Polycythaemia

• What is polycythaemia characterized by?


  An increase in haematocrit, red cell count, and haemoglobin concentration
• What are the two types of polycythaemia?


  Relative and absolute polycythaemia
• What are key signs and symptoms of polycythaemia?


  Fatigue, headache, visual disturbances, pruritus, and increased risk of thrombosis and haemorrhage
• What is the primary investigation for polycythaemia?


  A full blood count
• What management strategies are used for polycythaemia?


  Phlebotomy, hydration, and treatment of the underlying cause
• At what median age does polycythaemia typically present?


  55–60 years
• What is relative polycythaemia?


  It occurs when haemoglobin is elevated due to low plasma volume
• What conditions can lead to relative polycythaemia?


  Dehydration, chronic alcohol intake, excess diuretic use, pyrexia, and diarrhea/vomiting
• What is 'stress polycythaemia'?


  Relative polycythaemia found in middle-aged men with stressful occupations
• What is Gaisböck syndrome associated with?


  Hypertension and reduced plasma volume in young men, particularly smokers
• What defines absolute polycythaemia?


  Normal plasma volume with raised red cell mass
• What are the two classifications of absolute polycythaemia?


  Primary and secondary causes
• What characterizes primary polycythaemia?


  Excess and uncontrolled erythrocytosis independent of erythropoietin levels
• What gene mutation is commonly associated with primary polycythaemia?

  JAK2 gene mutation
• What is secondary polycythaemia driven by?


  Excess erythropoietin (EPO)
• What conditions can lead to secondary polycythaemia?


  Chronic hypoxia, anabolic steroid use, and inappropriate EPO secretion
• What are some symptoms of hyperviscosity in primary polycythaemia?


  Chest pain, myalgia, weakness, headache, blurred vision, and loss of concentration
• What is a common symptom of pruritus in polycythaemia?


  Typically occurs after a hot bath
• What is a sign of polycythaemia observed during examination?


  Facial redness (plethora)
• What is the significance of a full blood count in polycythaemia?


  It identifies elevated red cell count, haematocrit, and haemoglobin
• What might be raised in renal function tests for polycythaemia?


  Urate levels
• What is the role of EPO levels in polycythaemia diagnosis?


  EPO levels are often low in primary polycythaemia
• What is a common finding in bone marrow biopsy for polycythaemia?


  Hypercellular bone marrow
• Why is it important to exclude chronic myeloid leukaemia in polycythaemia?


  To ensure accurate diagnosis and treatment
• What is the target haematocrit level for primary polycythaemia management?


  Less than 45%
• What is venesection used for in polycythaemia management?


  To lower the red cell count rapidly
• What is a potential side effect of repeated venesection?


  Iron-deficient red blood cells with low haemoglobin content
• What is the first-line treatment for polycythaemia rubra vera?


  Regular venesection and aspirin 75mg daily
• What is hydroxycarbamide used for in polycythaemia management?


  To suppress erythrocytosis
• What is the second-line treatment for polycythaemia rubra vera?


  Interferon or JAK-2 inhibitors
• What is allopurinol used for in polycythaemia management?


  To treat gout/hyperuricaemia
• What are the specific clinical features of primary polycythaemia?


  • Hyperviscosity symptoms: Chest pain, myalgia, weakness, headache, blurred vision, loss of concentration
  • 'Ruddy complexion'
  • Splenomegaly
• What are the signs and symptoms of polycythaemia?


  • Fatigue
  • Headache
  • Visual disturbances
  • Pruritus
  • Erythromelalgia
  • Arterial and venous thrombosis
  • Haemorrhage
  • Increased risk of gout
  • Facial redness (plethora)
  • Splenomegaly
  • Hypertension
  • Peptic ulceration
• What are the investigations for polycythaemia?

  • Bedside: Pulse oximetry
  • Full blood count: Raised haematocrit, haemoglobin, red cell mass
  • Renal function and urate
  • Vitamin B12
  • EPO levels
  • JAK-2 V617F mutation
  • Bone marrow biopsy
  • Abnormal ultrasound
• What are the management strategies for polycythaemia?


  • Correct underlying causes
  • Maintain haematocrit <45% in primary polycythaemia
  • Maintain haematocrit <55% in secondary polycythaemia
  • Venesection
  • Hydroxycarbamide
  • Aspirin
  • Allopurinol
  • Interferon