Myeloproliferative disorders

--uncontrolled clonally proliferation of one or more cell lines in marrow

Polycythemia
-proliferation of RBCs
-Causes:
Primary: Polycythemia vera
Secondary: Hypoxia (chronic lung disease, congenital heart disease)
Relative: [Plasma volume dec.] Burns, dehydration (alcohol, diuretics)
-Treatment:
Aim to reduce PCV to below 45% by venesection

Myelofibrosis
-proliferation of fibroblasts
-Causes:
Intense marrow fibrosis with hemopoiesis in the spleen and liver
Other causes: any myeloproliferative disorder, TB, lymphoma
-Signs:
Pallor, Massive Splenomegaly, Petechiae & Purpura