Membrane hemolysis vs Enzyme hemolysis
How to tell Membrane hemolysis and Enzyme hemolysis apart when a board question makes them look alike.
Spherocytosis is membrane/splenic extravascular hemolysis; G6PD is oxidant-triggered Heinz/bite hemolysis; pyruvate kinase is ATP-defect chronic hemolysis.
Side by side
Hereditary spherocytosis causes extravascular hemolysis, jaundice, splenomegaly, pigmented gallstones, high MCHC, spherocytes, and increased osmotic fragility.
G6PD deficiency causes episodic oxidative intravascular hemolysis with bite cells and Heinz bodies; pyruvate kinase deficiency causes chronic hemolysis with echinocytes and increased 2,3-BPG.
Spectrin, ankyrin, band 3, or protein 4.2 defects weaken RBC membrane skeleton, producing spherocytes removed by splenic macrophages.
G6PD impairs NADPH/glutathione defense against oxidants; pyruvate kinase impairs ATP generation needed for RBC membrane function.
Spherocytes, high MCHC, negative Coombs test, and increased osmotic fragility support hereditary spherocytosis.
Heinz bodies and bite cells after oxidant stress support G6PD deficiency; echinocytes and increased 2,3-BPG support pyruvate kinase deficiency.
The trap
All are intrinsic RBC hemolysis, so smear shape, trigger, and pathophysiology separate them.
Watch it explained
The repair move
For inherited hemolysis, anchor on membrane shape, oxidant trigger, or ATP failure.
Try a free question
CoreA patient has jaundice, splenomegaly, pigmented gallstones, spherocytes, high MCHC, negative Coombs test, and increased osmotic fragility. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Hereditary spherocytosis. Spherocytes with high MCHC, negative Coombs test, splenomegaly, and increased osmotic fragility point to hereditary spherocytosis.
Why the other choices are tempting
- B. G6PD deficiency has oxidant-triggered hemolysis with Heinz bodies and bite cells.
- C. Pyruvate kinase deficiency causes ATP-defect hemolysis with echinocytes.
- D. Autoimmune hemolytic anemia can show spherocytes but should have a positive Coombs test.
- E. Sickle cell disease has HbS polymerization and sickled cells.
Flashcards
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What smear clue points to hereditary spherocytosis?
Spherocytes with high MCHC and negative Coombs test point to hereditary spherocytosis.
What smear clue points to G6PD deficiency?
Heinz bodies and bite cells after oxidative stress point to G6PD deficiency.
Quick answers
What is the fastest way to tell Membrane hemolysis from Enzyme hemolysis?
Spherocytosis is membrane/splenic extravascular hemolysis; G6PD is oxidant-triggered Heinz/bite hemolysis; pyruvate kinase is ATP-defect chronic hemolysis.
What is the key clue for Membrane hemolysis?
Hereditary spherocytosis causes extravascular hemolysis, jaundice, splenomegaly, pigmented gallstones, high MCHC, spherocytes, and increased osmotic fragility.
What is the key clue for Enzyme hemolysis?
G6PD deficiency causes episodic oxidative intravascular hemolysis with bite cells and Heinz bodies; pyruvate kinase deficiency causes chronic hemolysis with echinocytes and increased 2,3-BPG.
What is the common trap with Membrane hemolysis vs Enzyme hemolysis?
All are intrinsic RBC hemolysis, so smear shape, trigger, and pathophysiology separate them.