Microcytic and Macrocytic Anaemias

Question 1

define anaemia

Answer 1

reduced total red cell mass

Question 2

what Hb is considered anaemia in males and females?

Answer 2

Hb <130g/l in males

Hb <120g/l in females

Question 3

which law is used when measuring optical density of red blood cells?

Answer 3

beers law

Question 4

why is measuring haematocrit not reliable straight away in someone who’s just suffered a massive bleed?

Answer 4

there will be no change- need to wait as plasma to blood volume will be more accurate

Question 5

what is haemodilution?

Answer 5

lower red blood cell count due to plasma expansion but not actually lost any red cells i.e. giving somone fluids overnight

Question 6

how can anaemia be classified? (2)

Answer 6

decreased production

increased loss/destruction

Question 7

what will reticulocyte count be in somone with an anaemia due to

1) decreased production
2) increased loss/destruction

Answer 7

1) low reticulocyte count
2) high reticulocyte count

Question 8

what is microcytic anaemia?

Answer 8

presence of small red blod cells

Question 9

what are some causes of microcytic anaemia?

Answer 9

iron deficiency

globin deficiency

problems with prophyrin synthesis (v,v rare)

Question 10

what are siderocites?

Answer 10

iron accumulating wrong in place in blood cell

(seen in problems w porphyrin ring synthesis)

Question 11

a problem with Hb production will produce what kind of coloured cells?

Answer 11

hypochromic

Question 12

how is iron deficiency anaemia confirmed?

Answer 12

anaemia (dec functional iron)

low serum ferritn

Question 13

what are some causes of iron deficiency anaemia?

Answer 13

relative deficiency- women of child bearing age/ children

absolute deficiency- vegetarian diet

blood loss

Malabsoprtion- coeliac

Question 14

if menorrhagia is cause of iron deficiency anaemia what is treatment?

Answer 14

ferrosulphate

Question 15

define macroytic anaemia

Answer 15

red cells have larger than normal volume

Question 16

how is red blood cell size expressed?

Answer 16

Mean Corpuscular Volume (MCV)

Question 17

what will HB, RBC and MCV look like in a macrocytic anaemia?

Answer 17

low Hb

low RBC

high MCV

Question 18

what is the range for red blood cell size?

Answer 18

80-100, >100= macrocytic

Question 19

what are the two kinds of true macrocytic anaemia?

Answer 19

megaloblastic

non-megalobastic

Question 20

define megaloblastic anaemia

Answer 20

abnormally large cells with immature nucleus- megaloblasts

Question 21

where is the defect in megaloblastic anaemia?

Answer 21

defect in DNA synthesis

Question 22

RNA and Hb sythesis is preserved in megaloblastic anaemia. how does this cause production of macroytes (lrger cells)?

Answer 22

when Hb level in cell is optimal nucleus is extruded leaving behind bigger than normal red cell (macrocyte)

(cytoplasm etc develops normally but nucleus refuses to divide so left with one massive cell that was meant to be two)

Question 23

why does anaemia occur in megaloblastic anaemia?

Answer 23

even thogh cells are larger there are less as apoptosis occurs to remove defective cells

Question 24

what are some causes of megaloblastic anaemia?

Answer 24

B12 or Folate deficiency

Question 25

what is seen in non-megaloblastic anaemia?

Answer 25

red cell membrane changes

Question 26

what are some causes of non-megaloblastic anaemia?

Answer 26

alcohol liver disease hypothyroidism marrow failure

Question 27

why is spurious macrocytosis also known as 'false'?

Answer 27

the volume of mature red cell is normal but the MCV is measured as high

Question 28

what are some causes of spurious macrocytosis?

Answer 28

inc in reticulocytes in response to acute blood loss/hameolysis cold-agglutinations, clumps registered as one giant cell

Question 29

why does an increase in reticulocyte numbers give an increase in MCV?

Answer 29

reticuloytes are slightly larger than fully matured red cells

Question 30

what are some sources of B12?

Answer 30

meat/eggs

Question 31

where does B12 absoprtion occur?

Answer 31

distal small bowel

Question 32

how is B12 modified in order to be absorbed?

Answer 32

binds to R protein in stomach intrinsic factor released from parietal cells all travel to duodenum- lower pH R protien cleaved and B12 binds to intrinsic factor

Question 33

what are some causes of B12 deficiency?

Answer 33

vegan diet lack of gastric acid pH doesn't change with pancreatic secretion bacterial overgrowth in small bowel

Question 34

where is intrinsic factor released?

Answer 34

gastric parietal cells

Question 35

how does pernicous anaemia cause B12 deficiency?

Answer 35

autoimmune destruction of gastric parietal cell so no longer able to produce intrinsic factor

Question 36

what should you watch out for in hisotry when dianosing pernicious anaemia?

Answer 36

other autoimmune disorders i.e. hypothyroidism, vitiligo, addisons

Question 37

how is pernicous anaemia treated?

Answer 37

IM B12 for life

Question 38

where is folate absorbed?

Answer 38

jejunum

Question 39

what are some causes of foalte deficiency?

Answer 39

inadequate intake malabsortion i.e. coeliac, crohns excess utilisation- haemolysis, pregnancy, malignancy drugs- anticonvulsant

Question 40

what are some sources of folate?

Answer 40

liver, leafy veg, fortified cereals

Question 41

what is the daily requirement of B12 and Folate?

Answer 41

B12- 1.5ug/day Folate- 200ug/day

Question 42

what are the clinical features of B12/folate deficiency?

Answer 42

symtptoms of anaemia wgt loss, diarrhoea sore tongue, jaundice developmental problems in children

Question 43

hypersegmented nuetrophils and macrovalocytes are seen in which kind of anameia?

Answer 43

macrocytic - maegaloblastic anaemia

Question 44

what auto-antibodies can be checked when investigatign macrocytic anaemia?

Answer 44

anti-intrinsic factor anti-gastric paretal cell

Question 45

why can patients with pernicous anaemia present mildly jaundiced?

Answer 45

intramedullary haemolysis causes Hb to be converted to bilirubin causing change in skin colour

Question 46

neurological problems and psychiatric manifestations are more regularly seen in deficiency of B12 or folate?

Answer 46

B12

Question 47

if proximal bowel is removed what anaemia will occur?

Answer 47

iron deficiency anaemia

Question 48

iron deficiency causes which macrocytic/microcytic anaemia?

Answer 48

microcytic

Question 49

B12 or folate deficiency causes macrocytic/microcytic anaemia?

Answer 49

macrocytic

Question 50

removal of the distal bowel will cause which anaemia?

Answer 50

macrocytic due to deficiency in B12