Haemolytic Anaemia (3)

Question 1

How does it present?

What are the ways in which it’s classified?

Answer 1

➊ • Anaemia
• Splenomegaly - Spleen filled with destroyed RBCs
• Jaundice - Due to increased Bilirubin
• Pigmented Gallstones - Due to increased Bilirubin

➋ • Hereditary or Acquired
• Intravascular or Extravascular (liver/spleen)
• Autoimmune (Coombs +ve) or Non-autoimmune (Coombs -ve)

Question 2

What are the hereditary causes?

What are the acquired causes?

Answer 2

➊ • Sickle cell
• Thalassaemia
• Hereditary Spherocytosis (Membrane disorder)
• G6PD Deficiency

➋ • Autoimmune haemolytic anaemia/AIHA (Warm, Cold, Drug-induced)
• Non-autoimmune haemolytic anaemia (Transfusion reactions, Haemolytic Disease of Newborn)
• Microangiopathic Haemolysis (MAHA)
• Paroxysmal Nocturnal Haemoglobinuria (PNH)
• Metallic heart valve - sheer stress causes haemolysis

Question 3

What is involved in the Haemolytic Screen?

Answer 3

• FBC - Normocytic anaemia
• Blood film - Spherocytes/Schistocytes (RBC fragments)
• LDH - Raised due to cell turnover
• Reticulocytes - Raised as bone marrow tries to compensate
• Bilirubin - Raised

N.B Increased Reticulocytes + Bilirubin is an indicator of Haemolysis

• Haptoglobin - Decreased in intravascular haemolysis as it’s used to bind to the Hb

N.B. Main way to differentiate between Intravascular and Extravascular haemolysis

• DAT/Coombs Test - +ve in autoimmune type

Question 4

Autoimmune Haemolytic Anaemia (AIHA):
How is it diagnosed?
→ What is expected to be seen?

What are its 2 types?

What often triggers Cold AIHA?

How is Warm AIHA managed?

Answer 4

➊ DAT/Coombs test +ve
→ Aggultination

➋ Based on the temp at which its autoantibodies function to cause RBC destruction
• Warm - IgG-mediated, in which the spleen tags cells for splenic phagocytosis (extravascular)
• Cold - IgM-mediated, in which complement is bound for RBC destruction (intravascular)

➌ Viral infection (occurs 2-3 wks after)

➍ Transfusions, Steroids, Rituximab, Splenectomy

Question 5

What occurs in Microangiopathic Haemolytic Anaemia (MAHA)?

What occurs in Paroxysmal Nocturnal Haemoglobinuria (PNH)?

Answer 5

➊ • Intravascular haemolytic disorder - Structural abnormalities of small blood vessels causing mechanical RBC destruction, leading to the formation of Schistocytes (cell fragments)
• Can be primary, but usually secondary to an underlying condition e.g. HUS, TTP, or DIC

➋ Rare acquired stem cell disorder where an abnormal surface glycoprotein on RBCs marks them for complement-mediated haemolysis