G6PD Deficiency: The Daily PANCE Blueprint
A 23-year-old African-American man develops jaundice and dark urine after taking trimethoprim-sulfamethoxazole. What’s the most likely finding on smear?
A. Spherocytes
B. Heinz bodies
C. Target cells
D. Schistocytes
E. Howell-Jolly bodies
Answer and topic summary
The answer is B. Heinz bodies
Heinz bodies are precipitated oxidized hemoglobin seen in G6PD deficiency, which impairs the red blood cell’s ability to neutralize oxidative stress. This patient’s hemolysis after exposure to an oxidative drug (TMP-SMX) is classic for glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked recessive disorder more common in males of African, Mediterranean, or Asian descent. G6PD protects RBCs from oxidative damage by producing NADPH; without it, oxidant stress (from infection, fava beans, or sulfa drugs) causes hemoglobin denaturation and membrane damage. Heinz bodies are best visualized with supravital staining, and they contribute to bite cells as the spleen removes them.
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Smarty PANCE Content Blueprint Review:
Covered under ⇒ PANCE Blueprint Hematology ⇒ ⇒ ⇒
Also covered as part of the Internal Medicine Rotation topic list
