LAUSR

TOPIC: Critical Care TYPE: Medical Student/Resident Case Reports INTRODUCTION: The World Health Organization officially declared COVID-19 as a pandemic in March 2020. Since then, it has caused more than 1.5 million deaths and has affected more than 68 million people worldwide (1). Methemoglobinemia is a very rare and potentially life-threatening condition. Congenital methemoglobinemia is caused by a deficiency in cytochrome b5 reductase (Cyb5R) while acquired is caused by exposure to an oxidizing agent such as chloroquine or dapsone. We present a case of a critically ill patient with COVID-19 pneumonia who developed methemoglobinemia without an identifiable cause. CASE PRESENTATION: A 64-year-old gentleman with past medical history of hypertension presents to the emergency department (ED) with chief complaints of shortness of breath and myalgias for the past 3 days. In the ED, patient was found to tachycardic at 121 beats/minute, tachypneic at 40 breaths/minute, and febrile at 38.6° Celsius. He was found to have elevated COVID-19 labs which included C-reactive protein, lactate dehydrogenase, ferritin, creatine phosphokinase, d-dimer in addition to elevated BUN 53 mg/dL and creatinine 2.92 mg/dL. His COVID-19 PCR resulted positive and was placed on bilevel positive airway pressure (BPAP) for his respiratory distress and transferred to the medical intensive care unit (MICU) for further monitoring. He was started on broad spectrum antibiotics with vancomycin and cefepime along with dexamethasone and remdesivir. Within 24 hours of admission, patient required mechanical ventilation for worsening hypoxemia. Furthermore, his kidney function continued to decline and required continuous renal replacement therapy. His oxygen requirements improved until hospital day 10;where he developed methemoglobinemia measuring 11.8%. Patient was then given methylene blue 1mg/kg and 1.5 grams of ascorbic acid. Hematology was consulted for emergent exchange transfusion as he developed hemolysis but was deemed too unstable and unlikely to benefit. Patient subsequently went into multisystem organ failure and died on hospital day 12. DISCUSSION: To date, there has only been one reported case of COVID-19 complicated by methemoglobinemia without an identifiable cause (2). Our patient tested negative for glucose-6-phosphate dehydrogenase (G6PD) deficiency and a full medication reconciliation was performed without an identifiable cause. However, there have been 10 cases reported that were either associated with use of an oxidizing agent such as hydroxychloroquine or G6PD deficiency (3–6). Therefore, clinicians should be cognizant of the rising cases of methemoglobinemia and COVID-19. CONCLUSIONS: In the setting of COVID-19 pneumonia requiring mechanical ventilation with refractory hypoxemia, clinicians should be mindful that methemoglobinemia may be a contributing factor. Therefore, in the setting of refractory hypoxemia in COVID-19, measuring methemoglobin levels should be considered. REFERENCE #1: 1) Home - Johns Hopkins Coronavirus Resource Center. Accessed December 6, 2020. https://coronavirus.jhu.edu/2) Lopes DV, Lazar Neto F, Marques LC, Lima RBO, Brandão AAGS. Methemoglobinemia and hemolytic anemia after COVID-19 infection without identifiable eliciting drug: A case-report. IDCases. 2021;23:e01013. doi:10.1016/j.idcr.2020.e01013 REFERENCE #2: 3) Faisal H, Bloom A, Gaber AO. Unexplained Methemoglobinemia in Coronavirus Disease 2019: A Case Report. A&A Pract. 2020;14(9):e01287. doi:10.1213/XAA.00000000000012874) Choo SY. Letters to the Editor in Therapeutic Apheresis and Dialysis Rapidly rising methemoglobinemia in a patient with severe COVID-19 treated successfully with red cell exchange transfusion Running Title: Red Cell Exchange for COVID-19 Methemoglobinemia. doi:10.1111/tap.13598 REFERENCE #3: 5) Naymagon L, Berwick S, Kessler A, Lancman G, Gidwani U, Troy K. The emergence of methemoglobinemia amidst the COVID-19 pandemic. Am J Hematol. 2020;95(8):E196-E197. doi:10.1002/ajh.258686) Palmer K, Dick J, French W, Floro L, Ford M. ethemoglobinemia in patient with g6pd deficiency and sars-cov-2 infection. Emerg Infect Dis. 2020;26(9):2279-2281. doi:10.3201/eid2609.202353 DISCLOSURES: No relevant relationships by Paul Nguyen, source=Web Response No relevant relationships by Jonathan Pickos, source=Web Response No relevant relationships by Aryan Shiari, source=Web Response No relevant relationships by Ayman Soubani, source=Web Response