Pancytopenia Flashcards
what is pancytopenia
a deficiency of blood cells of ALL lineages (however generally excluded lymphocytes)
what is the lifespan of red cells, neutrophils and platelets
red cells - 120 days
neutrophils 7-8 hours
platelets 7-10 days
causes of pancytopenia
reduced production (bone marrow problems)
increased destruction
causes of reduced production pancytopenia
Bone marrow failure
- inherited
- acquired (primary or secondary)
characteristics of inherited marrow failure syndromes
v rare
Fanconi’s Anaemia
- short stature
- skeletal abnormalities
- skin pigment abnormalities
- radial ray abnormalities
- hypogenetalia
- endocrinopathies
- GI defects
- cardiovascular defects
- renal defects
- haematological defects
what haematological abnormalities are seen in Fanconi’s Anaemia
unable to correct DNA damage
Macrocytosis followed by thrombocytopenia then neutropenia
84% risk of bone marrow failure by age 20
leukaemia risk 52% by age 40
median age 7 years
Types of acquired bone marrow failure
Primary - an intrinsic marrow problem
Secondary
Causes of primary acquired bone marrow failure
Idiopathic aplastic anaemia
-autoimmune attack against haemopoietic stem cells
Myelodysplastic syndromes
Acute leukaemia
-white cell count can be variable
what happens in idiopathic aplastic anaemia
auto-reactive T cells target haemopoeitic stem cells and myeloid progenitors
stops the production of myeloid cells
- erythroblasts
- platelets
- granulocytes
what are myelodysplastic syndromes
Hypercellular marrow with disordered development
increased apoptosis of progenitor and mature cells (ineffective haemopoiesis)
can become acute myeloid leukaemia
how can acute leukaemia cause pancytopenia
proliferation of abnormal blast cells from leukaemic stem cells
failure to differentiate into mature of normal cells
therefore there is a lack of normal mature cells but lots of abnormal blasts
causes of secondary bone marrow failure
drug induced (chemotherapy, chloramphenicol, alcohol)
B12/folate deficiency (nuclear maturation can affect all lineages)
non-haemopoieotic malignant infiltration
miscellaneous (viral, storage disease)
Causes of increased destruction pancytopenia
hypersplenism
- increased splenic pool
- increased destruction that exceeds bone marrow capacity, usually associated with significantly enlarged spleen
what is the splenic pool of a normal spleen
red cell mass 5%
red cell transit fast
splenic platelet pool 20-40%
what is the splenic pool in hypersplenism
red cell mass 40%
red cell transit slow
splenic platelet pool 90%
