Myeloproliferative disorder

Question 1

Types

Answer 1

Over proliferation of myeloid cells:

Primary myelofibrosis (no dominant cell line, characteristic bone marrow fibrosis)

Polycythaemia vera (RBC)

Essential thrombocythaemia

Question 2

Polycythemia Ruba Vera

Clinical Features

Answer 2

hyperviscosity

pruritus, typically after a hot bath

splenomegaly

haemorrhage (secondary to abnormal platelet function)

plethoric appearance (flushing)

Question 3

Polycythaemia Ruba Vera

Investigations

Answer 3

FBC; raised Hb

Blood film

JAK2 mutation

Serum ferritin

U+Es and LFTs

If JAK 2 negative:

• serum erythropoietin level (which would be normal in polycythaemia vera)
• bone marrow aspirate and trephine (for myeloma\0
• cytogenetic analysis

Question 4

Polycythaemia Vera

Management

Answer 4

Aspirin

Venesection - first line treatment

Hydroxyurea -slight increased risk of secondary leukaemia

Phosphorus-32 therapy

Question 5

Essential Thrombocytosis

Features

Answer 5

platelet count > 600 * 109/l

both thrombosis (venous or arterial) and haemorrhage can be seen

a characteristic symptom is a burning sensation in the hands

a JAK2 mutation is found in around 50% of patients

Question 6

Essential Thrombocytosis

Management

Answer 6

Hydroxyurea (hydroxycarbamide) is widely used to reduce the platelet count

Interferon-α is also used in younger patients

Low-dose aspirin may be used to reduce the thrombotic risk

Question 7

Myelofibrosis

Pathology

Answer 7

Bone marrow is replaced with collagen (due to proliferation of megakaryocytes which releases fibroblast growth factor and stimulates collagen formation)

Can happen primarily or secondary due to e.g. leukaemia

Question 8

Myelofibrosis

Clinical Features

Answer 8

Elderly person with symptoms of anaemia e.g. fatigue (the most common presenting symptom)

Massive splenomegaly: e.g. early satiety

Hypermetabolic symptoms due to the cytokines from megakaryocytes being released into system: weight loss, night sweats etc

Question 9

Myelofibrosis

investigation

Answer 9

Anaemia

High WBC and platelet count early in the disease

‘tear-drop’ poikilocytes on blood film: due to RBC squeezing themselves out of the fibrotic bone marrow

Unobtainable bone marrow biopsy - ‘dry tap’ therefore trephine biopsy needed

High urate and LDH (reflect increased cell turnover)

Question 10

Myelofibrosis

Management

Answer 10

Mostly palliative