Thalassaemia, Sickle Cell and Anaemia Flashcards Preview

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Flashcards in Thalassaemia, Sickle Cell and Anaemia Deck (37):
1

HbA=
HbF=
HbA2=

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

2

type of anaemia produced by thalassaemia

microcytic hypochromic

3

how to differentiate between iron deficiency and thalassaemia anemia

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

4

what is RDW?

indicates variability of size and shape of rbcs

5

raised HbA2 in presence of hypochromic microcytic anemia would indicate

beta thalassaemia minor

6

what is alpha thalassaemia major? what Hb is present?

lost all the alpha genes.
presence of y4 Hb Barts. leads to Barts hydrops fetalis

7

what is HbH

4 beta chains present in alpha thalassaemia

8

type of anemia caused by alpha thalassaemia minor

microcytic hypochromic

9

how do we diagnose alpha thalassaemia minor

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

10

where is sickle cell most prevalent?

subsaharan africa eg. nigeria. should screen for sickle cell

11

what happens to sickle cells as they pass through the microcirculation

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

12

cause of chest syndrome in sickle cell

necrosis of lung parenchyma

13

cause of renal infarction in sickle cell

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

14

consequences of neonatal sickle cell disease

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

15

treatment of sickle cell

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

16

why do we check for sickle cell before general anaesthesia

grave consequences, very bad.

17

problems with regular transfusions for sickle cell patients

iron overload requiring chelator therapy
can make antibodies against other rare blood groups making blood matching very difficult

18

what is anisocytosis

variable size of rbcs

19

what is anisopoikilocytosis

variable size and shape of rbcs

20

3 mechanisms of anemia

-loss
-impaired production
-increased destruction

21

what is transferrin

transports iron around the body, absorbs iron

22

what is ferritin

a storage protein of iron
also an acute phase protein

23

what is hepcidin

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

24

causes of excess iron

intake
transfusions
inherited conditions (hemochromatosis)

25

side effects of iron replacement therapy

tarry stool
nausea
loss of appetitie

26

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

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

27

findings on iron deficiency anemia of ferritin and transferring?

low ferritin
elevated transferrin

28

findings on chronic disease anemia of transferrin and ferritin

ferritin is normal
transferrin is low

29

5 findings of hemolytic anemia

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

30

3 patterns of red cell morpholgy in haemolysis

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

31

what pattern of morphology does G6PD produce in rbcs

oxidative with bite and blister cells

32

how can we test if anemia is immune mediated?

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

33

what is a reticulocyte

cell before erythrocyte, have nucleic acid but no nucleus

34

what is microangiopahty

fragmented red blood cells on film, schistocytes etc

35

what is aplastic anemia
how do you differentiate from hemolytic?

marrow has stopped making rbcs,
hemolytic will have reticulocytosis

36

what causes macrocytic anemia

folate or B12 deficiency

37

what is pernicious anemia

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