Pure Red Cell Aplasia

Question 1

Pure red cell aplasia (PRCA): definition

Answer 1

Acquired syndrome characterized by severe anemia, lack of reticulocytosis, and absence of erythroid precursors in bone marrow - leukocyte and platelet production are not affected

Question 2

Classifications of PRCA:

Answer 2

Idiopathic: Secondary: - parvo B19 - thymoma - collagen vascular or autoimmune diseases - lymphoproliferative disorders - other bone marrow disorders - solid tumors - anti-EPO ab after treatment with exogenous EPO - other drugs (ex: phenytoin, chloramphenicol, isoniazid) - Pregnancy - ABO-incompatible stem cell transplant

Question 3

Workup for PRCA:

Answer 3

• identifying new drugs or toxins - CT to exclude thymoma - flow cytometry of blood or bone marrow - parvo B19 testing (esp if pts develop severe acute hypoproliferative anemia) - HIV testing - serologies for autoimmune disorders - peripheral blood smear to r/o large granular lymphocytosis

Question 4

What is this diagnosis? How is this diagnosed? What is this associated with?

Answer 4

Large granular lymphocystosis: a lymphoproliferative syndrome characterized by large numbers of granular lymphocytes with abundant cytoplasm and azurophilic granules that infiltrate the bone marrow - seen on peripheral blood smear - common cause of secondary PRCA

Question 5

Diagnostic studies for large granular lymphocytosis: Signs/symptoms:

Answer 5

• flow cytometry with CD57-positive T cells and clonality on T-cell receptor gene arrangement studies are diagnostic - splenomegaly - 1/3 have rheumatic syndrome suggestive of rheumatoid arthritis - recurrent infections

Question 6

Signs/symptoms of PRCA:

Answer 6

Anemia - CBC normal except for isolated normocytic anemia - bone marrow shows lack of erythroblasts and an excess of precursor pronormoblasts - otherwise unremarkable

Question 7

Management of PRCA (first approach):

Answer 7

• erythrocyte transfusion for pts with symptomatic anemia - removal of offending drugs and/or treatment of underlying disease (ex: chemo for lymphoproliferative disorders) - if this doesn’t work, tx is immune-based

Question 8

Management of chronic primary PRCA:

Answer 8

• immune-based treatment - prednisone, antithymocyte globulin, cyclosporine A, cyclophosphamide = standard first-line agents - most pts respond within 3-12 weeks

Question 9

Treatment of PRCA 2/2 parvo B19:

Answer 9

• can use IVIG - although pts with normal immune function may recover spontaneously

Question 10

Treatment of PRCA 2/2 thymoma:

Answer 10

• consider surgical resection, however only a few pts respond to this approach

Question 11

% of idiopathic PRCA that resolves without therapy:

Answer 11

10%