Makindo Medical Notes.com

Related Subjects: |Iron deficiency Anaemia |Haemolytic anaemia |Macrocytic anaemia |Megaloblastic anaemia |Microcytic anaemia |Myelodysplasia |Myelofibrosis

The most frequent cause is a mutation in the spectrin gene. Spectrin is a component of the RBC membrane, as are actin, ankyrin and protein 4.1, mutations in all of which are less frequently responsible for the condition.

About

• Autosomal dominant condition though 25% are de novo mutations
• The main result of haemolytic anaemia is the reduction of red cell half-life and anaemia
• Commonest cause of inherited haemolytic anaemia in Europe
• Seen in > 1 in 5000 but often goes undetected

Aetiology

• There is a deficiency of beta spectrin or ankyrin in the RBC cytoskeleton
• The RBC becomes more rigid alters its flexibility
• Cells are removed from the circulation mainly by the spleen

Clinical

• Haemolytic crisis precipitated by infection
• There is a great deal of variability
• Anaemia - chronic haemolysis
• Megaloblastic crises due to folate deficiency
• Splenomegaly, Jaundice, Leg ulcers, Pigment gallstones
• Aplastic anaemia can result after infection with Parvovirus B19

Investigations

• Megaloblastic anaemia often due to folate deficiency
• MCHC is usually elevated
• Increased LDH, Increased reticulocytes, DAT/Coomb's negative
• Diagnosed on Blood film + evidence of fragility when placed in hypotonic solution
• May be confirmed by flow cytometry

Management

• Oral folate supplementation 5 mg once weekly and splenectomy
• Splenectomy usually after childhood (6 years old) which reduces red cell break down and improves the lifespan of erythrocytes
• Splenectomy has a risk of pneumococcal infection and patients need to remain on Penicillin
• Hereditary elliptocytosis has a similar cytoskeleton defect but clinically is far less severe and needs no treatment

Post splenectomy

• Thrombocythemia which may be transient and may need Aspirin, Infection with encapsulated organisms.
• Prevention of Infection post-splenectomy
  • Vaccination against Pneumococcus pre splenectomy
  • Vaccination against Haemophilus Influenza type b pre splenectomy
  • Meningococcal C vaccine and A vaccine to those going to endemic areas
  • Penicillin V 500 mg bd possibly life long