22 Myeloproliferative

  • 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