thrombocytopenia Flashcards
1
Q
four main processes leading to a reduced platelet count
A
- failure of marrow production
- shortened lifespan
- sequestration
- dilution
2
Q
failure of marrow production examples + notes
A
- aplastic anaemia
- megaloblastic anaemia
- leukaemia
- causes pancytopenia
3
Q
shortened lifespan examples + notes
A
- ITP
- DIC
- connective tissue disorders
- usually destroyed within circulation by immune system attack
4
Q
sequestration
A
- cardiopulmonary bypass surgery
- platelets pool in spleen
5
Q
dilution
A
massive blood transfusion
6
Q
autoimmune thrombocytopenia (ITP)
A
- immune cells drestroy platelets
- antibody produced that’s directed to platelet antigens
- low platelet count
- red/purple rash
- increased tendency to bleed
7
Q
ITP can arise from…
A
- isolated disease
- feature of autoimmune disease
- complication of chronic lymphocytic leukaemia
8
Q
ITP most common in …
A
young female adults
9
Q
acute ITP
A
- usually seen in childhood
- post viral IgG antiboes attach to viral antigen that are absorbed into the platelet surgace
- platelet levels fall to 20x10^9/L
- self limiting
- if not, oral steroids or IV immunoglobulins used
- very few progress to chronic; benign
10
Q
chronic ITP
A
- more likely in adulthood
- antibody destruction of platelets
- damage megakaryocytes
- asymptomatic
- fatigue
11
Q
thrombotic thrombocytopenic purpura (TTP)
A
- platelets aggregate sin small vessels causing petechial rash
- fever
- fluctuating neurological symptoms
- haemolytic anaemia
- renal impairement
- due to deficiency of vWF cleaving protease
- ultra large vWF molecules trap platelets onto endothelial surfaces
