Polycythaemia

Polycythaemia refers to an abnormal increase in red blood cell mass. It is common in cyanotic congenital heart diseases.

Types:

A. Primary polycythaemia (Polycythaemia Vera):

– Caused by a mutation in the JAK2 gene, leading to uncontrolled red blood cell production.

– May also increase white blood cells and platelets.

B. Secondary polycythaemia:

– Caused by increased erythropoietin production due to chronic hypoxia (e.g., in lung diseases or high-altitude living) or tumours.

Symptoms:

• headache
• dizziness
•  visual disturbances
• pruritus
• increased risk of thrombosis

Diagnosis:

Elevated haematocrit and haemoglobin levels.

Testing for JAK2 mutations in polycythaemia vera.

Treatment:

• Phlebotomy to reduce red blood cell mass.
• Hydroxyurea or interferon in polycythaemia vera.
• Treating underlying causes in secondary polycythaemia.