Myeloproliferative Disorders & High Blood Counts

What Are Myeloproliferative Disorders?

Myeloproliferative disorders (MPDs), also known as myeloproliferative neoplasms (MPNs), are conditions where the bone marrow produces too many red blood cells, white blood cells, or platelets. These disorders can increase the risk of blood clots, bleeding complications, and, in some cases, progression to more serious conditions.

Common Types of Myeloproliferative Disorders:

  • Polycythaemia Vera (PV): Excess red blood cell production, increasing the risk of blood clots, headaches, dizziness, and high blood pressure.

  • Essential Thrombocythemia (ET): Overproduction of platelets, which may cause abnormal clotting or, paradoxically, bleeding.

  • Primary Myelofibrosis (PMF): A condition where excessive blood cell production leads to bone marrow scarring, anaemia, and an enlarged spleen.

  • Chronic Myeloid Leukaemia (CML): A form of blood cancer characterised by excessive white blood cell production, usually associated with a genetic mutation called the Philadelphia chromosome.

Symptoms of High Blood Counts or MPDs

  • Polycythaemia (High Red Blood Cells):

    • Headaches, dizziness, visual disturbances

    • High blood pressure

    • Red or flushed complexion

    • Itching, especially after a warm bath or shower

    • Increased risk of blood clots (deep vein thrombosis, stroke, or heart attack)

  • Thrombocytosis (High Platelets):

    • Increased risk of clotting (e.g., stroke, heart attack, or deep vein thrombosis)

    • Occasional bleeding symptoms (nosebleeds, bruising)

  • Leukocytosis (High White Blood Cells):

    • Often asymptomatic but may indicate an underlying blood disorder if persistent

Investigations for High Blood Counts

As a haematologist, I conduct detailed investigations to determine the cause of high blood counts. These may include:

1. Blood Tests

  • Full Blood Count (FBC): Measures red cells, white cells, and platelets.

  • JAK2, CALR, MPL Genetic Tests: Identify mutations commonly found in myeloproliferative disorders.

  • BCR-ABL Testing: A genetic test to check for chronic myeloid leukaemia (CML).

  • Erythropoietin (EPO) Level: Helps differentiate between primary and secondary causes of high red blood cell counts.

  • Iron Studies & Inflammatory Markers: To exclude secondary causes of polycythaemia or reactive thrombocytosis.

2. Bone Marrow Investigation (If Required)

  • Bone Marrow Aspiration & Biopsy: Examines blood cell production in the bone marrow, particularly for diagnosing primary myelofibrosis or confirming an MPN diagnosis.

The Role of a Haematologist

My role includes:

  • Diagnosing and confirming whether high blood counts are due to a myeloproliferative disorder or a secondary cause.

  • Personalised treatment planning, which may include:

    • Aspirin or Antiplatelet Therapy – To reduce clotting risk in PV and ET.

    • Venesection (Blood Removal Therapy) – Used in PV to reduce blood thickness and lower clot risk.

    • Cytoreductive Therapy (e.g., Hydroxycarbamide, Interferon, or Ruxolitinib) – To manage blood counts and control thrombotic risk

    • Long-term monitoring to assess disease progression and prevent complications.