anaemia Flashcards
The main stimulus for the production of RBCs in bone marrow is reduced delivery of O2 to the tissues. Which organ senses the reduced O2 level and stimulates the production of new RBCs?
kidneys
Each RBC contains 250 million Hb molecules. Therefore, how many O2 molecules can each RBC carry?
haem molecule carry 4 O2 so 1 billion
In addition to O2, what three other gases can Hb carry in the blood?
carbon dioxide
nitric oxide
carbon monoxide
How long do RBCs live and where do they go to die?
RBC circulate in the blood fro about 120days before being recycled by the spleen
if going off these values what would the RBC look like
Hb 100
• MCV 82
• MCHC 330
MCV 80-99
MCHC-320-360
normal values
Normocytic normochormic
if going off these values what would the RBC look like
Hb 100
• MCV 104
• MCHC 330
Macrocytic normochromic anaemia
if going off these values what would the RBC look like
Hb 100
• MCV 72
• MCHC 260
microcytic hypochromic anaemia
where is iron mainly absorbed in the small intestine
Enterocytes of duodenum and jejunum
Two forms of heme for absoprtion.
Which of the following is/are the non-heme iron?
Fe2+
Fe3+
Ferric ion
Ferrous ion
Fe3+= Ferric– non-heme
- Less well absorbed
Fe2+= Ferrous = binds to O2– heme
- Major form of iron more easily absorbed
Fe2+ or Fe3+ gets transported across the enterocyte brush boarder directly?
Fe^2+
Fe2+ soluble while Fe3+ isn’t
- Fe3+= FAT; Fe2+= slim
🡪 needs to get slimmer to squeeze through 🡪 Fe2+ is the one
Ferroreductase= duodenal cytochrome B is the enzyme that is required for the conversion
Iron is bound to what/ stored as what in the enterocytes? And what state is the iron in?
Ferritin; Fe3+
30% stored as ferritin in liver, bone marrow and spleen.
Iron study: Serum ferritin= best diagnostic test for iron deficinecy anaemia= measure of iron stores = ferritin= APP 🡪 changes in infection
Monomers of the ferritin molecule have ferroxidase activity (Fe3+ ↔ Fe2+) which allows the mobilization of Fe2+ ions out of the ferrihydrite mineral lattice structure, enabling its subsequent efflux out of the enterocyte via ferroportin, and into circulation across the basolateral membrane of the enterocyte.
What does iron bind to within circulation?
transferrin
Reason: Fe3+ is toxic as it is involved in the fenton reaction which generates free radical
Iron mobilisation to the circulation relies on transport protein transferrin
A beta 1 globulin . Transferrin of siderophilin
Iron travels to bone marrow to produce RBC
Or to Liver for storage
Transferrin as an indicator for TIBC- transferrin iron binding capacity -> iron study
chose the right words
When iron levels are excessively high, hepcidin levels increase/decrease.
Hepcidin binds to the transferrin/ ferroportin on basolateral surface of gut enterocytes and macrophages in spleen, stopping iron transport out of the cells.
increase and ferroportin
Regulators of iron: hepcidin levels.
High levels of iron, inflammatory cytokines, and oxygen lead to increased levels of the peptide hormone hepcidin.
Hepcidin binds ferroportin, resulting in its internalization and degradation and effectively shunting cellular iron into ferritin stores and preventing its absorption into the blood.
Iron recycling within the macrophages in spleen when rbc reach the end of their lifespan 🡪 iron is realeased from heme
Thereby, hepcidin also potentiates the excretion of iron through the sloughing of enterocytes (and their ferritin stores) into the feces and out of the body.
Clinical relevance:
- EPO reduction 🡪 Increased hepcidin activity is partially responsible for reduced iron availability seen in anemia of chronic inflammation, such as kidney failure.[10]
How is iron lost from the body?
Sloughing of enterocytes
Faeces
Menstruation
if HB of 66
MCV of 58.6
MCHC of 230
what anaemia
severe microcytic hypothermic anaemia - iron deficiency anaemia
ferritin would confirm this
if HB was 70
MCV - 105
MCHC was 315
what anaemia
microcytic normochromic anaemia
So B12 or folate deficiency anaemia
If microcytic – Probably iron deficiency commonest
(check ferritin)
If macrocytic – B12/folate commonest
(check B12 and Folate levels)
RBC fact slide
Major function:
To transport haemoglobin (Hb),which carries O2 from the lungs to the tissues
Also:
Contain carbonic anhydrase, which speeds up the reversible reaction between CO2 and H2O, to allow the water in the blood to carry large amounts of CO2, in the form of bicarbonate (HCO3), from the tissues to the lungs
Due to the Hb they contain, RBCs are also responsible for most of the acid-base buffering power of the blood
Haematocrit (HCT) or Packed Cell Volume represents the percentage of RBCs in the total blood volume. What is the normal value of haematocrit ?
36-49%
Which of the following cells within gastric pits release intrinsic factor?
Chief cells
Parietal cells
D cells
G cells
Chief cells – release pepsinogen (a zymogen = inactive precursor of an enzyme; most digestive enzymes are released as zymogens and then activated within the GI tract lumen by proteolytic cleavage by other enzymes or, in the case of pepsin, by HCl-mediate hydrolysis.
Parietal cells - HCl and Intrinsic Factor
D cells – release somatostatin hormone, a negative regulator of gastric acid release and gastric motility.
G cells – release gastrin hormone, a promoter of gastric acid release and gastric motility.
3 main groups of anaemias
Anaemia caused by blood loss
Heavy menstruation
Gastrointestinal conditions like ulcers or haemorrhoids and cancers.
Anaemia caused by decreased or faulty red blood cell production
Bone marrow and stem cell problems
Iron deficiency anaemia
Sickle cell anaemia
Anaemia caused by destruction of red blood cells
Aplastic anaemia
Lead poisoning
what would be the findings in the blood test for iron deficiency anaemia
Hb normal at start then fall MCV( average size) decrease MCHC( Hb in RBC decrease) Increased variation in the size of RBC (RDW) Low ferritin levels expected
To confirm that someone has Iron deficiency anaemia:
A blood film may show RBC that are smaller and paler then normal
Serum Iron (Iron level in blood) is usually decreased
Total Iron binding capacity will be increased (more proteins available to carry Iron)
Transferrin saturation index will be low
Ferritin levels will be low (key one)
(unusual) a marrow aspirate test
To confirm that someone has anaemia due to chronic disease: what would you do
Reticulocyte count
Tests for inflammation (ESR or CRP)
Kidney function tests such as serum creatinine
Erythropoietin
How would a blood test look for Vitamin B deficiencies
low Hb
High MCV
abnormally larger or and abnormally shaped RBC
Tests for haemoglobin variants DNA analysis (not routinely done) G6PD enzyme test Osmotic fragility test Test for autoantibodies Reticulocyte count
confirmation of what anaemia
Haemolytic anaemia:
Vitamin B12 levels will be low in B12 deficiency
Folic acid levels may be low
Mehylmalonic acid may be high with vitamin B deficiency
Homocysteine may be high with either folate or vitamin B deficiency
Reticulocyte count is usually low
Antibodies to intrinsic factor or parietal cell antibodies may be present in pernicious anaemia.
Bone marrow aspiration may be performed
confirmation of what anaemia
Vit B 12 déficiences
normal folate range
> 5.4ng/ml
iron deficiency anaemia is defined as what
low ferritin <30micrograms/litre , low iron and High total iron binding capacity , high transferring and low iron saturation
why should vitamin C be given in anaemia
vitamin c helps the body absorb iron
