Red Cell Aplasia Flashcards
What is pure red cell aplasia?
Isolated reduction in RBC production leading to normocytic normochromic anaemia. the entire red cell line is affected and maturation is arrested, other lineages are not affected so there is normal WBC count and macrocytes
What can occur in RCA which distinguishes it from haemolytic anaemia?
Reticulocytopeia
What are the congenital causes of pure red cell aplasia?
Diamond Blackfan anaemia
What are the acquired causes of pure red cell aplasia?
Immune disease
Virus
Pregnancy
Drugs
What are the immune disease associated with PRCA?
Thymoma - 5-10% develop PRCA, thymectomy only cures 30%
Autoimmune disease
Lymphoproliferative disease - t granular lymphocyte leukaemia
What are the viral causes of PRCA?
Parvovirus B19
HIV
Hepatitis
EBV
What drugs are related to PRCA?
Antiepileptics azathiaprine chloramphenicol sulphonamides hydroxycarbamide EPO
What is the pathophysiology of the immune related PRCA?
Antibody mediated with serum inhibitors against red cells
What is the effect of parvovirus 19?
This is a DNA virus and enters the CFU-E (erythroid progenitor) cells via P antigen P antigen is a cellular receptor for erythroid cells, megakaryocytes, endothelial cells, placenta and fetal lvier and heart.
Direct cytotoxicity leads to erythropoietic arrest
Giant proerythroblasts on marrow aspirate.
What are the haematological syndromes that occur with parvovirus b19?
- transient aplastic crisis - sudden onset anaemia may be life threatening
- pure red cell aplasia - chronic anaemia occuring in immunocompromised patients
- hydrops fetalis - pantigen is on the placenta
- congenital infection - p antigen on the heart, liver and megakaryocytes
What is the cell mediated pathophysiology of RCA?
There is directed killing by lymphocytes and white cells
