anaemia Flashcards
(24 cards)
where does iron absorption primarily occur
duodenum and upper jejunum
what is the action of hepcidin
reduces the levels of iron in the plasma by binding ferroportin and degrading it
how are RBCs described in IDA
microcytic and hypochromic
give three causes of IDA
- Dietary
- premature neonates
- adolescent females - Malabsorption
- E.g. Coeliac disease - Blood loss
which iron replacements would you give a person with IDA
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
what sort of anaemia does a B12/folate deficiency cause
megaloblastic (presents as a macrocytosis)
where does B12 absorption predominately occur
terminal ileum
which tissues may be affected by B12/folate deficiency ?
- All are rapidly growing, DNA synthesising cells
- Bone marrow
- Epithelial surfaces e.g. mouth, stomach, small intestine, urinary, female GU
which haemoglobin do you have as an adult
A
what is a thalassaemia
an inherited blood disorder in which there is a relative lack of globin genes
how many globin genes does a normal person have
4 alpha globin genes
2 beta globin genes
what is HbH
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.
why is alpha thal major incompatible with life?
absence of alpha chains.
Alpha chains are required for foetal haemoglobin
in beta thalassaemia major what compliactions might you see
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
how are people with beta thalassaemia treated
blood transfusions and iron chelation
what is the pathogenesis of sickle cell anaemia
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.
name some complications of sickle cell
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
how is sickle cell treated
- 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
name 2 congenital types of haemolytic anaemia
hereditary spherocytosis, sickle-cell
what are the two types of acquired haemolytic anaemia that are auto-immune?
warm type: IgG
cold type: IgM
what are the thee ways a drug can cause AIHA
hapten, immune complex (innocent bystander), auto-immune
what are the two types of auto-immune haemolytic anaemia
warm - IgG: RBCs are mainly destroyed via phagocytosis
cold - IgM. RBCs mainly destroyed by complement
which test is used to identify AIHA
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:
what is an indirect coomb’s test used for?
screening of blood prior to transfusion and detecting blood group antibodies in pregnant women
