Favism in an Elderly Female Associated With Low Pulse Oximetry Saturation And A History of Normal Prior Consumption of Fava Beans

Abstract

Stamatis Karakonstantis, Kalliopi Milaki, Dafni Korela, Sofia Pitsigavdaki, Ifigeneia Kassotaki, Despoina Galani and Charalampos Lydakis

Background: G6PD deficiency is common in Meditteranean countries and can cause favism, i.e. hemolysis after consumption of fava beans. Given the x-linked inheritage of the disease, favism is uncommon in female heterozygotes.

Case report: A 74-year-old female presented to the emergency department due to abdominal pain, jaundice and dark urine. The symptoms began after consumption of fava bean, despite uneventful consumption in the past. The patient was hypoxemic on pulse oximetry at presentation, despite normal saturation in concurrent arterial blood gas (ABG) analysis. Laboratory test revealed a negative-coombs hemolytic anemia. Further testing revealed reduced G6PD activity in the patient’s blood (6.7U/g Hb, normal range 7-16). She was managed with intravenous hydration and transfusions, which resulted in resolution of the hypoxemia. She was discharged after a few days of in hospital stay with instructions to avoid fava beans and medications associated with hemolysis.

Discussion: The occurence of favism in this elderly female, despite normal consumption of fava beans in the past, may be explained by the skewed X-chromosome inactivation with aging, resulting in a higher proportion of circulating red blood cells being G6PD-deficient. The low pulse oximetry saturation with normal ABG saturation may be explained by methemoglobinemia associated with favism.

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