Aplastic Anaemia + Polycythaemia Flashcards
How common is Aplastic anaemia
Rare
Defining features of aplastic anaemia
- Pancocytopenia (reduction in all major cell lines, RBC, WBC and platelets)
- Hypocellularity (aplasia of bone marrow)
Main causes of aplastic
- Inherited
- Idiopathic acquired (67%)
- Benzene, toluene, glue sniffing
- Chemotherapeutic drugs
- Antibiotics
- Infections
Pathophysiology of Aplastic anaemia
- Reduction in pluripotent stem cells together with a fault in those remaining or an immune reaction against them so they are unable to repopulate bone marrow
Clinical presentation of aplastic anaemia
- Anaemia
- Increased susceptibility to infection
- Bleeding
- Bleeding gums, bruising with minimal trauma and blood blisters in the mouth
What can aplastic anaemia be mistaken for
NHL
Myeloma
Blood count in aplastic
Pancocytopenia + low reticulocyte count
Bone marrow examination aplastic
Hypocellular marrow + increased fat spaces
How is aplastic treated
- Antibiotics urgently to prevent infections
- Red cell and platelet transfusion
- Bone marrow transplant
Describe immunosuppressive therapy after bone marrow transplant for aplastic anaemia
- ANTHITHYMOCYTE GLOBULIN and CICLOSPORIN
in over 40 or below 40 with severe disease + no HLA identical donor
What is polycythaemia
Increase in Hb, haematocrit and red cell count (all conc.)
Why is PCV a more reliable indicator of polycthaemia than Hb
Disproportionally low in iron deficiency
What can Polycythaemia be divided into
ABSOLUTE (increase in RBC mass) +RELATIVE (decreased plasma vol + normal RBC mass)
What is PRIMARY ABSOLUTE POLYCYTHAEMIA
- P. VERA
MUTATIONS IN ERYTHROPOIETIN RECEPTOR
HIGH OXYGEN AFFINITY Hbs
What is SECONDARY ABSOLUTE POLYCYTHAEMIA
- Hypoxia
2. High erythropoietin secretion
What is APPARENT POLYCYTHAEMIA
Chronic form associated with obesity, hypertension + high alcohol and tobacco intake
How is Polycythaemia Vera caused
Acquired mutations of gene JAK2
How is Polycythaemia vera caused genetically
- Point Mutation that causes the substitution of phenylalanine for valine at position 617
Role of JAK2
Cytoplasmic tyrosine kinase that induces signals, especially those triggered by haematopoietic growth factors such as erythropoietin
What age group does polycythaemia vera effect
Over 60
Pathophysiology caused by mutation of JAK2
- A clonal stem disorder resulting in a malignant proliferation of a clone derived from one pluripotent marrow stem cell
What is polycythemia vera
Bone marrow makes too many RBCs, WBCs and platelts
How does PV effect the bloodviscocity
Thicker as RBC population is larger
Do erythroid progenitor offspring need erythropoietin to avoid apoptosis
No
