Anaemias

Question 1

what is haematocrit

Answer 1

%RBC of blood volume

Question 2

in what scenarios is Hb not a good indicator of anaemia

Answer 2

if the patient has lost a large volume of blood

if the patient has been given saline fluids

Question 3

what are the 2 classifications of anaemia

Answer 3

microcytic

macrocytic

Question 4

what determines if an anaemia is microcytic or macrocytic

Answer 4

mean cell volume
low = microcytic (small erythrocytes, less of them)
high = macrocytic (big erythrocytes, less of them)

Question 5

where in the erythrocyte is Hb synthesised

Answer 5

cytoplasm

Question 6

microcytic erythrocytes have high/low volumes of Hb

Answer 6

low

Question 7

what kind of anaemia is caused by lack of raw materials

Answer 7

microcytic

less Hb made, cells are smaller

Question 8

what are features of Hb deficient microcytic erythrocytes

Answer 8

hypochromic - lacking in red colour
pencil cells
target cells

Question 9

what might cause iron deficiency

Answer 9

heavy periods (blood loss)
lack of dietary iron (uncommon in this country)
anaemia of chronic disease - iron levels normal, not bioavailable
GI blood loss
malabsorption of iron (e.g. coeliac)

Question 10

what might cause porphyrin deficiency

Answer 10

lead poisoning

pyridoxine responsive anaemia

Question 11

what might cause globin deficiency

Answer 11

thalassaemia

Question 12

if a patient has lost 1L blood, how much iron have they lost

Answer 12

500ml

iron loss = 1/2 blood loss

Question 13

where is iron stored

Answer 13

macrophages (from RBC breakdown)
liver
haemoglobin

Question 14

where does most iron exist

Answer 14

Hb

Question 15

what is circulating iron bound to

Answer 15

transferrin

Question 16

when is %saturated transferrin decreased

Answer 16

iron deficiency

anaemia of chronic disease

Question 17

when is %saturated transferrin increased

Answer 17

haemachromatosis

Question 18

how is iron stored in liver

Answer 18

as ferritin

Question 19

how do you measure storage iron

Answer 19

serum ferritin

Question 20

how is iron deficiency confirmed

Answer 20

combination of low Hb (functional iron) and low serum ferritin (low storage iron)

Question 21

where is dietary iron absorbed from

Answer 21

proximal small bowel

Question 22

what are the 2 true causes of macrocytic anaemia

Answer 22

megaloblastic

non-megaloblastic

Question 23

what is a megaloblast

Answer 23

abnormally large nucleated red cell precursor with an immature nucleus

Question 24

what is defective in megaloblastic macrocytic anaemias

Answer 24

DNA synthesis and nuclear maturation

preserved Hb and RNA synthesis

Question 25

why are megaloblasts bigger than normal cells

Answer 25

divides fewer times however Hb still accumulates in cytoplasm eventually triggering enucleation left with larger RBCs but less of them

Question 26

what are causes of megaloblastic macrocytic anaemias

Answer 26

B12 and folate deficiencies Drugs inherited abnormalities of enzymes

Question 27

why does B12 and folate deficiency cause megaloblastic anaemia

Answer 27

they provide enough nucleosides for DNA synthesis which allows DNA replication to occur

Question 28

what biochemical pathway does folate catalyse

Answer 28

uridine to thymidine

Question 29

what is the only source of B12

Answer 29

meat and animal food - cobalamine

Question 30

where is B12 released from food

Answer 30

stomach - acidic environment

Question 31

what binds to B12 and where

Answer 31

intrinsic factor | form a complex in proximal small bowel

Question 32

what secretes intrinsic factor

Answer 32

parietal cells in fundus and body of stomach

Question 33

where is the B12-intrinsic factor complex absorbed

Answer 33

terminal ilium

Question 34

what are causes of B12 deficiency

Answer 34

vegans stomach problems - atrophic gastritis, pernicious anaemia small bowel - coeliac, bacterial overgrowth, crohn's

Question 35

what is pernicious anaemia

Answer 35

autoimmune condition resulting in destruction of gastric parietal cells

Question 36

consequences of ineffective gastric parietal cells

Answer 36

no intrinsic factor secreted | therefore B12 cannot be absorbed

Question 37

what are conditions associated with pernicious anaemia

Answer 37

other autoimmune conditions: hypothyroid vitiligo Addison's

Question 38

how is folate absorbed

Answer 38

dietary folates converted to monoglutamate | absorbed in jejunum

Question 39

what are sources of folate

Answer 39

leaf veg and yeast

Question 40

causes of folate deficiency

Answer 40

inadequate dietary intake malabsorption - coeliac, crohn's excess utilisation - pregnancy, malignancy, exfoliating dermatitis, haemolysis drugs - anticonvulsants

Question 41

folate/B12 is more likely due to inadequate dietary intake. Why?

Answer 41

Folate - stores are only last for 4 months | B12 stores last 2-4 years

Question 42

what are clinical features of both B12/folate deficiency

Answer 42

``` anaemia weight loss diarrhoea infertility sore tongue jaundice developmental problems in children ```

Question 43

neurological problems can occur in B12/folate deficiency

Answer 43

B12

Question 44

why do neurological problems occur in B12 deficiency

Answer 44

B12 involved in the formation of myelin

Question 45

neurological manifestations of B12 deficiency

Answer 45

dorsal column abnormalities neuropathy dementia psychiatric manifestations

Question 46

what might the blood film show in macrocytic anaemia

Answer 46

macrovalocytes and hypersegmented neutrophils (3-5 nuclear segments)

Question 47

what anti-bodies indicate pernicious anaemia

Answer 47

anti gastric-parietal cell (antiGPC) | anti intrinsic factor (antIF)

Question 48

what antibody is more specific to pernicious anaemia

Answer 48

antiIF

Question 49

what medication is given to treat B12 deficiency

Answer 49

hydroxycobalamin IM | loading dose for 2 weeks then three monthly life-long

Question 50

what medication is given to treat folate deficiency

Answer 50

folic acid 5mg/day oral

Question 51

when would you do a blood transfusion due to macrocytic anaemia

Answer 51

if life threatening

Question 52

what are causes of non-megaloblastic macrocytic anaemia

Answer 52

alcohol liver disease hypothyroid bone marrow failure (myelodysplasia, myeloma, aplastic anaemia)

Question 53

why might MCV be measured as high when it is actually normal

Answer 53

increase in reticulocyte numbers as a response to acute blood loss cold-agglutinins - clumps of agglutinated red cells which may register as one giant cell

Question 54

why might patients with pernicious anaemia appear mildly jaundiced

Answer 54

intramedullary haemolysis - causes premature red cell death. Results in release of Hb which is conveted to bilirubin