22 Myeloproliferative

Overview

• proliferation of cells of myeloid lineage

• myelofibrosis: overproduction of bone marrow fibrous tissues, low peripheral cell counts

Mutations

Polycythemia Vera

Pathogenesis

• increased resistance to flow, stasis, thrombosis

• histamine and PGE release after shower

• Budd Chiari: blood clot in hepatic vein

• excessive proliferation: bone marrow burned out

• progress to myeloid leukemia

Diagnosis

• diagnosis must exclude other causes

• hydroxyurea: converts RNA nucleotide to DNA nucleotide

Essential Thrombocytosis

• elevated platelet count

• must exclude polycythemia and CML

• iron deficiency anemia: protective mechanism against blood loss

• increased platelets but not functioning normally

• overactivity of platelets

Myelofibrosis

• primary: fibrous tissues overtaking bone marrow

• secondary: spent phase in polycythemia

Primary

• collagen overtakes bone marrow, pancytopenia

• cytokines from macrophages

• bone marrow fails, other organs take over jobs

• increased metabolism from extramedullary hematopoiesis and severe anemia

• immature precursor cells pushed out of bone marrow

Langerhan Histiocytosis

• langerhan: type of histiocyte

• malignant cells precursor myeloid cells, not really langerhan, just look like it

• tennis racket

• most severe: letterer-siwe

• least severe: eosinophilic granuloma, presenting with bone fracture and langerhan cells/eosinophils