Thalassaemia, Sickle Cell and Anaemia

Question 1

HbA=
HbF=
HbA2=

Answer 1

HbA= a2b2 adult Hb
HbF= a2y2 fetal Hb (switch at 3-4 months)
HbA2= a2d2, 2% of adult Hb

Question 2

type of anaemia produced by thalassaemia

Answer 2

microcytic hypochromic

Question 3

how to differentiate between iron deficiency and thalassaemia anemia

Answer 3

IRON: pencil cells, more anisocytosis and anisopoikilocytosis. elevated RDW. reduced RCC
THALASSAEMIA BETA MINOR: RDW normal, RCC normal, minor elevation of HbA2.

Question 4

what is RDW?

Answer 4

indicates variability of size and shape of rbcs

Question 5

raised HbA2 in presence of hypochromic microcytic anemia would indicate

Answer 5

beta thalassaemia minor

Question 6

what is alpha thalassaemia major? what Hb is present?

Answer 6

lost all the alpha genes.

presence of y4 Hb Barts. leads to Barts hydrops fetalis

Question 7

what is HbH

Answer 7

4 beta chains present in alpha thalassaemia

Question 8

type of anemia caused by alpha thalassaemia minor

Answer 8

microcytic hypochromic

Question 9

how do we diagnose alpha thalassaemia minor

Answer 9

its hard because HbH and Barts are often not elevated to detectable levels

Question 10

where is sickle cell most prevalent?

Answer 10

subsaharan africa eg. nigeria. should screen for sickle cell

Question 11

what happens to sickle cells as they pass through the microcirculation

Answer 11

they sickle up, become less deformable, increase blood viscosity and can affect oxygen deliver to brain kidneys luigns spleen. can get infarctions.

Question 12

cause of chest syndrome in sickle cell

Answer 12

necrosis of lung parenchyma

Question 13

cause of renal infarction in sickle cell

Answer 13

sickle cells get lodged at the bottom of loop of henle where oxygen is lowest

Question 14

consequences of neonatal sickle cell disease

Answer 14

initially protected due to HbF but then get abnormal growth and bone developemnt, more vulnerable to viruses

Question 15

treatment of sickle cell

Answer 15

• raise HbF (hydroxyurea, butyrates)
• reduce HbS
• transfusion (iron overload? need chelator therapy)
• manage complications

Question 16

why do we check for sickle cell before general anaesthesia

Answer 16

grave consequences, very bad.

Question 17

problems with regular transfusions for sickle cell patients

Answer 17

iron overload requiring chelator therapy

can make antibodies against other rare blood groups making blood matching very difficult

Question 18

what is anisocytosis

Answer 18

variable size of rbcs

Question 19

what is anisopoikilocytosis

Answer 19

variable size and shape of rbcs

Question 20

3 mechanisms of anemia

Answer 20

• loss
• impaired production
• increased destruction

Question 21

what is transferrin

Answer 21

transports iron around the body, absorbs iron

Question 22

what is ferritin

Answer 22

a storage protein of iron

also an acute phase protein

Question 23

what is hepcidin

Answer 23

regulator of iron metabolism. regulates circulating iron, iron availble for utilisation by bone marrow

Question 24

causes of excess iron

Answer 24

intake
transfusions
inherited conditions (hemochromatosis)

Question 25

side effects of iron replacement therapy

Answer 25

tarry stool nausea loss of appetitie

Question 26

what is anaemia of chronic disease? | what type of anemia does it cause?

Answer 26

inflammatory environment increases the amount of hepcidin, this reduces the amount of iron available for utilisation by the bone marrow causing normocytic or microcytic anemia

Question 27

findings on iron deficiency anemia of ferritin and transferring?

Answer 27

low ferritin | elevated transferrin

Question 28

findings on chronic disease anemia of transferrin and ferritin

Answer 28

ferritin is normal | transferrin is low

Question 29

5 findings of hemolytic anemia

Answer 29

- elevated lactate dehydrogenase - low haptoglobin - reticulocytosis - change in rbc morphology - unconjugated hyperbilirubinemia

Question 30

3 patterns of red cell morpholgy in haemolysis

Answer 30

- spherocytosis (hereditary or warm immune hemolysis) - microangiopathy (fragmented red blood cell aka schistocyte) - oxidative (bite cells and blister cells)

Question 31

what pattern of morphology does G6PD produce in rbcs

Answer 31

oxidative with bite and blister cells

Question 32

how can we test if anemia is immune mediated?

Answer 32

direct coombs test to find anti-red cell antibody bound to rbcs

Question 33

what is a reticulocyte

Answer 33

cell before erythrocyte, have nucleic acid but no nucleus

Question 34

what is microangiopahty

Answer 34

fragmented red blood cells on film, schistocytes etc

Question 35

what is aplastic anemia | how do you differentiate from hemolytic?

Answer 35

marrow has stopped making rbcs, | hemolytic will have reticulocytosis

Question 36

what causes macrocytic anemia

Answer 36

folate or B12 deficiency

Question 37

what is pernicious anemia

Answer 37

autoimmune reactoin against parietal cells in the stomach leading to a loss of intrinsic factor which prevents vitamin B12 absorption, leading to anemia