Hereditary spherocytosis

Background

  • Hereditary hemolytic anemia due to defect in RBC cell membrane (mainly spectrin, ankyrin)
    • 75% Autosomal Dominant, 25% Autosomal Recessive

Pathophysiology

  • Deficient/Nonfunctional RBC cell membrane proteins that connect the cell membrane skeleton to the lipid bilayer

Clinical Features

  • Classic triad: Anemia, Jaundice, Splenomegaly

Mild

  • No anemia, normal retic count, little or no jaundice/splenomegaly
  • No RBC transfusions
  • Dx’d later in life

Moderate

  • Anemic, elevated retic, elevated bili, maybe splenomegaly
  • May require RBC transfusions
  • Dx’d in infancy or early childhood

Severe

  • Marked hemolysis, anemia, hyperbili, splenomegaly
  • Require regular RBC transfusions
  • Dx’d in infancy

Differential Diagnosis

Microangiopathic Hemolytic Anemia (MAHA)

Evaluation

  • Low hemoglobin, elevated retic count, spherocytes on peripheral smear
  • Elevated MCHC (RBC membrane leaky causing RBC dehydration)
  • Osmotic fragility test, AGLT, EMA binding test, cryohemolysis
    • One study showed AGLT + EMA binding test identified all HS patients
  • Negative Coombs test

Management

  • Folic acid
  • RBC transfusion
  • EPO
  • Splenectomy
    • As late as possible, preferably >6 yo
    • Post-op need encapsulated bacteria prophylaxis: Strep Pneumo, H Influenza, Neiserria Meningitidis
    • Possible higher risk of arterial/venous thrombosis in HS after splenectomy
  • Hematopoietic cell transplant (most agree risks outweigh benefits)

Complications

  • Cholelithiasis secondary to intravascular hemolysis causing development of bilirubin gallstones
  • Pseudohyperkalemia: K+ leaks out of RBCs after blood draw

See Also

Authors:

Ross Donaldson