Hematology Week 2: Failure of Bone Marrow Flashcards
Bone Marrow failure causes
Can be congenital or acquired
Constitutional Aplastic Anemia examples
4 listed
- Fanconi Anemia
- Shwachman-Diamon Syndrome
- Dyskeratosis congenita
- Diamond-Blackfan Syndrome (red-cell aplasia)
Acquired Bone Marrow Failure examples
2 listed
Idiopathic aplastic anemia
Paroxysmal nocturnal hemoglobinuria (PNH)
BM failure vs Aplastic Anemia
not equal terms
aplastic anemia is a form of BM failure
Criteria for Aplastic anemia
- Cytopenia
- Hypocellular Marrow
Cellularity to age
age 80 = 20% cellularity
Causes of Acquired Aplastic Anemia
6 listed
Idiopathic - majority of cases
Idiopathic aplastic anemia Etiology
- Immune-mediated process underlying idiopathic aplastic anemia pathogenesis
- oligoclonally expanded cytotoxic T cells induce apoptosis of hematopoietic progenitors (Tregs significantly reduced, increased Thelp cells) indicative of antigen driven process
- Suggestive HLA class-I drive autoimmunity in Aplastic Anemia
Idiopathic Aplastic Anemia clinical Features
4 listed
- Thrombocytopenia is a prominent feature
- Small PNH clone detected
- High TPO level
- Benefit from immunosuppressive therapy
Pancytopenia
- very empty
- not enough RBCs
- Not enough Platelets
- Not enough Neutrophils
Management of Aplastic Anemia
5 main
- need to rule out folate and B12 deficiency
- gastric bypass can resect where vitamins are absorbed
Treatment of Idiopathic Aplastic Anemia
HSCT is curative
Prognosis of Idiopathic Aplastic Anemia
50-80% 5 year survival
If a sibling is not available for HSCT then Idiopathic Aplastic Anemia is treated with?
Immunosuppressive Therapy
- Horse ATG
Horse ATG
in conjunction with prednisone and cyclosporine
Idiopathic Aplastic Anemia Horse ATG or
Idiopathic Aplastic Anemia can evolve into
MDS/AML
Idiopathic Aplastic Anemia Supportive Care
very open to infections and fungal infections so prophylactic bacterial and fungal medications
Drugs of Drug-induced Aplastic Anemia
Infection-induced Aplastic Anemia
4 listed
Parvovirus B19 is commonly associated with
- Megaloblastic anemia
- 5% will have aplastic anemia
Case study
erythroblasts with nuclear inclusions of Parvovirus B19
Parvovirus B19 stain
Parvovirus B19 can cause?
PNH AKA
Paroxysmal Nocturnal Hemoglobinuria (PNH)
PNH Etiology
4 listed
- Acquired disorder of HSC
- a defect in the phosphatidylinositol glycan complementation class A (PIGA) gene which leads to a defect in GPI synthesis
- GPI are membrane anchors for other proteins such as enzymes, receptors, complement regulators CD55 and CD59 and adhesion molecules
- When CD55 and CD59 are missing, complement activation will lead to MAC formation, thus intravascular hemolysis
GPI AKA
Glycophosphatidylinositol
PNH Treated with?
- Eculizumab
- the MAC will be blocked however C3 will accumulate and the RBCs will be preyed on by macrophages because of complement deposition
- before treatment Coombs test is negative but after treatment Coombs test is positive