Polycythaemia

Question 1

What is polycythaemia?

Answer 1

A condition characterised by an elevated haematocrit and/or haemoglobin concentration

Polycythaemia can be classed as primary, secondary, or relative.

Question 2

What are the three types of polycythaemia?

Answer 2

• Primary
• Secondary
• Relative

Primary is also known as polycythaemia vera.

Question 3

What is primary polycythaemia called?

Answer 3

Polycythaemia vera

It is a myeloproliferative disorder.

Question 4

What causes polycythaemia vera?

Answer 4

Clonal proliferation of marrow stem cells leading to increased red cell volume

Often accompanied by overproduction of neutrophils and platelets.

Question 5

What mutation is present in 95% of polycythaemia vera patients?

Answer 5

JAK2 mutation

This mutation is key in the pathophysiology of the disease.

Question 6

What is a significant complication of hyperviscosity in polycythaemia?

Answer 6

Increased risk of thrombotic events

Examples include DVT, PE, arterial thrombosis (stroke, MI).

Question 7

What are some clinical features of polycythaemia vera?

Answer 7

• Pruritis (typically after hot bath)
• Splenomegaly
• Hyperviscosity
• Haemorrhage (secondary to abnormal platelets)
• Plethoric appearance
• Hypertension (in 1/3 patients)

These features help in the clinical diagnosis of the condition.

Question 8

What investigations are commonly performed for polycythaemia vera?

Answer 8

• FBC (raised haematocrit, neutrophils, eosinophils, platelets)
• JAK2 mutation test
• Serum ferritin
• Renal and liver function tests

These tests help confirm the diagnosis and assess the severity.

Question 9

What is the first-line management for polycythaemia vera?

Answer 9

Venesection

This is aimed at reducing red blood cell mass and improving symptoms.

Question 10

What medication may increase the risk of secondary leukaemia in polycythaemia vera management?

Answer 10

Hydroxyurea

It is used for managing the condition but carries risks.

Question 11

What are potential complications of polycythaemia vera?

Answer 11

• 5-15% progress to myelofibrosis
• 5-15% progress to acute leukaemia

These complications highlight the importance of monitoring and management.

Question 12

Relative causes of polycythaemia

Answer 12

• Dehydration
• Stress (Gaisbock syndrome)

Question 13

Secondary causes of polycythaemia

Answer 13

• COPD
• Altitude
• Obstructive sleep apnoea
• Excess erythropoeitin (e.g. hypernephroma)