MEH - Overproduction of blood cells

Question 1

Name three myeloproliferative disorders

Answer 1

Essential thrombocytopenia
Polycythaemia Vera
Myelofibrosis

Question 2

Where abouts is the disregulation for these kinds of disorders?

Answer 2

At the level of the haemopoietic stem cell

Question 3

What can myeloproliferative disorders lead to?

Answer 3

Leukaemia

Question 4

What mutation can patients have that can lead to MPD?

Answer 4

JAK2 (Janus kinase 2 gene) - causes increased proliferation and survival of haematopoietic precursors

Question 5

What are some reasons for increased haematocrit (3)?

Answer 5

Polycythaemia vera
Dehydration
increased Epo - either altitude or drug doping

Question 6

What occurs in PV?

Answer 6

High haematocrit OR raised red cell mass >25% above predicted
JAK2 mutation in 95% cases

Question 7

High haematocrit on blood test what you thinking?

Answer 7

PV or other cause explained above

Question 8

What body conditions/physiological causes can lead to increased Epo (and therefore increased haematocrit?)

Answer 8

Hypoxia - e.g. COPD
R - L shunts
Training at altitude
CO poisoning

Renal hypoxia - renal artery stenosis
Polycystic disease

Hepatocellular carcinoma (can produce Epo)
Renal cell carcinoma (can produce Epo)

Other tumours ?how

Question 9

What is the clinical presentation of PV?

Answer 9

Thrombosis - 40% present with IHD or CVA
Venous thrombosis
Pruritis (itchy)
Gout

Question 10

Why does PV predispose to gout?

Answer 10

Higher than normal turnover of RBC leading to higher than normal uric acid

Question 11

Can PV transform to myelofibrosis or acute leukaemia?

Answer 11

Yes both

Question 12

How do you treat PV?

Answer 12

Venesection

Aspirin