HEREDITARY SPHEROCYTOSIS

Question 1

Diagnostic Criteria

Answer 1

1. Family History AND Typical Blood Film Features AND DAT Negative 2. Equivocal Features —-> High Predictive Screening test such as a) EMA-Binding or b) Cryohaemolysis Test
   3. Atypical Cases —-> Gel electrophoresis of Erythrocyte Membranes / SDS-PAGE (Useful for CDA Type II diagnostics) Atypical = Phenotype worse than morphology; Patient worse than parent; Ensure clarified before splenectomy

Question 2

Management

Answer 2

Supportive Care – Folic Acid Supplementation / Red Cell Transfusion PRN

Splenectomy – Delay until at least aged 6; Counsel/Consent (sepsis); Vaccination; Cholecystectomy if symptomatic

Question 3

What is hereditary spherocytosis? (2)

Answer 3

• Autosomal dominant membranopathy
• Common in Northern Europe and America

Question 4

Presentation of hereditary spherocytosis (4)

Answer 4

• General anaemia
• Neonatal jaundice
• Splenomegaly
• Gall stones (50%)

Question 5

Pathophysiology of hereditary spherocytosis (3)

Answer 5

• Autosomal Dominant Deficiency in structural membrane protein spectrin
• Increased splenic recycling (extravascular haemolysis)
• Makes RBCs more spherical and rigid

Question 6

Diagnosis of hereditary spherocytosis (3)

Answer 6

• FBC and blood film: Normocytic, normochromic, spherocytes, increased reticulocytes
• Direct coombs -ve

Question 7

genes

Answer 7

Autosomal Dominan
ANK1 / SPTA1 / SPTB

Question 8

Investigations

Answer 8

+/- AnaemiaSpherocytosisPolychromasiaTarget CellsHowell Jolly BodiesThrombocytosisPlatelet Anisocytosis

EMA Binding:- EMA binds transmembrane proteins and fluoresces- Lack of fluorescence = Positive for Diagnosis

Cryohaemolysis Test:- HS red cells suscpetibile to cold in hypertonic solution