Epidemiology

Etiology

Pathophysiology

Clinical features

• Anemia and pallor
• Jaundice (due to ↑ unconjugated bilirubin)
• Splenomegaly with left upper quadrant pain
• Black pigment gallstones (made of calcium bilirubinate), may lead to cholecystitis

Diagnostics

• Normocytic anemia: mean cell volume (MCV) within normal range (80-100 fL) or slightly decreased
• Increased mean corpuscular hemoglobin concentration (MCHC)
  • The increase in MCHC is the result of a decrease in RBC cell volume (caused by a decrease in RBC water content), whereas the hemoglobin content remains constant.
• ↑ Red blood cell distribution width (↑ RDW)
  • This finding is highly suggestive of HS!
• ↑ Reticulocytes (normal range: 0.5%–1.5% of total RBC count)
• Findings of hemolytic anemia
  • ↑ Unconjugated bilirubin
  • ↓ Haptoglobin
  • ↑ LDH
• Eosin-5-maleimide binding test (EMA binding test)
  • Test of choice, as results are readily available (within two hours)
  • Decreased binding between dye (eosin-5-maleimide) and RBC membrane proteins
  • Binding is quantified using flow cytometry, which shows decreased mean fluorescence
• Positive osmotic fragility test

Treatment