Haemolytic anaemia

Question 1

Definition

Answer 1

• anaemia related to reduced RBC lifespan
• no blood loss
• no haematinic defiency

BONE MARROW IS NORMAL

Question 2

Role of Bm in compensating for haemolytic anaemia

Answer 2

• 120 days - HB normal
• 20-100d - Hb normal , reticulocytes increases, bilirubin increased( increased cell breakdown, unconjgated not seen in urine) Bone marrow compensates
• <20d - Hb decreased, reticulocytes up, bilirubin up, spleen up

Question 3

Classification of haemolytic anaemia

Answer 3

Congenital

• abnormalities of RBC membrane (hereditary spherocytosis)
• abnormalities of haemoglobin
• Enzyme defects- G6PD defiencies

Question 4

Hereditary spherocytosis

Answer 4

• autosomal dominant -like most structural defects
• RBCs spherocytic and polychromatic (increased reticulocytes)
• jaundice
• splenomegaly
• treatment if required - splenectomy

Question 5

Risk of removing a spleen

Answer 5

rise from encapsulated organisms pneumococcus, meningococcus, haemophillus

immunusation and long term penicillin

Question 6

Types of RBC enzyme defects

Answer 6

• Pyruvate kinase defiiency anaemia
  *

Question 7

Pyruvate kinase defieincy anaemia

Answer 7

• chronic extravascular haemolysis
• ATP depletion
• Autosomal recessive
• defiency of pyruvate kinase enzyme
• large amounts of 23DPG (acts to shift oxygen dissociation to the right, facilitates transfer of oxygen to tissues)
• patients still have good oxygen supply

Question 8

Glucose 6 phosphate dehydrogenase defieincy

Answer 8

• acute episodic intravascular haemolysis
• x-linked recessive
• acute haemolysis from oxidative stress
  
  • favism
  • drugs (antimalarias, sulphonamides)

Question 9

Acquired haemolytic anaemia can be

Answer 9

• Immune
  
  • autoimmune (warm or cold)
  • drug induced
  • issoimmune- haemolytic disease of the newborn
• non-immune
  
  • trauma
  • infection (malaria, speticaemia)

Question 10

Cold AIHA

Answer 10

• autoantigoby IgM
• “in the Middle of winter its cold IgM**
• causes
  
  • mycoplasma infection
  • idiopathic
• Red cell agglutinations

Question 11

Warm AIHA

Answer 11

• autoantibody IgG​
• Causes
  
  • idiopathic -30%
  • other autoimmne disease
  • lymphoproliferative disorder
  • drug induced
• blood film - Spehorocytic and polychromatic

Question 12

Drug indeced AIHA

Answer 12

1. Hapten
   
   • drug can attach as a hapten to
   • Red cell and hapten raise antibodies
   • Abs attack hapten/rbc complex
   • mild haemolytic state
2. Immune complex (innocent bystander)
   
   • drug is present
   • antibodies raised to it
   • Antibodies fix and complement and move across
   • Attach to the RBCs causing intravascular haemolysis
   • Severe haemolyssi - cephalopsorins!

Question 13

Direct coombs test

Answer 13

Warm AIH

• purpose test to detect warm IgG on RBC surface
• Direct coombs test!
• Add antbodies to IgG
• cause an immune lattic to form
• causing red cell agglutination

Question 14

Indirect coombs test

Answer 14

Cold AIH

• Uses patients plasma (antibodies) + 1 unit of blood that has bee crossmatched with the patient
• Sample of RED cell from unit of blood + sample of patients plasma into test tube
• if patients plasma contains ABs they will stick tot eh red cells
• Add antibodies to antibdies
• agglunitation forms
• Are there unexpected red cell antibodies!!!

Question 15

Treatment of COLD and WARM haemolytic anaemia

Answer 15

• Cold
  
  • Mycoplasma - self limiting
  • idiopathic- keep warm (antibodies stick to RBCS in cold areas)
• Warm
  
  • stop any drugs
  • steroids
  • immunosuppresion - azathioprine
  • splenectomy - if fails