Anaemia - Hereditary Spherocytosis

Question 1

Outline the epidemiology of hereditary spherocytosis (HS) (2).

Answer 1

• Most common in people of Northern European ancestry
• Preesents in infancy (hereditary)

Question 2

What are the risk factors of hereditary sphercoytosis (HS) (4)?

Answer 2

• Fx of:
  
  • Splenectomy
  • Anaemia
  • Jaundice
• Northen European ancestry

Question 3

Outline the pathogenesis of hereditary spherocytosis (HS) (2).

Answer 3

1. HS is an inherited disorder resulting in defects in the skeletal proteins of the red-cell membrane
2. These proteins are normally responsible for maintaining the red-cell shape and deformability

• Defects may occur in any of the 5 different membrane skeleton proteins:
  
  • Alpha-spectrin
  • Beta-spectrin
  • Ankyrin
  • Band 3 protein
  • Protein 4.2

Question 4

Outline the pathophysiology of hereditary spherocytosis (HS) (5).

Answer 4

1. Defects in membrane structural proteins result in a weakening of vertical linkages between membrane surface proteins and the phospholipid bilayer.
2. There is a loss of surface membrane area relative to volume
3. This alters the red-cell shape (so as to become spherical) and reduces its flexibility
4. The spherocytes are fragile and are selectively removed by, and destroyed in, the spleen
5. The increased rate of red-cell destruction typically results in hyperbilirubinaemia, an elevated reticulocyte count, and splenomegaly

Question 5

How would a patient with hereditary spherocytosis (HS) present (5)?

Answer 5

Common:
* Presence of risk factors (Fx)
* Pallor
* Jaundice
* Splenomegaly
* Fatigue

Uncommon:
* Hydrops foetalis or stillbirth

Question 6

What investigations are recommended in suspected hereditary spherocytosis (HS) (6)?

Answer 6

• FBC
• Reticulocyte count
• Blood smear
• Serum bilirubin
• Serum aminotransferases
• Direct anti-globulin test (DAT)

Question 7

What would is the diagnostic result of FBC in hereditary spherocytosis (HS)?

• Hb
• MCHC
• MCV
• Platelet
• WBC count

Answer 7

• Hb: reduced or may be normal
• MCHC: may be elevated
• MCV: normal or reduced
• Platelet and WBC count: usually normal (with concurrent viral infection may be reduced)

Question 8

What would is the diagnostic result of reticulocyte count in hereditary spherocytosis (HS)?

Answer 8

Elevated

Question 9

What would is the diagnostic result of blood smear in hereditary spherocytosis (HS)?

Answer 9

Spherocytes present

Blood smear of patient with HS (A) compared with normal blood smear (B); Pincer cell (mushroom-shaped cell) indicated

May also demonstrate pincer cells

Question 10

What would is the diagnostic result of serum bilirubin in hereditary spherocytosis (HS)?

Answer 10

Elevated unconjugated bilirubin

Question 11

What would is the diagnostic result of serum aminotransferases in hereditary spherocytosis (HS)?

Answer 11

Usually normal

Question 12

What would is the diagnostic result of direct anti-globulin test (DAT) in hereditary spherocytosis (HS)?

Answer 12

Negative

Question 13

What is the management of a neonate (< 28 days old) with hereditary spherocytosis (HS) without jaundice (2 + 1)?

Answer 13

Supportive care ± red blood cell transfusions

Adjuvant:
* Folic acid supplementation

Question 14

What is the management of a neonate (< 28 days old) with hereditary spherocytosis (HS) with jaundice (2 + 2)?

Answer 14

Supportive care ± red blood cell transfusions

Adjuvant:
* Folic acid supplementation
* Phototherapy or exchange transfusion

Question 15

What is the management of an infant (< 28 days old) with severe hereditary spherocytosis (HS) (2 + 1)?

Answer 15

Supportive care ± red blood cell transfusions

Adjuvant:
* Folic acid supplementation

Question 16

What is the management of an infant (< 28 days old) with mild-to-moderate hereditary spherocytosis (HS) (2 +1)?

Answer 16

Supportive care ± red blood cell transfusions

Adjuvant:
* Folic acid supplementation