Anaemia and microcytic anaemias

Question 1

adult males normal HB

Answer 1

<130g/L

Question 2

adult females normal HB

Answer 2

<120g/L

Question 3

where does red cell rpoduction take place and how

Answer 3

bone marrow

severe eurythoid precursors cluster around a central nursing histiocyte

Question 4

how can hb be measured using a spectrophotometric method

Answer 4

burst red cell to create hb solution 
stabilise Hb molecules - cyanmetHb
measure optical density at 540nm
OD proportional to concern - beers law
Hb concentration calculated against known reference

Question 5

how to measure haematocrit

Answer 5

ratio of whole blood that is red cells if the sample was left to settle

Question 6

what is the response to anaemia

Answer 6

increase red cell production - reticulocytosis

Question 7

what are reituclocytes 
what do they still have remnants of
stain how 
blood film 
how long does up regulation take

Answer 7

red cells that have left the bone marrow, larger than av red cells

remnants of protein making machinery

stain purple/deeper red

blood film - polychromatic

up regulation of reticulocyte production by the bone marrow in response to anaemia takes a few days

Question 8

what can automated analysers say about red cells

Answer 8

physical - size, light scattering properties

rapid and reproducible

Question 9

what is measured and calculated in analysers

Answer 9

Hb conc
number of red cells
size of red cells - MCV

haemotacrit
mean cell hb
mean cell hb conc

Question 10

what other things can be looked for

Answer 10

blood film - cell morphology

reticulocyte count - assess marrow response

Question 11

pathophysiological classification of anaemia

Answer 11

decreased production

• hyperproliferative (low amount of erythro)
• maturation abnormality - erythro present but ineffective — cytoplasmic defects, nuclear defects

increased loss or destruction of red cells

• bleeding
• haemolysis

Question 12

low MCV

Answer 12

microcytic

problems with haemoglobinisation

Question 13

MCV high

Answer 13

macrocytic

problems with maturation

Question 14

where does hb synthesis occur and what do defects result in

Answer 14

cytoplasm

small cells that are hypo chromic (lacking in colour)

Question 15

what is needed to make hb

Answer 15

globes
haem - porphyrin ring, Fe 2+

shortages leads to small red cells w low Hb content

Question 16

hypo chromic microcytic anaemias

Answer 16

deficient haemoglobin synthesis : cytoplasmic defect

Question 17

causes of hypo chromic microcytic anaemias

Answer 17

haem deficiency

• lack of iron for erythropoiesis: iron defic, chronic disease so normal body iron but lack of available iron
• problems with porphyitin synthesis: lead poisoning, pyridoxine responsive anaemias
• congenital sideroblastic anaemia

global defic
-thalassaemia (trait, intermedia, major)

Question 18

how does iron exist

Answer 18

Fe2+

oxidised - Fe3+

Question 19

why is iron essential

Answer 19

oxygen transport

electron transport

Question 20

why does iron need to be handled safely by the body

Answer 20

potentially toxic as generates are radicals

Question 21

adult hb units

Answer 21

4 global sub units each w a haem molecule
haem group contains a single Fe2+ ion
each group can bind to one o2 molecule

Question 22

fully saturated 1g of hb

Answer 22

will bind 1.34ml of o2

Question 23

where is most of the iron in the body

Answer 23

in hb

Question 24

how much iron is absorbed

Answer 24

a small amount

Question 25

iron turnover

Answer 25

fast - 4mg in pool and move 20mg/day

Question 26

what is circulating iron bound to

Answer 26

transferrin

Question 27

where is circulating iron transferred to

Answer 27

to the bone marrow macrophages that feed it to red cell precursors

Question 28

where is iron stored

Answer 28

in ferritin mainly in the liver

Question 29

tests to assess iron status

Answer 29

function iron - hb
transported iron - serum, transferrin, transferrin saturation
storage iron - serum ferrratin

Question 30

what is transferrin

Answer 30

protein with two binding sites for iron atoms

Question 31

what does transferrin do

Answer 31

transports iron from donor tissues (macrophages, intestinal cells and hepatocytes) to tissues expressing transferrin receptors (esp erythroid marrow)

Question 32

what does percentage sat of transferrin with iron measure

when is it reduced/increased

Answer 32

measures iron supply

reduced in iron deficiency, in anaemia of chronic disease

increased in genetic haemachromatosis

Question 33

what is ferritin

Answer 33

large intracellular protein

Question 34

spherical protein stores what

Answer 34

up to 4000 ferric ions

tiny amount of ferritin present in serum - reflect intracellular ferritin synthesis in response to iron status in host

Question 35

serum ferritin measures what

Answer 35

indirect measure of storage iron

Question 36

low ferritin

Answer 36

iron deficiency

Question 37

how can iron defic be confirmed

Answer 37

comb of anaemia (low functional iron) and reduced storage iron (low serum iron )

Question 38

causes of iron defic

Answer 38

not eating sufficient to meet physiological requirements

• relative defic - preg
• absolute defic - vegetarian

losing blood
not absorbing enough - coeliac, achlorhydria

Question 39

causes of chronic blood loss

Answer 39

menorrhagia - commonest
GI - tumours, ulcers, NSAIDs
haematuria

Question 40

av menstrual blood loss
av daily intake
iron status
heavy menstrual blood loss

Answer 40

30-40ml/month = 15-20mg/month

daily intake 1mg/daily

status precarious

> 60ml i.e. >30mg/month

Question 41

sequence of neg iron balance

Answer 41

exhaustion of stores
iron deficient

erythropoiesis - falling red cell MCV

microcytic anaemia

epithelial changes - skin,, koilynychia

Question 42

occult blood loss

Answer 42

small volume GI blood loss can occur without any symp or signs of bleeding

this can outstrip max dietary iron absorption or iron and result in anaemia

iron supplements