Myeloproliferative Disorders

Question 1

what are Myeloproliferative Disorders

Answer 1

Caused by proliferation and Cloning of myeloid progenitor cells in the bone marrow

While cells proliferate, they also maintain the ability to differentiate into RBC, WCC or platelets.

Question 2

Classification is by the type of cell that is proliferating

Answer 2

Red Cells - Polycythaemia Vera
WBC - CML
Platelets - Essential thrombocythaemia
Fibroblasts - Myelofibrosis

Question 3

Polycythaemia may be relative or absolute

Answer 3

Relative = Low plasma volume, normal RBC mass)
acute due to dehydration, Diuretics, alcohol
Chronic is assoc with obesity, increased alcohol intake and smoking

Absolute = increased RBC mass
Primary due to polycythaemia rubra vera
secondary due to Hypoxia - eg altitude, chronic lung disease, cyanotic heart disorder etc.)

Question 4

Polycythaemia Rubra Vera

Answer 4

Malignant clone of 1 pluripotent stem cell

JAK 2 mutation in 90%

Question 5

Signs of Polycythaemia Rubra Vera

Answer 5

may be assymptomatic and detected incidentally on FBC

Vague signs of hyperviscocity: Headache, Blurry vision, tinnitus

Aquagenic Pruritis due to excess histimine release

Erythromelalgia - Pain/blur in hands and feet

HSM
Gout

Increased risk of thrombosis

Question 6

Investigations of polycythaemia rubra vera

Answer 6

Jak 2 +ve
increased RBC, Hb, Hct, High RBC makes low EPO (-ve feedback)
Hypercellular BM

Question 7

Treatment of PRV

Answer 7

Aspirin
A-inteferon
Hydroxycarbamide

Question 8

Essential Polycythaemia

Answer 8

proliferation of megakaryoctes leads to persistently high platelets with abnormal function.

Question 9

Features of ET

Answer 9

Bleeding or A/V thrombosis and microvascular occlusion

head-ache
atypical chest pain
Light headed
Erythromelalgia

Question 10

Treatment of ET

Answer 10

Aspirin

hydroxycarbamide

Question 11

Myelofibrosis

Answer 11

Hyperplasia of megakaryocytes which produce platelet derived growth factor. This leads to massive BM fibrosis and myloid metaplasia (haemopoesis in spleen and liver –> massive HSM)

Question 12

Features of myelofibrosis

Answer 12

BM Failure
Abdo Discomfort with HSM
B symptoms

Question 13

investigation of myelofibrosis

Answer 13

Film: leukoerythroblastic cells and characteristic tear drop cells.

Question 14

Management of myelofibrosis

Answer 14

Supportive
Hydroxycarbamide

Allogenic Stem cell replacement may be curative