Topic 4: Aplastic Anemia

Question 1

when does aplastic anemia occur?

Answer 1

occurs when the bone marrow and residing hematopoietic stem cells (HSCs) are damaged

this results in pancytopenia, or a deficiency in all three blood cell type

Question 2

how do you make a definitive diagnosis of aplastic anemia?

Answer 2

bone marrow biopsy has to be done

in aplastic anemia biopsy, there’s so much more white space because there’s less cells to stain

biopsy will show fatty, hypo cellular marrow

Question 3

what causes aplastic anemia?

Answer 3

HSC damage

the cause of the damage is unknown…some people think it’s autoimmune disturbances but there’s no known cause

some causes do have a known cause like exposure to chemicals of hereditary conditions:

1. radiation therapy & chemo: damage cancer cells but also HSC in the bone marrow
2. certain medications: cause reversible aplastic anemia
3. viral infections: parvovirus B19, epstein-Barr virus, HIV, HepB, HepC
4. toxic chemicals: benzene and insecticides
5. hereditary conditions: Fanconi anemia

Question 4

what medications cause reversible aplastic anemia?

Answer 4

chloramphenicol and carbamazepine

Question 5

what viral infections cause aplastic anemia?

Answer 5

parvovirus B19
Epstein-Barr virus
HIV
hepatitis B
hepatitis C

Question 6

what is Fanconi anemia?

Answer 6

defect in DNA repair mechanisms leads to bone marrow failure and increased risk of leukemia

hereditary form of aplastic anemia

autosomal recessive

Question 7

what are the clinical presentations of Fanconi anemia?

Answer 7

short stature

café-au-lait spots

radial/thumb defects

Question 8

what is pancytopenia?

Answer 8

when a person has low counts for all three types of blood cells: red blood cells, white blood cells, and platelets

Question 9

what are the clinical presentations of aplastic anemia?

Answer 9

they’re all a direct consequence of pancytopenia

anemia = fatigue and dyspnea

thrombocytopenia = petechiae and easy bruising

leukopenia = increased incidence of infections

Question 10

how do you treat aplastic anemia?

Answer 10

first, eliminate offending agent aka get rid of causative medications, exposure to chemicals, underlying infections

if no causative agent, then treat with immunosuppressive agent because sometimes AA is thought to be caused by aberrant T cell activation

bone marrow transplant to provide fresh HSCs as a last resort