Pancytopenia and bone marrow failure Flashcards
What is responsible for haematopoiesis?
Bone marrow
Describe how some anaemias such as thalassaemia result in Organomegaly
Increased demand induces haematopoiesis outside of the bone marrow (extramedullary) in the liver and spleen
What is pancytopenia?
Reduction in all the major cell lines: red cells, white cells, platelets
What causes pancytopenia
Decreased marrow production - aplastic anaemia, infiltration, megaloblastic anaemia and myelofibrosis
Increased peripheral destruction - hypersplenism
What is agranulocytosis
Impaired production of granulocytes (WBC with neutrophil, basophil and eosinophil granules)
What is the major risk of agranulocytosis
Increased infection susceptibility
What drugs can cause agranulocytosis
Sulphonamides such as dapsone Gold Clozapine Carbimazole Procainamide
What must you tell patients before starting drugs known to cause agranulocytosis?
Warn them to report any fevers
What do you do to manage agranulocytosis
Stop causative drug
Commence neutropenic regimen
Consider G-CSF if indicated
Considering cell survival, what are the earliest signs of bone marrow failure
Neutropenia and Thrombocytopenia
How much should IU of red cells raise the Hb by?
10-15g/L
What might happen to the platelets when a transfusion is given?
Platelets will drop
When should platelets be given when giving a red cell transfusion?
Before or after
What symptoms occur when platelets are below 50X10^9/L
Traumatic bleeds, purpura, easy bruising
What symptoms occur when platelets are below 20X10^9/L
Spontaneous bleeding - rarely intracranial haemorrhage
At what temperature are platelets stored at?
22 degrees - room temp
When might platelets need to be irradiated?
In marrow transplant/severely immunosuppressed - to prevent transfusion associated GVHD
When are platelets indicated
Platelets <10X10^9/L
Haemorrhage
Before invasive procedures - biopsy, lumbar puncture - increase count >50X10^9/L - 4U may be needed but check with lab
What is the management for neutrophils <0.5X10^9/L
Neutropenic regimen
What must platelets be compatible with
ABO
Describe a bone marrow biopsy
Gives diagnostic information when there are abnormalities on peripheral blood
Important in staging
Take and aspirate and trephine from posterior iliac crest.
Aspirate provides a film
Trephine is a core of bone with allows assessment of cellularity, bone marrow architecture and the presence of infiltrative disease
What must be corrected prior to bone marrow biopsy?
Coagulation
What must be done after bone marrow biopsy
Apply pressure, lay on that side for 1-2 hrs if platelets are low
What is aplastic anaemia
Rare stem cell disorder where the bone marrow stops making cells - results in a pancytopenia
Give the classic presentation of aplastic anaemia and blood results
Decreased WCC - infection
Decreased platelets - bleeding
Decreased RBC - anaemia
What is the diagnostic test of aplastic anaemia
Bone marrow biopsy
How is aplastic anaemia treated?
Supportive in asymptomatic patients
Initiate neutropenic regimen if neutrophils <0.5X10^9/L
Young people with severe disease - allogenic bone marrow transplantation with a HLA-matched sibling
Immunosuppression with ciclosporin and antithymocyte globulin
No clear role for G-CSF
What causes aplastic anaemia
Autoimmune Drugs Infection - hepatitis and parvovirus Irradiation Inherited - fanconi anaemia
