anaemia

Question 1

where does iron absorption primarily occur

Answer 1

duodenum and upper jejunum

Question 2

what is the action of hepcidin

Answer 2

reduces the levels of iron in the plasma by binding ferroportin and degrading it

Question 3

how are RBCs described in IDA

Answer 3

microcytic and hypochromic

Question 4

give three causes of IDA

Answer 4

1. Dietary
   - premature neonates
   - adolescent females
2. Malabsorption
   - E.g. Coeliac disease
3. Blood loss

Question 5

which iron replacements would you give a person with IDA

Answer 5

ferrous sulphate or gluconate

Can give IV iron if there are issues with oral iron but it does not raise the Hb any quicker than oral iron

Question 6

what sort of anaemia does a B12/folate deficiency cause

Answer 6

megaloblastic (presents as a macrocytosis)

Question 7

where does B12 absorption predominately occur

Answer 7

terminal ileum

Question 8

which tissues may be affected by B12/folate deficiency ?

Answer 8

• All are rapidly growing, DNA synthesising cells
• Bone marrow
• Epithelial surfaces e.g. mouth, stomach, small intestine, urinary, female GU

Question 9

which haemoglobin do you have as an adult

Answer 9

A

Question 10

what is a thalassaemia

Answer 10

an inherited blood disorder in which there is a relative lack of globin genes

Question 11

how many globin genes does a normal person have

Answer 11

4 alpha globin genes

2 beta globin genes

Question 12

what is HbH

Answer 12

haemoglobin H disease
Only have one alpha gene so your beta globins combine with eachother and form HbH.
They often have a significant anaemia and bizzarre shaped small red cells.

Question 13

why is alpha thal major incompatible with life?

Answer 13

absence of alpha chains.

Alpha chains are required for foetal haemoglobin

Question 14

in beta thalassaemia major what compliactions might you see

Answer 14

dyserythropoiesis - body breaks down the faulty RBCs before they can leave the bone marrow
Splenomegaly - RES breaking down all these faulty RBCs.
formation of bony prominences as bone marrow is attempting to produce enough RBCs

Question 15

how are people with beta thalassaemia treated

Answer 15

blood transfusions and iron chelation

Question 16

what is the pathogenesis of sickle cell anaemia

Answer 16

single amino acid substitution on B globin gene.
Forms HbS which when deoxygenated undergoes polymerisation. Long polymers that result deform the RBC and make it sickle shaped.
If this process occurs repeatedly it damages and dehydrates the cell membrane making them irreversibly sickle shaped.
Causes reduced cell survival and vaso-occlusion.

Question 17

name some complications of sickle cell

Answer 17

moya moya - get constriction of arteies in the brain with subsequent formation of a collateral circulation around the blockages to compensate. Weak vessels are prone to rupture and so can lead to stroke
Lungs - acute chest syndrome, pulmonary hypertension.
Bones - dactylitis, osteonecrosis - thought due to stiff and abnormally adherent blood cell impairing blood flow to articular surfaces causing bone infarction
Spleen - hyposplenic
Kidneys - infarction
Eyes - vascular retinopathy

Question 18

how is sickle cell treated

Answer 18

• Prevent crises:
  o Hydration, analgesia, early intervention
  o Prophylactic vaccination and antibiotics
  o Folic acid
  o (patients who have had a splenectomy are at risk from encapsulated organisms.)
• Prompt management of crises
  o Oxygen, fluids, analgaesia, antibiotics, specialist care
  o Transfusion/red cell exchange
• Bone marrow transplant

Question 19

name 2 congenital types of haemolytic anaemia

Answer 19

hereditary spherocytosis, sickle-cell

Question 20

what are the two types of acquired haemolytic anaemia that are auto-immune?

Answer 20

warm type: IgG

cold type: IgM

Question 21

what are the thee ways a drug can cause AIHA

Answer 21

hapten, immune complex (innocent bystander), auto-immune

Question 22

what are the two types of auto-immune haemolytic anaemia

Answer 22

warm - IgG: RBCs are mainly destroyed via phagocytosis

cold - IgM. RBCs mainly destroyed by complement

Question 23

which test is used to identify AIHA

Answer 23

Direct
Direct: positive result will show agluttination of RBCs upon addition of anti-human globulin. This means it is either Haemolytic disease of the newborn or AIHA.
Indirect:

Question 24

what is an indirect coomb’s test used for?

Answer 24

screening of blood prior to transfusion and detecting blood group antibodies in pregnant women