335: RARE CO-OCCURRENCE OF FAVISM-INDUCED HEMOLYSIS AND METHEMOGLOBINEMIA SECONDARY TO G6PD DEFICIENCY

Abstract

Introduction: G6PD deficiency testing is performed in all American newborns but this diagnosis is largely unknown in the immigrant population. Consequently, it is under-recognized as many are asymptomatic until an exposure; fava beans are known oxidative stressors causing hemolytic anemia. They can also induce methemoglobinemia in G6PD deficiency due to low levels of NADPH; a co-factor involved in regulation of methemoglobin (MetHb). The diagnosis of favism-induced hemolysis & methemoglobinemia in G6PD deficient individuals is rarely reported. The first line treatment for methemoglobinemia is methylene blue, however in patients with G6PD deficiency methylene blue can potentiate the hemolytic anemia. Therefore, the recognition of these two processes’ occurring simultaneously has clinical and therapeutic significance. Description: 37-year-old male born in Yemen presented to the emergency department with 2 days of fatigue, presyncope and dark urine. He consumed 2 large cans of fava beans in the days preceding presentation. On admission, vitals were notable for SpO2 of 67% on room air with no significant change despite oxygen support. Physical exam showed mild scleral icterus and jaundice. ABG revealed PaO2 452 mmHg, O2 saturation 83% and MetHb 14%. Labs also notable for Hgb 11.8 g/dL, haptoglobin < 30 mg/dL, T.Billi 4.8 mg/dL, LDH 310 U/L and peripheral blood smear with blister cells. EKG, CXR and urinalysis were unremarkable. Favism-induced hemolytic anemia and methemoglobinemia due to G6PD deficiency was suspected therefore ascorbic acid 1000 mg every 6 hours was initiated. Despite treatment, the Hgb down trended to a nadir of 5.7 g/dL requiring 4 U PRBC. T.Billi and LDH peaked at 6.2 mg/dL and > 1800 U/L, respectively. MetHb levels dropped immediately after initiation of ascorbic acid to a nadir < 2%. On day 3 the G6PD screen was positive for deficiency and by day 4 the SpO2 returned to 100% on room air. On day 5, labs had stabilized, ascorbic acid was discontinued, and patient was discharged home with hematology follow up. Discussion: The co-occurrence of favism induced hemolysis and methemoglobinemia in G6PD deficient individuals is scarcely reported in the literature. When correctly diagnosed with subsequent initiation of appropriate treatment patients can have complete recovery.