Anaemia - Haemolytic Anaemia

Question 1

What is Haemolytic Anaemia?

Answer 1

Destruction of red blood cells, leading to low levels of Haemoglobin.

Question 2

Types of Inherited Haemolytic Anaemias (5).

Answer 2

1. Hereditary Spherocytosis (Membrane Defect).
2. Hereditary Elliptocytosis (Membrane Defect).
3. Thalassaemia (Haemoglobinopathy).
4. Sickle Cell Anaemia (Haemoglobinopathy).
5. G6PD Deficiency (Metabolism Defect).

Question 3

Types of Acquired Haemolytic Anaemias (5).

Answer 3

1. Autoimmune Haemolytic Anaemia (AIHA).
2. Alloimmune Haemolytic Anaemia (Transfusion Reactions, HDN).
3. Paroxysmal Nocturnal Haemoglobinuria.
4. Microangiopathic Haemolytic Anaemia.
5. Prosthetic Valve-Related Haemolysis.

Question 4

Clinical Features of Haemolytic Anaemias (3).

Answer 4

1. Anaemia.
2. Splenomegaly - Spleen is filled with destroyed RBCs.
3. Jaundice - Bilirubin is released with destruction of RBCs.

Question 5

Investigations of Haemolytic Anaemias (4).

Answer 5

1. FBC - Normocytic Anaemia.
2. Blood Film - Schistocytes (Fragments of RBCs).
3. Direct Coombs Test (AIHA).
4. LFTs - High Unconjugated Bilirubin, Raised LDH and Raised Urinary Urobilinogen.

Question 6

Pathophysiology of Intravascular Haemolytic Anaemia.

Answer 6

1. Blood Stream.
2. Release of Cellular Contents e.g. Hb into Circulation.
3. Excess Hb is removed by combining with Haptoglobin, Albuin (Methaemalbuminaemia), Loss in Urine (Haemoglobinuria) and Storage in Tubular Epithelial Cells and Shedding in Urine (Haemosiderinuria).

Question 7

Pathophysiology of Extravascular Haemolytic Anaemia (2).

Answer 7

1. Haemolysis in Reticuloendothelial System (Spleen and Liver).
2. No dramatic release of free Haemoglobin into circulation.

Question 8

Blood Results of Intravascular vs. Extravascular Haemolysis.

Answer 8

Identical :

1. Increased Unconjugated Bilirubin.
2. Increased LDH.
3. Increased Reticulocytes.

Differences :
Intravascular -
1. Decreased Haptoglobin.
2. Haemoglobinuria (Absent in Extravascular).
3. Haemoglobinaemia (Absent in Extravascular).
4. Haemosiderinuria (Absent in Extravascular).