A 20-year-old man comes to the emergency department due to a 2-day history of increasing tiredness and exertional dyspnea. He also reports yellowish discoloration of the eyes and dark urine. The patient has no chronic medical conditions, but 5 days ago, he went to an urgent care clinic due to right leg cellulitis; a 7-day course of trimethoprim-sulfamethoxazole was prescribed. The cellulitis has improved. The patient, an exchange student from Israel, does not use tobacco, alcohol, or illicit drugs. Temperature is 37 C (98.6 F) , blood pressure is 116/76 mm Hg, and pulse is 104/min. Physical examination shows mild scleral icterus, pale oral mucous membranes, a faint systolic ejection murmur, and a nontender abdomen with no organomegaly. Hemoglobin is 7.4 g/dL and mean corpuscular volume is 90 µm³. Which of the following additional findings are most likely present in this patient?

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11ec160b_3af1_8221_9249_b5d417f0a0c6_MD0001_00 This patient has anemia and signs of hemolysis (eg, dark urine, scleral icterus) after taking a sulfa drug (ie, trimethoprim-sulfamethoxazole), findings consistent with glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD is a red blood cell (RBC) enzyme that helps neutralize reactive oxygen species by producing NADPH. In the absence of G6PD, oxygen radicals accumulate during times of oxidative stress (eg, infection, sulfa drugs, fava bean ingestion), causing damage to RBCs and intravascular hemolysis. Characteristic findings of hemolysis include the following: G6PD deficiency can be differentiated from other hemolytic anemias by the presence of Heinz bodies (inclusions of denatured hemoglobin) and bite cells (caused by phagocytic removal of Heinz bodies) on peripheral smear. Low G6PD activity within RBCs is diagnostic; however, this test may be inaccurate during an acute episode due to increased reticulocytes. Management generally involves avoiding known hemolytic triggers. Educational objective: Glucose-6-phosphate dehydrogenase deficiency presents with signs of anemia (eg, fatigue, pallor) and hemolysis (eg, jaundice, dark urine) after oxidative stress (eg, sulfa drug). Hemolysis is associated with reticulocytosis, increased lactate dehydrogenase, decreased haptoglobin, and elevated indirect bilirubin. __________ References: Glucose-6-phosphate dehydrogenase deficiency. (http://www.ncbi.nlm.nih.gov/pubmed/27040960)

A 20-Year-Old Man Comes to the Emergency Department Due to a 2-Day