A 30 year old presented with a skin lesion in his right axilla. A presumptive diagnosis of staphylococcal skin carbuncle is made & patient is treated with empiric trimethoprim/ sulfamethoxazole. After 2 days, the patient came to emergency with excessive weakness, abdominal pain & dark coloured urine. O/E- vitals are normal & jaundice is present. Lab studies show a drop in Hb from 14 g/dl to 8 g/dl & rise in bilirubin levels. Urine dipstick is positive for bilirubin. Peripheral blood smear is shown below. What could be the possible diagnosis of the patient?

PBF shows bite cells, anisocytosis, and spherocytes with jaundice after receiving sulfamethoxazole which makes the diagnosis of glucose 6-phosphate dehydrogenase (G6PD) deficiency. Triggers for acute haemolytic anemia in G6PD deficiency: Fava beans Infections Drugs- primaquine, dapsone, sulfamethoxazole, and nitrofurantoin Hemolytic attack stas with malaise, weakness, and abdominal or lumbar pain. After an interval of several hours to 2-3 days, the patient develops jaundice and often dark urine. Lab studies- hemoglobinemia, hemoglobinuria, high LDH, and low/absent plasma haptoglobin Diagnosed by semiquantitative or quantitative RBC tests or by DNA testing Hemolytic-uremic syndrome - cause microangiopathic hemolytic anemia with prominent schistocytes Iron deficiency- causes a microcytic and hypochromic anemia