🧪 G6PD Deficiency: The Hemolytic Anemia Triggered by Stress
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymatic disorder of red blood cells—affecting over 400 million people worldwide.
It causes hemolytic anemia in response to oxidative stress, and is a common vignette trigger in both Step 1 (enzymes, metabolism) and Step 2 (clinical diagnosis and management).
USMLE Tip: Think G6PD any time hemolysis follows infection, sulfa drugs, or fava beans.
🧬 Pathophysiology
G6PD is key in the pentose phosphate pathway, producing NADPH
NADPH maintains glutathione, which protects RBCs from oxidative damage
Without G6PD → ↑ oxidative stress → RBC membrane damage → intravascular hemolysis
🔥 Common Triggers
| Trigger Type | Examples |
|---|---|
| Infections | Pneumonia, hepatitis, malaria |
| Drugs | Sulfonamides, dapsone, antimalarials, nitrofurantoin |
| Foods | Fava beans |
| Stress | DKA, hypoxia, surgery |
🧪 Lab Findings
| Test | Result |
|---|---|
| Hemoglobin | ↓ |
| LDH | ↑ |
| Haptoglobin | ↓ |
| Reticulocyte count | ↑ |
| Peripheral Smear | Bite cells, Heinz bodies |
| G6PD assay | ↓ (not during acute crisis) |
🩸 Peripheral Smear Findings
Heinz bodies → denatured hemoglobin (seen with supravital stain)
Bite cells → splenic macrophage removal of Heinz bodies
👀 Buzzwords for USMLE: "Back from vacation in Greece," "ate fava beans," "sudden jaundice after sulfa antibiotics."
🧑⚕️ Management
Avoid triggers (especially offending drugs)
Supportive care: hydration, oxygen
Rarely transfusion if severe
Genetic counseling in affected families
📚 Sample USMLE Vignette
A 24-year-old male of Mediterranean descent develops jaundice and dark urine after taking trimethoprim-sulfamethoxazole for a UTI. Blood smear shows bite cells. What’s the most likely diagnosis?
✅ Answer: G6PD deficiency
🖼 KOTC Science Visual Coming Next…
We’ll now generate your 1200x800 feature image with a visual breakdown of the enzyme pathway, triggers, smear findings, and treatment pearls.
🔗 Access 1,000+ science concept visuals at mcat.kingofthecurve.org
📲 Call to Action
⛑ Don’t get blindsided by oxidative stress on test day.
💡 Download the King of the Curve App for:
Daily Step 1 + Step 2 questions
Bite-sized science illustrations
Multiplayer battles + Curve Coins
Rapid review tools on-the-go
Frequently Asked Questions (FAQs)
-
Aim for 4-6 focused hours, ensuring you incorporate breaks to avoid burnout.
-
Practice mindfulness techniques, take practice exams under realistic conditions, and maintain a balanced lifestyle.
-
Set short-term goals, seek support from mentors, and reward yourself for small achievements.
-
Regular exercise improves focus, reduces stress, and enhances overall mental clarity.
-
KOTC offers personalized learning tools, gamification features, and adaptive question banks to help students stay on track without burnout.
