Haemolytic anaemia

Question 1

Define:

Answer 1

• Premature erythrocyte breakdown causing shortened erythrocyte life span (< 120 days) with anaemia

Question 2

What are the two main types:

Answer 2

Occurs in the circulation to damaged RBCs (intravascular) or in the reticuloendothelial system i.e. macrophages of liver, spleen and bone marrow remove defective RBCs (extravascular

Question 3

Aetiology/risk factors:

Answer 3

• Hereditary - Membrane Defects (Hereditary spherocytosis + Hereditary elliptocytosis)

Metabolic Defects (G6PD deficiency , Pyruvate kinase deficiency)

Haemoglobinopathies( Sickle cell disease ,Thalassemia)

o Autoimmune (Antibodies attach to erythrocytes causing intravascular and extravascular haemolysis)

Isoimmune( transfusion reaction + Haemolytic disease of the newborn)

o Drugs – cause formation of RBC autoantibodies from…
• Penicillin – binding to RBC membranes
• Quinine – production of immune complexes
•
o Trauma
• Microangiopathic haemolytic anaemia (caused by RBC fragmentation in abnormal microcirculation – intravascular)
 E.g. haemolytic uraemic syndrome, DIC, malignant hypertension

Infection (Malaria and Sepsis)

Question 4

What is G6PD?

Answer 4

– G6PD is part of the pentose shunt pathway which is designed to protect against oxidants found in drugs, chemicals etc
X-linked
Most common enzyme effect
Must avoid oxidants – broad beans, mothballs, henna

Question 5

What is pyruvate kinase deficiency:

Answer 5

– pyruvate kinase is required at the last stage of glycolysis so deficiency causes RBCs with decreased ATP

Question 6

Epidemiology:

Answer 6

Common

Genetic causes more in Africa and the middle east

Hereditary spherocytosis (most common in europe)

Question 7

Symptoms:

Answer 7

Jaundice 
Anaemia 
Haematuria
FHx
Asymp
Travel 
Dark urine 
Race

Question 8

Signs:

Answer 8

Jaundice
Hepatosplenomegaly
Pallor
Leg ulcers due to poor blood flow

Question 9

Investigations:

Answer 9

o FBC:

o U&Es
o Folate
• Blood Film

• Urine

• Direct Coombs’ Test
o Tests for autoimmune haemolytic anaemia

• Osmotic fragility test or Spectrin mutation analysis
o Identifies membrane abnormalities

Ham’s test
• Hb Electrophoresis or Enzyme Assays
o To exclude other causes
• Bone Marrow Biopsy (rarely performed)

Question 10

Finding on bloodfilms:

Answer 10

o Leucoerythroblastic picture
o Macrocytosis
o Nucleated erythrocytes or reticulocytes
o Polychromasia
o May identify specific abnormal cells pointing to the diagnosis such as:
Hypochromic microcytic anaemia - thalassemia
• Spherocytes – hereditary spherocytosis or AIHA
• Elliptocytes – hereditary elliptocytosis
• Sickle cells – sickle cell anaemia
• Schistocytes - MAHA
• Malarial parasites
• Heinz bodies (‘bite cells’) – G6PD deficiency

Question 11

What are findings on FBC:

Answer 11

• Low Hb
• High reticulocytes
• High MCV
• High unconjugated bilirubin
• Low haptoglobin (a protein that binds to free Hb released by red blood cells)

Question 12

Findings in urine:

Answer 12

o High urobilinogen
o Haemoglobinuria
o Haemosiderinuria