iron deficiency and anaemia of chronic disease

Question 1

what is the main store of iron *

Answer 1

Hb

Question 2

why could a pt feel tired from Fe deficiency but not be anaemic *

Answer 2

there are many protein stores of Fe and it could be that te pt is fe deficient but it has not affected Hb yet

Question 3

describe teh role of Fe in Hb *

Answer 3

it holds onto the oxygen - low Fe = low Hb = anaemia

Question 4

describe ow the structure of haemoglobin encorporates Fe *

Answer 4

Fe encorportaed into haem which sits in fold of globin chain

Question 5

what is the lifespan for red cells *

Answer 5

120 days

Question 6

what is the implication on Fe uptake of red cell lifespan *

Answer 6

to remake huge number of red cells everyday you need 20mg fe/day

but fe is recycles - fe from haemolysis can be reused in new red cells

however Fe also in skin and gut - iron from these stores is lost

also loss in menstruation

therfore men need 1mg fe/day

women need 2mg fe/day

human diet provides 12-15mg Fe/day

Question 7

where is fe in the diet *

Answer 7

meat and fish - absorbed in haem group so protected and absorbed

veg

wole grain cereal

chocolate

Question 8

what factors affect absorption of fe *

Answer 8

has to be absorbed in ferrous (Fe2+) form, not ferric (Fe3+) - factors influence this:

diet - increase in haem iron (meat), orange juice converts iron to 2+

intestine - acid increases absorption (duodenum), ligand (meat)

systemic - iron deficiency (absorb more Fe), anaemia/hypoxia, pregnancy

Question 9

describe the absorption of Fe *

Answer 9

absorbed into the SI cell from the lumen

then absorbed into the plasma

ferroportin is needed for absorption into the plasma

Question 10

what is ferritin *

Answer 10

an iron store

Question 11

describe ow Fe absorption can be regulated by fe levels *

Answer 11

high iron = high hepcidin (inibits ferroportin) = low ferroportin = low Fe absorption

low fe (iron defiency) = low hepcidin = high ferroportin = high fe absorption

Question 12

what does transferrin do *

Answer 12

holds on to iron in circulation

Question 13

what are the different tests that can measure transferrin *

Answer 13

transferrin

total iron binding capacity

transferrin saturation (same as above) - 20-50% transferrin saturated normal

Question 14

describe the bodies response to anemia regarding erythropoeitin and how this includes Fe *

Answer 14

anemia/tissue hypoxia = increase in erythropoeitin = increase in red cell precursers which survive longer, grow and differentiate

fe is what holds onto the oxygen in hb and so reduces the hypoxia

Question 15

what is anaemia of chronic disease *

Answer 15

anaemia in patients that are ill

no obvious cause other than the fact they are unwell

Question 16

what are conditions associated with anaemia of chronic disease *

Answer 16

chronic infection eg TB/HIV

chronic inflammation eg rheumatoid athritis, lupus

malignancy

miscellaneous eg cardiac failure

Question 17

what are the lab signs of being unwell *

Answer 17

C reactive protein raiseed in inflammation or infection

erythrocyte sedimentation rate - up non specifically when unwell

acute phase response- acute phae proteins increase - ferritin, FVIII, fibrinogen, immunoglobulins

Question 18

how do cytokines contribute to ACD *

Answer 18

cytokines released - prevent usual flow of iron from duodenum to red cells - therefore block iron utilisation

they stop erythropoeitin increasing when anaemic - make less red cells

stop iron flow out of cells

increase production of ferritin - less available iron

increase death of red cells

Question 19

examples of cytokines that cause ACD *

Answer 19

TNF alpha

interleukins

Question 20

what are causes of fe deficiency *

Answer 20

• mainly bleeding - menstrual or GI - could be innocuous eg piles/gastritis but could be cancer/polyps

increased use - increased growth/pregnancy in pregnancy there is increased absorption but the baby takes it preferentially

malabsorption eg coeliac

Question 21

what investigations would you do into the cause of iron deficiency *

Answer 21

full gi investigation if - male, women over 40, post menopausal women, women with scanty menstural loss

if women <40 with heavy periods or multiple pregnancies and no GI symptoms - do nothing

if women has stopped periods but is iron def could havae uterine or fibroid cancer that is bleeding very slowly so she doesnt notice - make her iron def

urinary blood loss - from renal cancer

Ab for coeliac disease

Question 22

what is a full GI investigation *

Answer 22

upper Gi endoscopy - oesophagus, stomach, duodenum

take duodenal biopsy

colonoscopy - colon and maybe bottom of SI

small bowel meal and follow throug if found nothing from end/colonoscopy - swallow camera that photographs bowel

check for PR bleeding, malaena (sticky faeces with blood in it), haematemesis (vomiting blood)

Question 23

what are the haematological features of IDA *

Answer 23

low MCV

low Hb - anaemia

low serum iron

low ferritin (however if also have chronic disease - which raises ferritin levels, ferritin can be normal with Fe deficiency - determine this by seeing if other acute phase proteins are raised eg CRP and ESR)

transferrin high

low transferrin saturation - transferrin high and fe low

Question 24

what investigation do you do when you know someone is iron deficient *

Answer 24

1st - anti-coeliac ab

endoscopy and colonoscopy

duodenal biopsy

anti-helicobacter ab

abdo ultrasound to look at kidneys

dipstick urine

pelvic ultrasound to exclude fibroids

Question 25

what are potential pitfalls for haematological features being used for diagnosis *

Answer 25

some measurements migt show ida and some migt show ACD

Question 26

what are the haematological signs of ACD *

Answer 26

low Hb

low or normal MCV

low serum iron - dont have normal iron flow

high or normal ferritin - acute phase protein

normal or low transferrin - dont make proteins as well because ill

normal transferrin saturation - can be normal if both transferrin and iron go down

Question 27

what are the 3 causes of low MCV *

Answer 27

iron deficiency

thalassaemia trait

anaemia of chronic disease (low or normal)

Question 28

haematological signs of thalassaemia trait *

Answer 28

Hb low

mcv - low

serum iron - normal

ferritin - normal

transferrin - normal

transferrin saturation - normal

Question 29

how would you confirm thalassamia trait *

Answer 29

hb electrophoresis

confirms an additional type of Hb is present - raised HbA2 with B thalassamia

Question 30

what is the blood stain for iron deficiency *

Answer 30

cells pale

variation in sape

pencil cells

definitely red cell because red around edge and central pallor

Question 31

what are the haematological signs of rheumatoid artritis and bleeding ulcer *

Answer 31

hb low

mcv - low

serum iron - low

ferritin - normal (because mix of ACD and IDA - ACD increases it, IDA decreases it)

transferrin saturation - low

Question 32

what additional tests would you do if didnt know if IDA/thal/ACD *

Answer 32

blood film

bone marrow - stain for iron

Question 33

clinical features of iron deficient anaemia *

Answer 33

fatgue

pale skin

palpitations

shortness of breath

Question 34

how do you manage iron deficient anaemia *

Answer 34

oral iron compounds - most commonly ferrous sulphate

SE - constipation, indigestion

compounds containing less iron are better tolerated: ferrous fumarate or ferrous gluconate

can be given parenterally IM or IV

Question 35

why do you get ankle swelling in anaemia

Answer 35

there is an increased co

Question 36

how can corticosteroids anad aspirin cause IDA *

Answer 36

they can cause peptic ulceration

Question 37

causes of thrombo and leukocytosis *

Answer 37

increase in inflammation

iron deficiency can cause thrombocytosis

Question 38

how can erythrocyte sedimentation rate indicate inflammation *

Answer 38

normally - negative carges on red cell mean tey dont stick together

if have inflammatory proteins - they cancel out the -ve charge so red cells stack = higher esr