dialysis was initiated for his AKI and he ultimately was discharged home. Discussion: G6PDD is the most common enzymatic deficiency which may present at birth with jaundice; however, most are asymptomatic. This case is unique given the older age of onset of the patient coupled with the rare instance of spontaneous TLS in a patient with CLL. It also illustrates the challenges with typical management strategies. Administering rasburicase vs initiating dialysis is usually considered promptly along with aggressive hydration and electrolyte repletion. However, Rasburicase administration is contraindicated in people with G6PDD due to its potential to cause MetHb and hemolysis. It is often recommended to test G6PD levels prior to administration, however this is not always feasible. Conventional treatment for MetHb includes methylene blue, likewise, this is contraindicated in patients with G6PDD because of its oxidant properties, resulting in further NIHA. Conclusion: MetHb can present in G6PDD patients along with NIHA. Treatment includes supportive therapy with supplemental oxygen, blood products and avoidance of inciting agent. G6PDD may present later in life.