myeloproliferative disorders Flashcards
(19 cards)
myeoproliferative disorders
uncontrolled proliferation of a single type of stem cell
considered form of cancer but v slow progressing
–> can transform into acute myeloid leukaemia
main 3 myeloproliferative disorders and their proliferating cell line
myelofibrosis - haematopoietic stem cells
polycythaemia vera - erythroid cells
essential thrombocythaemia - megakaryocyte
pathophys of myelofibrosis
caused by hyperplasia of abnormal megakaryocytes
-> the resultant release of platelet derived growth factor is thought to stimulate fibroblasts
haematopoiesis develops in the liver + spleen
myelofibrosis features
elderly person with sx of anaemia - fatigue
massive splenomegaly
hypermetabolic sx - weight loss, night sweats etc
myelofibrosis lab findings
anaemia
high WBC + platelets count
tear-drop poikilocytes on blood film
high urate + LDH –> reflect increased cell turnover
myelofibrosis bone marrow biopsy
unobtainable !!
- “dry tap” on biopsy
–> therefor trephine biopsy needed
essential thrombocytosis pathophys
megakaryocyte proliferation results in overproduction of platelets
features of essential thrombocytosis
platelets count >600
both THROMBOSIS and HAEMORRHAGE can be seen
characteristic sx = burning sensation in hands
what mutation is found in 50% of patients with essentia l thrombocytosis
JAK2 !
management of essential thrombocytosis
hydroxyurea (hydroxycarbamide) - to reduce platelet count
interferon-alpha - in younger patients
low dose aspirin - to reduce thrombotic risk
secondary causes of polycythaemia
COPD
altitude
obstructive sleep apnoea
excessive erythropoietin haemangioma
(dehydration = relative cause)
polycythaemia pathophys
clonal proliferation of marrow stem cell leading to increase in RED CELL VOLUME, often accompanied by overproduct of neutrophils + platelets
- incidence peaks in 6th decade
key genetic marker in polycythaemia
JAK2 !!!!!
- present in 95%
features of polycythaemia
pruritus -> esp after hot bath
splenomegaly
hypertension
hyperviscosity
- arterial thrombosis
- venous thrombosis
haemorrhage - 2nd to abnormal platelet
low ESR
polycythaemia investigations
FBC / blood film
- raised haemato crit
JAK2 mutation
serum ferritin
renal + liver function test
low ESR
management of polycythaemia
venesection = 1st line tx
aspirin - reduce thrombotic events
chemo
- hydroxyurea - slight increase risk of 2nd leukaemia
prognosis of polycythaemia
thrombotic events = big cause of morbidity+ mortality
5-15% progress to myelofibrosis
5-15% progress to acute leukaemia
- risk increased with chemo tx
“ruddy” complexion
polycythaemia
earliest finding in myelofibrosis
neutropaenia, without anaemia or thrombocytopenia
- spleen can compensate for red blood cell and platelet production in early disease –> massive splenomegaly
