Blood smear, a key diagnostic tool in hematology: Lessons from two cases of acute hemolysis in previously undiagnosed g6pd deficiency

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common worldwide distributed hereditary red cells enzymatic defect. The most common life-threatening clinical presentation of G6PD deficiency is acute hemolytic crisis triggered by exposition to oxidative agents such as fava beans, drugs, or infections. Management of acute hemolytic crisis in patients with no previous history of hereditary red cell disorders is particularly challenging for hematologists and emergency department (ED) physicians. We report two cases of acute hemolytic crisis in patients with previously unknown G6PD deficiency, where blood smear analysis played a key role in decision-making process. The trigger of acute hemolytic crisis was in both cases the recent intake of large amount of fava beans. Although Case 1 typically involved a male subject with unknown G6PD deficiency, Case 2 is of particular interest since the patient is a female with previously unknown G6PD deficiency. A recent study highlights the possible appearance of clinical signs for G6PD deficiency with aging in elder female population. Thus, hematologists should always take into account the possible lyonization effect on G6PD activity for G6PD deficiency inherited red cell disorder in the presence of unexplained acute hemolytic crisis in women with circulating hemi-ghosts.