Causes of Polycythaemia

Question 1

Define polycythaemia

Answer 1

Elevated haematocrit (high concentration of RBCs) often leading to hyperviscosity of the blood and increased risk of thrombosis. Classed as primary and secondary.

Question 2

List the causes of primary polycythaemia

Answer 2

1) Polycythaemia rubra vera - a malignant proliferation of a clone derived from one pluripotent marrow stem cell (via mutation in JAK2).

More common aged >60yrs.

Question 3

List the causes of secondary polycythaemia

Answer 3

1) Hypoxia due to:
- Chronic lung disease
- Cyanotic congenital heart disease
- Altitude

2) Excess erythropoietin
- Adult polycystic kidney disease
- Renal cancer
- Ovarian cancer

Question 4

List signs associated with polycythaemia rubra vera

Answer 4

• Headaches, dizziness, tinnitus, visual disturbance
• Itch after a hot bath
• Erythromelalgia - burning sensation in fingers and toes
• Possible gout (due to increased urate due to high RBC turnover)
• Possible thrombosis: arterial (cardiac, cerebral, peripheral) or venous (DVT, cerebral, hepatic)